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WO2025177178A2 - Récupération de substance purifiée à partir d'un mélange brut - Google Patents

Récupération de substance purifiée à partir d'un mélange brut

Info

Publication number
WO2025177178A2
WO2025177178A2 PCT/IB2025/051793 IB2025051793W WO2025177178A2 WO 2025177178 A2 WO2025177178 A2 WO 2025177178A2 IB 2025051793 W IB2025051793 W IB 2025051793W WO 2025177178 A2 WO2025177178 A2 WO 2025177178A2
Authority
WO
WIPO (PCT)
Prior art keywords
stream
distillation unit
purified
equal
overhead
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/IB2025/051793
Other languages
English (en)
Other versions
WO2025177178A3 (fr
Inventor
James D. Hastings
Michael C. QUINN III
Douglas RIESTERER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Invista Textiles UK Ltd
Inv Nylon Chemicals Americas LLC
Original Assignee
Invista Textiles UK Ltd
Inv Nylon Chemicals Americas LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Invista Textiles UK Ltd, Inv Nylon Chemicals Americas LLC filed Critical Invista Textiles UK Ltd
Publication of WO2025177178A2 publication Critical patent/WO2025177178A2/fr
Publication of WO2025177178A3 publication Critical patent/WO2025177178A3/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C253/00—Preparation of carboxylic acid nitriles
    • C07C253/32—Separation; Purification; Stabilisation; Use of additives
    • C07C253/34—Separation; Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/82—Purification; Separation; Stabilisation; Use of additives
    • C07C209/84—Purification
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C249/00—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton
    • C07C249/02—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton of compounds containing imino groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00—Systems containing only non-condensed rings
    • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
    • C07C2601/14—The ring being saturated

Definitions

  • This disclosure relates to a method of recovering a purified material from a crude mixture, such as recovering a purified 2-methylglutaronitrile from a crude mixture obtained from an industrial nitriles manufacturing process.
  • 2-Methylglutaronitrile a six-carbon, aliphatic, branched dinitrile, is a useful chemical intermediate and is also known as MGN.
  • MGN can be obtained as a by-product in the manufacture of industrial dinitrile, specifically, adiponitrile.
  • a by-product MGN- containing stream may contain measurable amounts of 2-ethylsuccinonitrile (ESN), adiponitrile (ADN), glycols, phenols, cresols, catechol, other substituted nitriles, trivalent or pentavalent phosphorus species, and the like.
  • DYTEK® MGN (2-methylglutaronitrile) is an example of a commercial MGN product that is > 99.1 wt.% pure.
  • DYTEK® MGN is a high- boiling specialty intermediate used in the fibers, solvent and polymer industries.
  • HMI Hexamethyleneimine
  • DCH 1,2-Diaminocyclohexane
  • the method includes distilling the crude mixture in a first distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream including ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream including ⁇ 1 wt.% adiponitrile of a total first overhead stream mass.
  • the method includes distilling the first bottom stream in a second distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a second bottom stream including > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture.
  • the method includes obtaining at least one of a second overhead stream and a side-draw stream from the second distillation unit.
  • the method optionally includes distilling at least one of the second overhead stream and the side-draw stream in a third distillation unit having a head pressure in a range of 10 to 80 mmHg to produce a third overhead stream including ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass and a third bottom stream including ⁇ 0.5 wt.% 2-ethylsuccinonitrile of a total third bottom stream mass.
  • the method also includes bringing together the first overhead stream, the second bottom stream, and optionally the third bottom stream, to form a tail mixture including 2- cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass.
  • Various aspects of the present disclosure provide a method of recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture including about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities.
  • the method includes distilling the crude mixture in a first distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream including ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream including ⁇ 1 wt.% adiponitrile of a total first overhead stream mass.
  • the method includes distilling the first bottom stream in a second distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a second bottom stream including > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture.
  • the method includes obtaining at least one of a second overhead stream and a side-draw stream from the second distillation unit.
  • the purified 2-methylglutaronitrile includes > 99.1 wt.% 2- methylglutaronitrile, ⁇ 0.5 wt.% 2-ethylsuccinonitrile, ⁇ 0.2 wt.% adiponitrile, ⁇ 0.2 wt.% of 2-cyanocyclopentylideneimine, and ⁇ 0.2 wt.% water of a mass of the purified 2- methylglutaronitrile.
  • Various aspects of the present disclosure provide a method of recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture including about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities.
  • the method includes distilling at least one of the second overhead stream and the side-draw stream in a third distillation unit having a head pressure in a range of 10 to 80 mmHg to produce a third overhead stream including ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass and a third bottom stream including ⁇ 0.5 wt.% 2-ethylsuccinonitrile of a total third bottom stream mass.
  • the method also includes bringing together the first overhead stream, the second bottom stream, and the third bottom stream, to form a tail mixture including 2- cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass.
  • the third overhead stream is the purified 2-methylglutaronitrile.
  • the purified 2- methylglutaronitrile includes > 99.1 wt.% 2-methylglutaronitrile, ⁇ 0.5 wt.% 2- ethylsuccinonitrile, ⁇ 0.2 wt.% adiponitrile, ⁇ 0.2 wt.% of 2-cyanocyclopentylideneimine, and ⁇ 0.2 wt.% water of a mass of the purified 2-methylglutaronitrile.
  • Various aspects of the present disclosure provide a method of recovering a purified 1,2-diaminocyclohexane (DCH) from a crude mixture, the crude mixture including about 65 to about 80 wt.% DCH, about 10 to about 20 wt.% hexamethylenediamine (HMD), about 0 to 5 wt.% hexamethyleneimine (HMI), about 0 to about 5 wt.% 2-(aminomethyl)- cyclopentylamine (AMC), about 0 to about 5 wt.% 2-methyl-pentamethylenediamine (MPMD), and about 0 to about 2 wt.% other impurities including n-hexylamine, cyclohexylamine, or a combination thereof.
  • HMD hexamethylenediamine
  • HMI hexamethyleneimine
  • AMC 2-(aminomethyl)- cyclopentylamine
  • MPMD 2-methyl-pentamethylenediamine
  • Various aspects of the present disclosure provide an apparatus for recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture including about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities.
  • the apparatus includes a first distillation unit configured to distill the crude mixture at a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream including ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream including ⁇ 1 wt.% adiponitrile of a total first overhead stream mass.
  • the apparatus includes a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 20 to 100 mmHg to produce a second bottom stream including > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a side-draw stream.
  • the apparatus optionally includes a third distillation unit configured to distill at least one of the second overhead stream and the side-draw stream at a head pressure in a range of 10 to 80 mmHg to produce a third overhead stream including ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass and a third bottom stream including ⁇ 0.5 wt.% 2-ethylsuccinonitrile of a total third bottom stream mass.
  • the apparatus includes one or more flow channels configured to bring together the first overhead stream, the second bottom stream, and optionally the third bottom stream, to form a tail mixture including 2-cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass.
  • the optional third distillation unit is not present, and wherein the second overhead stream, the side-draw stream, or a combination thereof, is the purified 2-methylglutaronitrile; or the optional third distillation unit is present, and wherein the third overhead stream is the purified 2-methylglutaronitrile.
  • the purified 2- methylglutaronitrile includes > 99.1 wt.% 2-methylglutaronitrile, ⁇ 0.5 wt.% 2- ethylsuccinonitrile, ⁇ 0.2 wt.% adiponitrile, ⁇ 0.2 wt.% of 2-cyanocyclopentylideneimine, and ⁇ 0.2 wt.% water of a mass of the purified 2-methylglutaronitrile.
  • Various aspects of the present disclosure provide an apparatus for recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture including about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities.
  • the apparatus includes a first distillation unit configured to distill the crude mixture at a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream including ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream including ⁇ 1 wt.% adiponitrile of a total first overhead stream mass.
  • the apparatus includes a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 20 to 100 mmHg to produce a second bottom stream including > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a side-draw stream.
  • the apparatus also includes one or more flow channels configured to bring together the first overhead stream and the second bottom stream, to form a tail mixture including 2-cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass.
  • the second overhead stream, the side-draw stream, or a combination thereof, is the purified 2-methylglutaronitrile.
  • the purified 2- methylglutaronitrile includes > 99.1 wt.% 2-methylglutaronitrile, ⁇ 0.5 wt.% 2- ethylsuccinonitrile, ⁇ 0.2 wt.% adiponitrile, ⁇ 0.2 wt.% of 2-cyanocyclopentylideneimine, and ⁇ 0.2 wt.% water of a mass of the purified 2-methylglutaronitrile.
  • the apparatus includes a first distillation unit configured to distill the crude mixture at a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream including ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream including ⁇ 1 wt.% adiponitrile of a total first overhead stream mass.
  • the apparatus includes a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 20 to 100 mmHg to produce a second bottom stream including > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a side-draw stream.
  • the apparatus includes a third distillation unit configured to distill at least one of the second overhead stream and the sidedraw stream at a head pressure in a range of 10 to 80 mmHg to produce a third overhead stream including ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass and a third bottom stream including ⁇ 0.5 wt.% 2-ethylsuccinonitrile of a total third bottom stream mass.
  • the apparatus also includes one or more flow channels configured to bring together the first overhead stream, the second bottom stream, and the third bottom stream, to form a tail mixture including 2-cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass.
  • the apparatus includes a first distillation unit configured to distill the crude mixture at a head pressure in a range of 400 to 500 mmHg to produce a first bottom stream including concentrated HMI including HMD, and a first overhead stream including n-hexylamine and optionally including water.
  • the apparatus also includes a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 100 to 200 mmHg to produce a second bottom stream including concentrated HMD including HMI, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a sidedraw stream.
  • the second overhead stream, the side-draw stream, or a combination thereof, is the purified HMI.
  • the purified HMI is at least 99 wt.% HMI.
  • Various aspects of the present disclosure provide an apparatus for recovering a purified 1,2-diaminocyclohexane (DCH) from a crude mixture, the crude mixture including about 65 to about 80 wt.% DCH, about 10 to about 20 wt.% hexamethylenediamine (HMD), about 0 to 5 wt.% hexamethyleneimine (HMI), about 0 to about 5 wt.% 2-(aminomethyl)- cyclopentylamine (AMC), about 0 to about 5 wt.% 2-methyl-pentamethylenediamine (MPMD), and about 0 to about 2 wt.% other impurities including n-hexylamine, cyclohexylamine, or a combination thereof.
  • HMD hexamethylenediamine
  • HMI hexamethyleneimine
  • AMC 2-(aminomethyl)- cyclopentylamine
  • MPMD 2-methyl-pentamethylenediamine
  • the apparatus includes a first distillation unit configured to distill the crude mixture at a head pressure in a range of 700 to 850 mmHg to produce a first bottom stream including concentrated DCH optionally including HMD, AMC, MPMD, or a combination thereof, and a first overhead stream including HMD and optionally including AMC, MPMD, or a combination thereof.
  • the apparatus also includes a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 100 to 200 mmHg to produce a second bottom stream including concentrated HMD including DCH and optionally including AMC, MPMD, or a combination thereof, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a sidedraw stream.
  • the second overhead stream, the side-draw stream, or a combination thereof, is the purified DCH.
  • the purified DCH is at least 98.5 wt.% DCH.
  • Various aspects of the method and apparatus of the present disclosure provide certain advantages over other methods for recovering a purified material, such as purified 2- methylglutaronitrile, hexamethyleneimine, or diaminocyclohexane, from a crude mixture.
  • a purified material such as purified 2- methylglutaronitrile, hexamethyleneimine, or diaminocyclohexane
  • the method and apparatus of the present disclosure can provide a purified material having a higher degree of purity (i.e., a higher weight percentage of 2-methylglutaronitrile, a higher weight percentage of hexamethyleneimine, or a higher weight percentage of diaminocyclohexane) as compared to other methods for recovering the purified material.
  • the method and apparatus of the present disclosure can provide a purified material having a lower concentration of one or more impurities that can cause problems in subsequent processing steps as compared to other methods for recovering the purified material.
  • the method and apparatus of the present disclosure can provide a purified 2-methylglutaronitrile having a lower concentration of particular impurities that can cause problems in subsequent processing steps as compared to other methods for recovering 2-methylglutaronitrile, such as a lower concentration of 2- ethylsuccinonitrile (ESN) and/or 2-cyanocyclopentylideneimine (CPI).
  • ESN 2- ethylsuccinonitrile
  • CPI 2-cyanocyclopentylideneimine
  • the method and apparatus of the present disclosure experiences less downtime due to clogging, as compared to other methods for recovering purified materials from crude mixtures, such as compared to other methods for recovering 2-methylglutaronitrile, hexamethyleneimine, or diaminocyclohexane.
  • FIG. 1 is a schematic representation of an aspect 100 according to the present disclosure.
  • FIG. 2 is a schematic representation of an aspect 200 according to the present disclosure.
  • FIG. 3 is a schematic representation of an aspect 300 according to the present disclosure.
  • FIG. 4 is a schematic representation of an aspect 400 according to the present disclosure.
  • FIG. 6 is a schematic representation of an aspect 600 according to the present disclosure.
  • the acts can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.
  • substantially refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.
  • substantially free of can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that the composition is about 0 wt.% to about 5 wt.% of the material, or about 0 wt.% to about 1 wt.%, or about 5 wt.% or less, or less than, equal to, or greater than about 4.5 wt.%, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt.% or less.
  • substantially free of can mean having a trivial amount of, such that a composition is about 0 wt.% to about 5 wt.% of the material, or about 0 wt.% to about 1 wt.%, or about 5 wt.% or less, or less than, equal to, or greater than about 4.5 wt.%, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt.% or less, or about 0 wt.%.
  • All publications, including non-patent literature e.g., scientific journal articles), patent application publications, and patents mentioned in this specification are incorporated by reference as if each were specifically and individually indicated to be incorporated by reference.
  • HMD hexamethylenediamine
  • ADN adiponitrile
  • Adiponitrile is synthesized from a double hydrocyanation reaction between butadiene and a cyanide source. This process chemistry also generates other co-products, for example, six-carbon branched dinitriles such as 2-methylglutaronitrile (MGN) and 2-ethyl-succinonitrile (ESN).
  • MGN 2-methylglutaronitrile
  • ESN 2-ethyl-succinonitrile
  • Hydrogenation of high purity MGN is an important chemical process for making its corresponding diamine, namely, 2-methylpentamethylene diamine or MPMD, which has uses including as a monomer for the manufacture of various polyamides. Since the impurities present in the crude MGN feed tend to deactivate the hydrogenation catalyst, it is desirable to remove them from the MGN feed. Further, some of these impurities tend to interfere with certain downstream chemistries during the hydrogenation to form MPMD, thereby negatively impacting the desired product yield and/or separation. Of primary importance in this regard is 2-ethylsuccinonitrile (ESN), which has a boiling point close to that of 2-methylglutaronitrile. Another process impurity is 2-cyanocyclopentylideneimine (CPI).
  • ESN 2-ethylsuccinonitrile
  • CPI 2-cyanocyclopentylideneimine
  • Various aspects of the present disclosure provide a method of recovering a purified 2-methylglutaronitrile from a crude mixture.
  • the crude mixture can include about 70 to about 90 wt.% 2-methylglutaronitrile (e.g., less than or equal to 90 wt.%, greater than or equal to 70 wt.%, and less than, equal to, or greater than 71 wt.%, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, or 89 wt.%), about 1 to about 20 wt.% 2- ethylsuccinonitrile (e.g., less than or equal to 20 wt.%, greater than or equal to 1 wt.% and less than, equal to, or greater than 2 wt.%, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 wt.%), about 1 to
  • the crude mixture can further include ⁇ 5 wt.% phenols and cresols (e.g., less than or equal to 5 wt.%, 4, 3, 2, 1, 0.5, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 10 wt.% water (e.g., less than or equal to 9 wt.%, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 2 wt.% pentenenitrile (e.g., less than or equal to 2 wt.%, 1.5, 1, 0.5, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 0.2 wt.% boronate esters or glycols (e.g., less than or equal to 0.2 wt.%, 0.15, 0.1, 0.05, or 0.01 wt.%, or about
  • hydrogen cyanide e.g., less than or equal to 100 ppm, 80, 60, 40, 20, 10, or 5 ppm, or about 0 ppm
  • ⁇ 100 ppm by wt. benzene e.g., less than or equal to 100 ppm, 80, 60, 40, 20, 10, or 5 ppm, or about 0 ppm
  • weight percentages are in terms of the total crude mixture mass.
  • the method can include distilling the crude mixture in a first distillation unit to produce a first bottom stream and a first overhead stream.
  • the first bottom stream can include ⁇ 1 wt.% 2-ethylsuccinonitrile of the total first bottom stream mass (e.g., less or equal to 0.8, 0.6, 0.4, 0.2, or 0.1 wt.%, or about 0 wt.%).
  • the first overhead stream can include ⁇ 1 wt.% adiponitrile of a total first overhead stream mass (e.g., less than or equal to 0.8, 0.6, 0.4, 0.2, or 0.1 wt.%, or about 0 wt.%).
  • the first distillation unit can have a head pressure in a range of 20 to 100 mmHg, or 40 to 60 mmHg, or less than or equal to 100 mmHg, greater than or equal to 20 mmHg, and less than, equal to, or greater than 30 mmHg, 35, 40, 45, 50, 55, 60, 65, 70, 80, or 99 mmHg.
  • the distilling the crude mixture in the first distillation unit can include introducing the crude mixture into an upper half of the first distillation unit.
  • the first distillation unit can include two or more packed sections that together provide an equivalent of at least 30-80 total theoretical distillation stages, such as at least 30, 40, 45, 50, 55, 60, 65, or 70.
  • the method can include passing process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • the overhead and bottom temperatures in the first distillation unit can be maintained in ranges of 45-60 °C (e.g., less than or equal to 60 °C, greater than or equal to 45 °C, and less than, equal to, or greater than 46 °C, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59 °C) and 190-205 °C (e.g., less than or equal to 205 °C, greater than or equal to 190 °C, and less than, equal to, or greater than 191 °C, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, or 204 °C), respectively.
  • 45-60 °C e.g., less than or equal to 60 °C, greater than or equal to 45 °C, and less than, equal to, or greater than 46 °C, 47, 48, 49, 50, 51, 52, 53, 54
  • the method can include distilling the first bottom stream in a second distillation unit to produce a second bottom stream and to produce at least one of a second overhead stream and a side-draw stream from the second distillation unit.
  • the second bottom stream can include > 80% of the 2-cyanocyclopentylideneimine content present in the crude mixture (e.g., greater than or equal to 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 wt.%, or about 100 wt.%).
  • the second distillation unit can have a head pressure in a range of 20 to 100 mmHg, or 40 to 60 mmHg, or less than or equal to 100 mmHg, greater than or equal to 20 mmHg, and less than, equal to, or greater than 30 mmHg, 35, 40, 45, 50, 55, 60, 65, 70, 80, or 90 mmHg.
  • the second overhead stream and/or sidedraw stream can include > 99.1 wt.% 2-methylglutaronitrile (e.g., greater than or equal to about 99.1 wt.%, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, or 99.9 wt.%, or about 100 wt.%), ⁇ 0.5 wt.% 2-ethylsuccinonitrile (e.g., less than or equal to 0.5 wt.%, 0.4, 0.3, 0.2, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 0.2 wt.% adiponitrile (e.g., less than or equal to 0.2 wt.%, 0.15, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 0.2 wt.% of 2-cyanocyclopentylideneimine (e.g., less
  • the method can include obtaining the side-draw stream from near a top section of the second distillation unit.
  • the distilling of the first bottom stream in the second distillation unit can include introducing the first bottom stream into a lower half of the second distillation unit.
  • the second distillation unit can include two or more packed sections that together provide an equivalent of at least 10-50 total theoretical distillation stages, such as at least 10, 15, 20, 25, 30, 35, 40, or 45.
  • the method can include passing process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • the overhead and bottom temperature in the second distillation unit can be maintained in ranges of 45-60 °C (e.g., less than or equal to 60 °C, greater than or equal to 45 °C, and less than, equal to, or greater than 46 °C, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, or 59 °C) and 190-205 °C, respectively (e.g., less than or equal to 205 °C, greater than or equal to 190 °C, or less than, equal to, or greater than 191 °C, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, or 204 °C).
  • 45-60 °C e.g., less than or equal to 60 °C, greater than or equal to 45 °C, and less than, equal to, or greater than 46 °C, 47, 48, 49, 50, 51, 52, 53, 54
  • the method can optionally include distilling at least one of the second overhead stream and the side-draw stream in a third distillation unit to produce a third overhead stream and a third bottom stream.
  • the optional distillation in the third column is not performed.
  • the optional distillation in the third column is performed, and the third overhead stream can be the purified 2-methylglutaronitrile.
  • the third overhead stream can include ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass (e.g., less than or equal to 0.1 wt.%, 0.08, 0.06, 0.04, 0.02, or 0.01 wt.%, or about 0 wt.%).
  • the third bottom stream can include ⁇ 0.5 wt.% 2- ethylsuccinonitrile of a total third bottom stream mass (e.g., less than or equal to 0.5 wt.%, 0.4, 0.3, 0.2, or 0.1 wt.%, or about 0 wt.%).
  • the third distillation unit can have a head pressure in a range of 10 to 80 mmHg, or 30 to 50 mmHg, or less than 80 mmHg, greater than 10 mmHg, and less than, equal to, or greater than 20 mmHg, 30, 35, 40, 45, 50, 55, 60, 65, 70, 80, or 90 mmHg.
  • the overhead and bottom temperatures in the third distillation unit can be maintained in ranges of 55-80 °C (e.g., less than or equal to 80 °C, greater than or equal to 55 °C, and less than, equal to, or greater than 56 °C, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, or 78 °C) and 160-190 °C (e.g., less than or equal to 190 °C, greater than or equal to 160 °C, and less than, equal to, or greater than 162 °C, 164, 166, 168, 170, 172, 174, 176, or 178 °C), respectively.
  • 55-80 °C e.g., less than or equal to 80 °C, greater than or equal to 55 °C, and less than, equal to, or greater than 56 °C, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, or
  • the distilling at least one of the second overhead stream and the sidedraw stream can include introducing at least one of the second overhead stream and the sidedraw stream to a lower half of the third distillation unit.
  • the third distillation unit can include two or more packed sections that together provide an equivalent of at least 10-50 total theoretical distillation stages, such as at least 10, 15, 20, 25, 30, 35, 40, or 45.
  • the method can include passing process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the third overhead stream and to provide a third noncondensed vapor purge material.
  • the second overhead stream, the side-draw stream, or a combination thereof can be the purified 2- methylglutaronitrile.
  • the second overhead stream can be the purified 2-methylglutaronitrile.
  • the side-draw stream can be the purified 2-methylglutaronitrile.
  • a combination of the second overhead stream and the side-draw stream can be the purified 2-methylglutaronitrile.
  • the third overhead stream can be the purified 2-methylglutaronitrile.
  • the purified 2-methylglutaronitrile (e.g., the sidedraw stream, the second overhead stream, a combination of the side-draw stream and the second overhead stream, or the third overhead stream) can be > 99.1 wt.% 2- methylglutaronitrile (e.g., greater than or equal to 99.1 wt.%, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, 99.95, or 99.99 wt.%, or about 100 wt.%), ⁇ 0.5 wt.% 2-ethylsuccinonitrile (e.g., less than or equal to 0.5 wt.%, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 0.2 wt.% adiponitrile (e.g., less than or equal to 0.2, 0.18, 0.15, 0.
  • the method can include bringing together the first overhead stream, the second bottom stream, and in aspects wherein the optional third distillation unit is present the third bottom stream, to form a tail mixture.
  • the tail mixture can include 2- cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass (e.g., less than or equal to 30 wt.%, greater than or equal to 1 wt.%, and less than, equal to, or greater than 2 wt.%, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28 wt.%).
  • the method can include cooling the tail mixture to a temperature of 40-60 °C in a heat exchange device (e.g., less than or equal to 60 °C, greater than or equal to 40 °C, and less than, equal to, or greater than 42 °C, 44, 46, 48, 50, 52, 54, 56, or 58 °C).
  • the method can further include heat-tracing the tail mixture by suitable conventional means.
  • the method can further include adding water to the tail mixture.
  • the method can be performed continuously with less than 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or less than 1 flow interruptions from the tail mixture (e.g., clogs) per year of operation.
  • the method can further include collecting a portion of the first bottom stream as a product stream.
  • the method can further include collection a portion of the first bottom stream, a portion of the second overhead stream, a portion of the side-draw stream, or a combination thereof, as a product stream.
  • the product stream can be 93-95 wt.% 2-methylglutaronitrile (e.g., less than or equal to 95 wt.%, greater than or equal to 93 wt.%, and less than, equal to, or greater than 93.2 wt.%, 93.4, 93.6, 93.8, 94, 94.2, 94.4, 94.6, or 94.8 wt.%), 4-6 wt.% adiponitrile (e.g., less than or equal to 6 wt.%, greater than or equal to 4 wt.%, and less than, equal to, or greater than 4.2 wt.%, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, or 5.8 wt.%), less than 1 wt.% 2- ethylsuccinonitrile (e.g., less than or equal to 0.9 wt.%, 0.8, 0.6, 0.4, 0.2, 0.1, 0.01 wt.% or about 0
  • the product stream can be hydrogenated in the presence of hydrogen and ammonia to hydrogenate the 2-methylglutaronitrile and to produce the branched diamine methyl-pentamethylenediamine (MPMD).
  • the hydrogenation can convert the adiponitrile and any 2-ethylsuccinonitrile to their respective diamines, hexamethylenediamine (HMD) and 1,3 -pentanediamine (13PDA).
  • the hydrogenation can convert the 2-cyanocyclopentylideneimine to its corresponding amine, 2-(aminomethyl)- cyclopentylamine (AMC).
  • Various aspects of the present disclosure provide a method of recovering a purified hexamethyleneimine (HMI) from a crude mixture using the same or similar first and second distillation units as described for use herein for recovering a purified 2- methylglutaronitrile from a crude mixture.
  • the first distillation unit for the method of recovering a purified HMI can be the same or similar in design, internals, configuration aspects, or a combination thereof, to the first distillation unit for the method of recovering a purified 2-methylglutaronitrile.
  • the second distillation unit for the method of recovering a purified HMI can be the same or similar in design, internals, configuration aspects, or a combination thereof, to the second distillation unit for the method of recovering a purified 2- methylglutaronitrile.
  • the apparatus can include a first distillation unit configured to distill the crude mixture to produce a first bottom stream and a first overhead stream.
  • the first distillation unit can be configured to operate at a head pressure in a range of 20 to 100 mmHg, 40 to 60 mmHg, or less than or equal to 100 mmHg, greater than or equal to 20 mmHg, and less than, equal to, or greater than 30 mmHg, 35, 40, 45, 50, 55, 60, 65, 70, 80, or 99 mmHg.
  • the second bottom stream can include > 80% of the 2- cyanocyclopentylideneimine content present in the crude mixture (e.g., greater than or equal to 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 wt.%, or about 100 wt%).
  • the second distillation unit can be configured to provide the side-draw stream from near a top section of the second distillation unit.
  • the second distillation unit can be configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • the second distillation unit can include two or more packed sections that together provide an equivalent of at least 10-50 total theoretical distillation stages, such as at least 10, 15, 20, 25, 30, 35, 40, or 45.
  • the second distillation unit can be configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • the third overhead stream can include ⁇ 0.1 wt.% of 2-cyanocyclopentylideneimine of the total third overhead stream mass (e.g., less than or equal to 0.1 wt.%, 0.08, 0.06, 0.04, 0.02, or 0.01 wt.%, or about 0 wt.%).
  • the third bottom stream can include ⁇ 0.5 wt.% 2- ethylsuccinonitrile of a total third bottom stream mass (e.g., less than or equal to 0.5 wt.%, 0.4, 0.3, 0.2, or 0.1 wt.%, or about 0 wt.%).
  • the third distillation unit can be configured to maintain overhead and bottom temperatures therein in ranges of 55-80 °C e.g., less than or equal to 80 °C, greater than or equal to 55 °C, and less than, equal to, or greater than 56 °C, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, or 78 °C) and 160-190 °C (e.g., less than or equal to 190 °C, greater than or equal to 160 °C, and less than, equal to, or greater than 162 °C, 164, 166, 168, 170, 172, 174, 176, or 178 °C), respectively.
  • 55-80 °C e.g., less than or equal to 80 °C, greater than or equal to 55 °C, and less than, equal to, or greater than 56 °C, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76
  • the third distillation unit can be configured for the at least one of the second overhead stream and the side-draw stream to be introduced to a lower half of the third distillation unit.
  • the third distillation unit can include two or more packed sections that together provide an equivalent of at least 10-50 total theoretical distillation stages, such as at least 10, 15, 20, 25, 30, 35, 40, or 45.
  • the third distillation unit can be configured to pass process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and to condense the process vapors to provide a liquid which is the third overhead stream and to provide a third non-condensed vapor purge material.
  • the apparatus can also include one or more flow channels configured to bring together the first overhead stream, the second bottom stream, and optionally the third bottom stream, to form a tail mixture including 2-cyanocyclopentylideneimine in the range of 1 to 30 wt.% of a total tail mixture mass (e.g., less than or equal to 30 wt.%, greater than or equal to 1 wt.%, and less than, equal to, or greater than 2 wt.%, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28 wt.%).
  • a total tail mixture mass e.g., less than or equal to 30 wt.%, greater than or equal to 1 wt.%, and less than, equal to, or greater than 2 wt.%, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, or 28 wt.%.
  • the apparatus can further include a heat exchange device configured to cool the tail mixture to a temperature of 40-60 °C (e.g., less than or equal to 60 °C, greater than or equal to 40 °C, and less than, equal to, or greater than 42 °C, 44, 46, 48, 50, 52, 54, 56, or 58 °C).
  • the apparatus can further include a provision to heat-trace the tail mixture by suitable conventional means.
  • the apparatus can further include a provision to add water to the tail mixture.
  • the purified 2- methylglutaronitrile (e.g., the side-draw stream, the second overhead stream, a combination of the side-draw stream and the second overhead stream, or the third overhead stream) can be > 99.1 wt.% 2-methylglutaronitrile (e.g., greater than or equal to 99.1 wt.%, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, 99.95, or 99.99 wt.%, or about 100 wt.%), ⁇ 0.5 wt.% 2- ethylsuccinonitrile (e.g., less than or equal to 0.5 wt.%, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, or 0.01 wt.%, or about 0 wt.%), ⁇ 0.2 wt.% adiponitrile (e.g., less than or equal to 0.2, 0.18, 0.15
  • the apparatus can be operatable continuously with less than 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 flow interruptions (e.g., clogs) from the tail mixture per year of operation.
  • the apparatus can be configured for collection of a portion of the first bottom stream as a product stream.
  • the apparatus can be configured for collection a portion of the first bottom stream, a portion of the second overhead stream, a portion of the side-draw stream, or a combination thereof, as a product stream.
  • the product stream can be 93-95 wt.% 2- methylglutaronitrile (e.g., less than or equal to 95 wt.%, greater than or equal to 93 wt.%, and less than, equal to, or greater than 93.2 wt.%, 93.4, 93.6, 93.8, 94, 94.2, 94.4, 94.6, or 94.8 wt.%), 4-6 wt.% adiponitrile (e.g., less than or equal to 6 wt.%, greater than or equal to 4 wt.%, and less than, equal to, or greater than 4.2 wt.%, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, or 5.8 wt.%), less than 1 wt.% 2-ethylsuccinonitrile (e.g., less than or equal to 0.9 wt.%, 0.8, 0.6, 0.4, 0.2, 0.1, 0.01 wt.% or about 0
  • the product stream can be hydrogenated in the presence of hydrogen and ammonia to hydrogenate the 2- methylglutaronitrile and to produce the branched diamine methyl-pentamethylenediamine (MPMD).
  • the hydrogenation can convert the adiponitrile and any 2-ethylsuccinonitrile to their respective diamines, hexamethylenediamine (HMD) and 1,3-pentanediamine (13PDA).
  • the hydrogenation can convert the 2-cyanocyclopentylideneimine to its corresponding amine, 2-(aminomethyl)-cyclopentylamine (AMC).
  • the resulting hydrogenated product stream can be mainly MPMD (e.g., 90 wt.% or more MPMD, such as less than or equal to 100 wt.%, greater than or equal to 90 wt.%, and less than, equal to, or greater than 91 wt.%, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, or 99.99 wt.%) with other components (e.g., HMD, 13PDA, AMC, or a combination thereof) as less than 10 wt.% of the hydrogenated product stream (e.g., less than or equal to 9 wt.%, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1, 0.05, or 0.01 wt.%).
  • MPMD e.g., 90 wt.% or more MPMD, such as less than or equal to 100 wt.%, greater than or equal to 90 wt.%, and less than, equal to, or greater than 91 wt
  • the hydrogenated product stream can optionally be refined by stripping most of the HMD and 13PDA by distillation or other separation means such as extraction, membrane separation, and the like.
  • the hydrogenated product stream, or the refined hydrogenated product stream can be a semi-refined MPMD product stream, suitable for some industrial applications that are less sensitive to AMC impurity in MPMD, such as epoxy curing, reactive coatings, and other applications wherein the residual AMC does not cause a problem.
  • Various aspects of the present disclosure provide an apparatus for recovering a purified hexamethyleneimine (HMI) from a crude mixture using the same or similar first and second distillation units as described for use herein for recovering a purified 2- methylglutaronitrile from a crude mixture.
  • the first distillation unit for the apparatus for recovering a purified HMI can be the same or similar in design, internals, configuration, or a combination thereof, to the first distillation unit for the apparatus for recovering a purified 2- methylglutaronitrile.
  • the second distillation unit for the apparatus for recovering a purified HMI can be the same or similar in design, internals, configuration, or a combination thereof, to the second distillation unit for the apparatus for recovering a purified 2- methylglutaronitrile.
  • the crude mixture for use in the apparatus for recovering the purified HMI can include about 80 to about 90 wt.% HMI (e.g., less than or equal to 90 wt.%, greater than or equal to 80 wt.%, or less than, equal to, or greater than 81 wt.%, 82, 83, 84, 85, 86, 87, 88, or 89 wt.%), about 5 to about 15 wt.% n-hexylamine (e.g., less than or equal to 15 wt.%, greater than or equal to 5 wt.%, or less than, equal to, or greater than 6 wt.%, 7, 8, 9, 10, 11, 12, 13, or 14 wt.%), about 0 to 5 wt.% water (e.g., less than or equal to 5 wt.%, greater than or equal to 0 wt.%, and less than, equal to, or greater than 4 wt.%, 3, 2, 1.5, 1,
  • the apparatus for recovering the purified HMI can include a first distillation unit configured to distill the crude mixture to produce a first bottom stream including concentrated HMI including HMD, and a first overhead stream including n-hexylamine and optionally including water.
  • the first distillation unit can have a head pressure maintained in a range of 400 to 500 mmHg, or about 425 to 450 mmHg, or less than or equal to 500 mmHg, greater than or equal to 400 mmHg, and less than, equal to, or greater than 405 mmHg, 410, 415, 420, 425, 430, 435, 440, 445, 450, 455, 460, 465, 470, 475, 480, 485, 490, or 495 mmHg.
  • the first distillation unit can have a base pressure maintained in a range of about 400 to 500 mmHg, or about 450 to 475 mmHg, or less than or equal to 500 mmHg, greater than or equal to 400 mmHg, and less than, equal to, or greater than 405 mmHg, 410, 415, 420, 425, 430, 435, 440, 445, 450, 455, 460, 465, 470, 475, 480, 485, 490, or 495 mmHg.
  • the head conditions of the first distillation unit can be maintained at about 100 °C to 115 °C, or less than or equal to 115 °C, greater than or equal to 100 °C, and less than, equal to, or greater than 101 °C, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, or 114 °C.
  • the base conditions of the first distillation unit can be maintained at about 110 °C to 130 °C, or less than or equal to 130 °C, greater than or equal to 110 °C, and less than, equal to, or greater than 112 °C, 114, 116, 118, 120, 122, 124, 126, or 128 °C.
  • the first distillation unit can be configured for the crude mixture to be introduced into an upper half of the first distillation unit.
  • the first distillation unit can include two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages, such as 50 to 80 stages, or less or equal to 80, greater than or equal to 50, and less than, equal to, or greater than 55, 60, 65, 70, or 75 theoretical distillation stages.
  • the first distillation unit can be configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • the apparatus for recovering the purified HMI can include a second distillation unit configured to distill the first bottom stream to produce a second bottom stream including concentrated HMD including HMI, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a side-draw stream.
  • the second distillation unit can have a head pressure maintained in a range of about 100 to 200 mmHg, or about 145 to 155 mmHg, or less than or equal to 200 mmHg, greater than or equal to 100 mmHg, and less than, equal to, or greater than 105 mmHg, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, or 195 mmHg.
  • the second distillation unit can have a base pressure maintained in the range of about 100 to 200 mmHg, or about 155 to 165 mmHg, or less than or equal to 200 mmHg, greater than or equal to 100 mmHg, and less than, equal to, or greater than 105 mmHg, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, or 195 mmHg.
  • the head conditions of the second distillation unit can be maintained at about 80 °C to 90 °C, or less than or equal to 90 °C, greater than or equal to 80 °C, and less than, equal to, or greater than 81 °C, 82, 83, 84, 85, 86, 87, 88, or 89 °C.
  • the base conditions of the second distillation unit can be maintained at about 130 °C to 140 °C, or less than or equal to 140 °C, greater than or equal to 130 °C, and less than, equal to, or greater than 131 °C, 132, 133, 134, 135, 136, 137, 138, or 139 °C.
  • the second distillation unit can be configured for the first bottom stream to be introduced into an upper half of the second distillation unit.
  • the second distillation unit can include two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages, or 30 to 60 stages, or less than or equal to 60, greater than or equal to 30, and less than, equal to, or greater than 35, 40, 45, 50, or 55 theoretical distillation stages.
  • the second distillation unit can be configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • the second overhead stream, the side-draw stream, or a combination thereof, can be the purified HMI.
  • the side-draw stream can be removed from near a top section of the second distillation unit.
  • the second overhead stream can be the purified HMI.
  • the sidedraw stream can be the purified HMI.
  • a combination of the second overhead stream and the side-draw stream can be the purified HMI.
  • the purified HMI can be at least 99 wt.% HMI, such as 99 wt.% to 99.9 wt.% HMI, or 99 wt.% to 100 wt.% HMI, or less than or equal to 100 wt.%, greater than or equal to 99 wt.%, and less than, equal to, or greater than 99.1 wt.%, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, or 99 wt.%.
  • the purified HMI can be less than or equal to 0.40 wt.% cyclohexylamine (e.g., less than or equal to 0.4 wt.%, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, 0.01 wt.%, or about 0 wt.%), less than or equal to 0.02 wt.% n-hexylamine (e.g., less than or equal to about 0.02 wt.%, 0.01, 0.005, 0.001 wt.%, or about 0 wt.%), less than or equal to 0.07 wt.% water (e.g., less than or equal to about 0.07 wt.%, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, 0.005, 0.001 wt.%, or about 0 wt.%), and less than or equal to 0.02 wt.% HMD (e.g., less than or equal to about 0.02 w
  • the purified HMI can have the same composition as the HMI product commercially available from INVISTA under the tradename Dytek® HMI amine.
  • the purified HMI can find applications in pharmaceuticals, textile chemicals, dyes, agricultural chemicals, corrosion inhibition, inks, zeolite manufacture, ore flotation, or rubber chemicals. Apparatus for recovering 1,2-diaminocyclohexane.
  • Various aspects of the present disclosure provide an apparatus for recovering a purified 1,2-diaminocyclohexane (DCH) from a crude mixture using the same or similar first and second distillation units as described for use herein in the apparatus for recovering a purified 2-methylglutaronitrile from a crude mixture.
  • the first distillation unit for the apparatus for recovering a purified DCH can be the same or similar in design, internals, configuration aspects, or a combination thereof, to the second distillation unit in the apparatus for recovering a purified 2-methylglutaronitrile.
  • the second distillation unit for the apparatus for recovering a purified DCH can be the same or similar in design, internals, configuration aspects, or a combination thereof, to the first distillation unit for the apparatus for recovering a purified 2-methylglutaronitrile.
  • the crude mixture for use in the apparatus for recovering the purified DCH can include about 65 to about 80 wt.% DCH (e.g., less than or equal to 80 wt.%, greater than or equal to about 65 wt.%, or less than, equal to, or greater than 66 wt.%, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, or 79 wt.%), about 10 to about 20 wt.% hexamethylenediamine (HMD) (e.g., less than or equal to 20 wt.%, greater than or equal to 10 wt.%, and less than, equal to, or greater than 11 wt.%, 12, 13, 14, 15, 16, 17, 18, or 19 wt.%), about 0 to 5 wt.% hexamethyleneimine (HMI) (e.g., less than or equal to 5 wt.%, greater than or equal to 0 wt.
  • the apparatus for recovering the purified DCH can include a first distillation unit configured to distill the crude mixture to produce a first bottom stream including concentrated DCH optionally including HMD, AMC, MPMD, or a combination thereof, and a first overhead stream including HMD and optionally including AMC, MPMD, or a combination thereof.
  • the first distillation unit can have a head pressure maintained in a range of 700 to 850 mmHg, or about 760 mmHg, or about atmospheric conditions, or less than or equal to 850 mmHg, greater than or equal to 700 mmHg, and less than, equal to, or greater than 710 mmHg, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, or 840 mmHg.
  • the first distillation unit can have a base pressure maintained in a range of 700 to 850 mmHg, or about 760 mmHg, or about atmospheric conditions, or less than or equal to 850 mmHg, greater than or equal to 700 mmHg, and less than, equal to, or greater than 710 mmHg, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, or 840 mmHg.
  • the head conditions of the first distillation unit can be maintained at about 130 °C to 135 °C, or less than or equal to 135 °C, greater than or equal to 130 °C, and less than, equal to, or greater than 131 °C, 132, 133, or 134 °C.
  • the base conditions of the first distillation unit can be maintained at about 185 °C to 200 °C, or less than or equal to 200 °C, greater than or equal to 185 °C, and less than, equal to, or greater than 186 °C, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, or 199 °C.
  • the first distillation unit can be configured for the crude mixture to be introduced into a lower half of the first distillation unit.
  • the first distillation unit can include two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages, or 30 to 80 stages, or less than or equal to 80, greater than or equal to 30, and less than, equal to, or greater than 35, 40, 45, 50, 55, 60, 65, 70, or 75 theoretical distillation stages.
  • the first distillation unit can be configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • the second distillation unit can have a base pressure maintained in a range of about 150 to 250 mmHg, or 210 to 225 mmHg, or less than or equal to 250 mmHg, greater than or equal to 150 mmHg, and less than, equal to, or greater than 160 mmHg, 170, 180, 190, 200, 210, 220, 230, or 240 mmHg.
  • the second distillation unit can be configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • the second distillation unit can include two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages, or 50 to 100 stages, or less than or equal to 100, greater than or equal to 50, and less than, equal to, or greater than 55, 60, 65, 70, 75, 80, 85, 90, or 95 theoretical stages.
  • the second distillation unit can be configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • the second overhead stream, the side-draw stream, or a combination thereof can be the purified DCH.
  • the side-draw stream can be obtained from a near a top section of the second distillation unit.
  • the second overhead stream, the side-draw stream, or a combination thereof, can be the purified DCH.
  • the second overhead stream can be the purified DCH.
  • the side-draw stream can be the purified DCH.
  • a combination of the second overhead stream and the side-draw stream can be the purified DCH.
  • ADN adiponitrile
  • AMC 2-(aminomethyl)- cyclopentylamine
  • CPI 2-cyanocyclopentylideneimine
  • ESN 2-ethylsuccinonitrile
  • HMD hexamethylenediamine
  • MGN 2-methylglutaronitrile
  • MPP or 3MP 3-methylpiperidine
  • 1,3-pentanediamine 13PDA
  • HMI hexamethyleneimine
  • DCH 1,2-diaminocyclohexane
  • the unit of pressure measurement one torr is equal to 1 mmHg.
  • One Psi absolute (Psia) is equal to 51.715 mmHg.
  • FIG. l is a schematic representation of two-distillation column apparatus used in the present comparative Example.
  • a distillation column system 100 as shown in FIG. 1 and similar to that described in the process of W02014210191 Al, is implemented in this comparative Example.
  • feed stream 3 includes (by weight) about 80% MGN, about 10% ESN, about 2-5% ADN, about 0.5% CPI, about 3-3.5% other nitriles, and balance ⁇ 1% (combined) other fugitive impurities, such as trivalent and pentavalent phosphorus species, glycols, phenols, cresols, catechol, trace HCN and benzene, and the like.
  • the feed stream 3 is fed to a first distillation column 111.
  • the head pressure of column I l l is maintained at about 50 mmHg (0.97 Psia) and the overhead/bottom temperatures are maintained at about 50/200 °C.
  • Column 111 distills the feed and concentrates the light components and most of the ESN in the overhead.
  • An overhead condenser (not shown in FIG. 1) condenses the column 111 overhead to obtain about 30-40% of each ESN and MGN, and light impurities totaling about 20-30% as overhead stream 7.
  • the non-condensable components from the column 111 condenser are purged with an inert gas (nitrogen) and flowed to a vent header for disposal.
  • the column 111 bottom stream 5 may constitute about 93-95% MGN, 4-6% ADN, ⁇ 1% ESN, and 0.5-1% CPI.
  • the bottom stream 5 is fed to a second distillation column 121.
  • the head pressure of column 121 is maintained at about 50 mmHg (0.97 Psia) and the overhead/bottom temperatures are maintained at about 50/200 °C.
  • Column 121 distills the bottom stream 5 and concentrates the MGN overhead.
  • An overhead condenser (not shown in FIG. 1) condenses the column 121 overhead to yield at least 99.1% purity MGN, about ⁇ 5000 ppm ESN, ⁇ 1000 ppm ADN, and about 0.5-0.6% CPI as overhead stream 9.
  • the non-condensable components in the column 121 overhead are purged with an inert gas (nitrogen) and flowed to a vent header for disposal.
  • the column 121 bottom stream 11 may contain a majority of the ADN that was present in the feed stream 3 along with some MGN and remaining CPI.
  • the CPI level in the refined MGN product i.e., overhead stream 9) is not reduced to below 5000 ppm (by weight) when the process of W02014210191 Al is employed for MGN purification in this Example.
  • the CPI in the MGN converts entirely to its reductively aminated intermediate, 2-(aminomethyl)- cyclopentylamine (AMC).
  • AMC is difficult to remove from the MPMD product.
  • the resulting refined MPMD product contains elevated levels of AMC, and therefore is not suitable in several commercial end-use applications, for example, in the manufacture of Vitamin B3 (Niacin) and in fiber applications.
  • FIG. 2 shows a schematic representation of an aspect 200 that is an improvement over that described in Example 1.
  • feed stream 32 includes (by weight) of about 85-87% MGN, about 5-8% ESN, about 3-5% ADN, about 0.5% CPI, about 1-2% other nitriles, and balance ⁇ 1% (combined) other fugitive impurities, such as trivalent and pentavalent phosphorus species, glycols, phenols, cresols, catechol, trace HCN and benzene, and the like.
  • the feed stream 32 is fed to a first distillation column 211, which is operated similarly to column 111 in Example 1.
  • the head pressure of column 211 is maintained at about 50 mmHg (0.97 Psia) and the overhead/bottom temperatures are maintained at about 50/198 °C.
  • Column 211 distills the feed and concentrates the lighter components and most of ESN in the overhead.
  • An overhead condenser (not shown in FIG. 2) condenses the column 211 overhead to obtain about 30-35% ESN, 50-55% MGN, and lighter impurities totaling about 15-20% as overhead stream 72.
  • a partial stream 163 (shown as a dotted path in FIG. 2) may be recycled back to the column 211 in such situations as the transient, start-up, and production change modes.
  • the non-condensable components from the column 211 condenser are purged with an inert gas (nitrogen) and flowed to a vent header for disposal.
  • the column 211 bottom stream 52 may constitute about 93-95% MGN, 4-6% ADN, ⁇ 1% ESN, and 0.5-1% CPI.
  • the bottom stream 52 is fed to a second distillation column 221, which is operated similarly to column 121 in Example 1.
  • the head pressure of column 221 is maintained at about 50 mmHg (0.97 Psia) and the overhead/bottom temperatures are maintained at about 50/195 °C.
  • Column 221 distills the bottom stream 52 and concentrates the MGN overhead.
  • An overhead condenser (not shown in FIG. 2) condenses the column 221 overhead to yield at least 99.1% purity MGN, about ⁇ 5000 ppm ESN, ⁇ 1000 ppm ADN, and about 0.5-0.6% CPI as overhead stream 92.
  • the non-condensable components in the column 221 overhead are purged with an inert gas (nitrogen) and flowed to a vent header for disposal.
  • the column 221 bottom stream 112 may contain a majority of the ADN that was present in the feed stream 32 along with some residual MGN and CPI.
  • a side-draw stream 97 that is rich in MGN may be taken near the top of the column 221.
  • the side-draw recovers MGN with high purity.
  • a liquid side-draw is taken, although, a vapor side-draw can also be taken.
  • the side-draw stream 97 may include at least 99.1% purity, about ⁇ 4000 ppm ESN, ⁇ 1000 ppm ADN, about ⁇ 1500 ppm CPI, and about ⁇ 1500 ppm water content.
  • Further MGN purification may be achieved by routing either a portion or the whole of the side-stream (shown as dotted path 99 in FIG. 2) along with the overhead stream 92.
  • the overhead stream 92 from the column 221 is fed to a lower half section of a third distillation column 241, which includes two or more packed sections.
  • the head pressure of column 241 is maintained at about 40 mmHg (-0.77 Psia) and the overhead/bottom temperatures are maintained at about 70/177 °C.
  • Column 241 distills the feed and concentrates the MGN overhead.
  • An overhead condenser (not shown in FIG. 2) condenses the column 241 overhead to yield at least 99.5% purity MGN, about ⁇ 5000 ppm ESN, ⁇ 1000 ppm ADN, and ⁇ 1000 ppm CPI as overhead stream 152.
  • the non-condensable components in the column 241 overhead are purged with an inert gas (nitrogen) and flowed to a vent header for disposal.
  • the column 241 bottom stream 154 may contain ADN along with some MGN and CPI.
  • the CPI level in the refined MGN product i.e., overhead stream 152 is reduced to below 1000 ppm (by weight) when the three-column configuration in FIG. 2 is employed for MGN purification.
  • FIG. 3 shows a schematic representation of a distillation system 300 used in this example.
  • a crude MGN stream 33 contains about 11% ESN, 5% ADN, about 1.5% CPI, balance MGN, and ⁇ 5000 ppm (combined) of other fugitive impurities, such as trivalent and pentavalent phosphorus species, glycols, phenols, cresols, and catechol.
  • the crude MGN feed 33 is fed to a first column 311 that houses five beds of structured packing and provides the equivalent of at least 50 theoretical distillation stages.
  • the crude feed 33 enters between the top two beds of packing.
  • the column 311 overhead that exits the top of the column contains MGN and concentrated ESN in the range of 10-90% ESN.
  • the column 311 overhead vapors are condensed in an overhead condenser (not shown in FIG. 3) with some of the condensed liquid being removed as a first overhead stream 73 and some of the liquid being used for column reflux (not shown).
  • the first column 311 normally operates at a head pressure of ⁇ 50 mmHg with an operating range of 20-100 mmHg.
  • the bottom of the first column 311 includes a forced circulation reboiler to minimize the fouling potential.
  • a thermosiphon reboiler can also be utilized.
  • the first column 311 bottom stream 53 contains the majority of MGN along with ADN, CPI, and less than 4000 ppm of ESN. This first column 311 bottom stream 53 is fed to a second column 321 for further purification.
  • the second column 321 contains four beds of structured packing with feed entering above the bottom-most bed.
  • a contact condenser is included in the column with a 5 th bed of structured packing at the top of the column 321.
  • the second column 321 normally operates at a head pressure of - 40 mmHg with an operating range of 20-100 mmHg.
  • the bottom of the second column 321 includes a forced circulation reboiler to minimize the fouling potential.
  • a thermosiphon reboiler can also be utilized.
  • the second column 321 bottom stream 113 contains MGN, ADN, and CPI.
  • the first column 311 overhead stream 73 is combined with the second column 321 bottom stream 113, and the combined tails stream 115 is flowed to a heat exchange device 331.
  • the heat exchange device 331 cools the combined tails stream 115 to a temperature range of 45-65 °C.
  • the cooled combined tails stream 117 is routed for disposal, for example, in the boilers for incineration.
  • the refined MGN product i.e., side-stream 95
  • the refined MGN product is obtained with at least 99.1% purity and contains about ⁇ 4000 ppm ESN, ⁇ 1000 ppm ADN, about ⁇ 1200 ppm CPI, and ⁇ 1200 ppm water content.
  • the distillation system 300 can be continuously operated to purify MGN without any interruptions or shutdowns.
  • the purified MGN product contains lower levels of CPI impurity when compared to that in Example 1.
  • a crude MGN stream contains about 85% MGN, 10% ESN, 3% ADN, about 1.5% CPI, and ⁇ 5000 ppm (combined) of other process impurities, such as trivalent and pentavalent phosphorus species, glycols, phenols, cresols, and catechol.
  • This crude stream is processed in the two-column distillation system as described in Example 3 and in FIG. 3.
  • the crude feed 33 is effectively fractionated in the first column 311 to MGN-enriched first column bottom stream 53 containing about 90% MGN, ⁇ 20 % ADN, ⁇ 0.5 % ESN and about 2-3% CPI.
  • the first column overhead vapors are condensed to obtain the first column overhead liquid stream 73, which concentrates ESN as approximately 30:70 ESN:MGN.
  • the first column overhead vapor stream also concentrates other incoming impurities, such as trivalent and pentavalent phosphorus species, glycols, phenols, cresols, and catechol.
  • the non-condensable overhead gaseous stream is routed to a vent header for disposal.
  • the first column bottom stream 53 is fed to the second column 321.
  • a sidedraw stream 95 taken from near the top section of second column 321, is refined MGN product of at least 99.1% purity containing about ⁇ 4000 ppm ESN, ⁇ 1000 ppm ADN, about ⁇ 1200 ppm CPI, and ⁇ 1200 ppm water content.
  • the second column bottom stream 113 accumulates the CPI along with ADN and some MGN.
  • the first column overhead liquid stream 73 is combined with the second column bottom stream 113, cooled in heat exchange device 331, and routed to the boilers for incineration.
  • the flow movement of stream 115 is continuous with no flowline blockages or process interruptions.
  • Example 6 The two-column distillation system of Example 3 is repeated, except the first column overhead liquid stream 73 is not combined with the second column bottom stream 113 before routing for disposal.
  • the CPI concentration in the second column bottom stream 113 varies between 5-20% of the total by weight. This stream causes flow line blockages, further restricting the flow. The process productivity is reduced because of these frequent process interruptions. Frequent equipment and line clean-up is needed. The process cannot be operated continuously.
  • the refined MGN product of comparative Example 1 is hydrogenated in the hydrogen and ammonia presence to produce its corresponding branched diamine, 2-methyl- pentamethylenediamine (MPMD).
  • MPMD 2-methyl- pentamethylenediamine
  • the CPI present in the hydrogenation feed converts to its corresponding amine known as 2-(aminomethyl)-cyclopentylamine (AMC). Separation of AMC from the hydrogenation reaction product is not trivial. It is disadvantageous to have high levels of CPI in the refined MGN product as feed to the hydrogenation step.
  • the refined MGN product of Example 3 is hydrogenated in the presence of hydrogen and ammonia to produce its corresponding branched diamine, 2-methyl- pentamethylenediamine (MPMD).
  • MPMD 2-methyl- pentamethylenediamine
  • This ⁇ 1200 ppm CPI containing refined MGN product is hydrogenated to yield MPMD with very low levels of 2-(aminomethyl)-cyclopentylamine (AMC). It is desirable to produce MPMD with very low levels of AMC.
  • FIG. 4 shows a schematic representation of a distillation unit 400 as used in Example 3, such as the second distillation unit 321 shown in FIG. 3.
  • the main unit components are shown, while the auxiliary components such as flowmeters, flow/temperature/pressure control equipment, in-line filters, by-pass lines, and the like, are not shown.
  • a vertical distillation unit 401 contains more than two vapor-liquid contacting sections, some of which are labeled as 403, and provide at least 30 theoretical distillation stages for separation.
  • Other suitable physical design and/or media for the vaporliquid contact can also be useful in the unit 401.
  • Some non-limiting examples are bubble cap tray sections, sieve tray sections, structured/random packed sections, and the like.
  • Unit 401 is equipped with a slide-draw pump unit 404, a side-draw heat exchange unit 405, a reflux liquid spray unit 406, a bottom sparger 407, a reboiler feed pump 408, a reboiler unit 409 and a bottom draw pump unit 410.
  • a distillation feed 471 may be produced in a step before the unit 401, such as by the first distillation unit 311 shown in FIG. 3.
  • Feed 471 may include MGN along with ADN, CPI, and less than 4000 ppm of ESN.
  • Feed 471 is pumped via a feed pump unit 402 and the pressurized feed 472 is introduced in the lower half of the unit 401. In FIG. 4 the feed introduction is shown between the two lower packed sections as an illustration.
  • the conditions in the unit 401 are maintained such as to concentrate the MGN at the overhead as the vapor-liquid contact is achieved in the packed sections.
  • the top section of unit 401 is equipped with a liquid collection stage from where the accumulated liquid may be drawn as a side-draw stream 473.
  • the side-draw stream 473 is pumped via the side-draw pump unit 404 to the side-draw heat exchanger unit 405 for cooling.
  • a portion of the side-draw pump unit 404 discharge may be routed back to the unit 401, which is shown as a return stream 474.
  • a portion of the cooled side-draw stream 475 is fed back to the unit 401 as reflux liquid stream 477.
  • the reflux liquid stream 477 is uniformly distributed across the unit 401 flow area using the reflux liquid spray unit 406.
  • the remaining cooled side-draw stream 476 is the refined MGN product of at least 99.1% purity containing about ⁇ 4000 ppm ESN, ⁇ 1000 ppm ADN, about ⁇ 1200 ppm CPI, and ⁇ 1200 ppm water content of the total mass.
  • the unit 401 bottom liquid stream 479 is pumped to the reboiler unit 409 via the reboiler feed pump 408 as a reboiler feed stream 480.
  • the liquid boil-up energy is provided in the reboiler unit 409 and a boiled-up vapor stream 481 is taken back to the unit 401 through the bottom sparger 407.
  • the reflux liquid stream 477 and the boiled-up vapor stream 481 are maintained to provide adequate hydraulic load and counter-current vaporliquid traffic in the unit 401. Care is taken not to overload the unit 401 which may cause either liquid flooding or drying of the separation space.
  • a portion of the unit 401 bottom liquid is pumped out as a bottom draw stream 482 via the bottom draw pump 410.
  • the bottom draw stream 482 contains MGN, ADN, and CPI. This stream is routed for its safe disposal, which is equivalent to the stream labeled 113 in FIG. 3.
  • a non-condensable off-gas stream 478 is drawn from the unit 401 overhead and routed to a vent header, which is equivalent to the off-gas stream labeled 93 in FIG. 3.
  • the unit 401 recovers MGN to a purity of at least 99.1% by wt., containing about ⁇ 4000 ppm ESN, ⁇ 1000 ppm ADN, about ⁇ 1200 ppm CPI, and ⁇ 1200 ppm water content of the total mass.
  • This high-purity MGN is a desirable feed for the subsequent hydrogenation to its diamine, MPMD.
  • Example 9 Referring to the process described in Example 2 and schematically represented in FIG. 2, the column 211 bottom stream 52 contains about 93-95% MGN, 4-6% ADN, ⁇ 1% ESN, and 0.5-1% CPI.
  • This MGN-containing stream 52 is cooled and hydrogenated in the presence of hydrogen and ammonia to produce its corresponding branched diamine, 2- methyl-pentamethylenediamine (MPMD).
  • MPMD 2- methyl-pentamethylenediamine
  • the ADN and ESN present in the feed convert to their respective diamines, namely, hexamethylenediamine (HMD) and 1,3-pentanediamine (13PDA).
  • the residual CPI impurity is hydrogenated to its corresponding amine, 2- (aminomethyl)-cyclopentylamine (AMC).
  • the hydrogenated product contains mainly MPMD with other components (HMD, 13PDA, AMC) in ⁇ 10 wt% of the total stream.
  • the crude hydrogenation product may be optionally refined by stripping most of the HMD and 13PDA by distillation or other separation means such as extraction, membrane separation, etc.
  • streams suitable for making semi-refined MPMD products may include stream 5 (FIG. 1), streams 53, 93, 95 (in FIG. 3) as well as streams 474 or 476 (FIG. 4).
  • This example serves as another embodiment wherein the crude MGN stream may be processed to provide semi-refined MPMD product suitable in some industrial applications that are less sensitive to the AMC impurity, for example, in epoxy curing, reactive coatings and other applications, wherein the residual AMC is not a problem.
  • FIG. 5 shows a schematic representation of a distillation unit 500 that can be utilized for the separation of another co-product stream obtained from an industrial dinitrile production facility.
  • Hexamethyleneimine (HMI) is another by-product formed in the process of adiponitrile manufacture from butadiene hydrocyanation.
  • the first column 501 may be similar to the first column 211 (in FIG. 2) or column 311 (in FIG. 3) in design, internals and configuration aspects. It may include two or more packed sections providing equivalent of about 50 to 80, for example, about 60 or 70 or 75, theoretical distillation separation stages.
  • the feed may enter at the top third section of the column 501.
  • the column 501 head/base conditions may be maintained at about 425-450 mmHg/450-475 mmHg of pressure and about 100-115 °C/110-130 °C temperature.
  • the overhead vapor stream may be partially condensed to about 40 °C.
  • the column 501 may concentrate most of the light organics including n-hexylamine and water in an overhead stream 515, while the bottoms stream 513 is a concentrated stream of HMI along with residual impurities including HMD.
  • the HMI-rich bottoms stream 513 may be taken to a second column 502 and fed near the top-middle section of the column.
  • the second column 502 may be similar to the second column 221 (in FIG. 2) or column 321 (in FIG. 3) in design, internals and configuration aspects. It may include two or more packed sections providing equivalent of about 30 to 60, for example, about 35 or 40 or 50, theoretical distillation separation stages.
  • the column 502 head/base conditions may be maintained at about 145-155 mmHg/155-165 mmHg of pressure and about 80-90 °C/130-140 °C temperature.
  • the overhead vapor stream may be partially condensed to about 45 °C.
  • the column 502 may concentrate most of the HMI in an overhead stream 517, while the bottoms stream 519 is a concentrated HMD stream along with a residual amount of HMI (as yield loss).
  • This example illustrates another industrial utilization of the disclosed method that can be operated to obtain a refined stream of HMI (CAS Registry No. 111-49-9).
  • the column operations described in Examples 2 and 3 may be customized for the refinement of HMI.
  • the HMI product is commercially available from INVISTA under the tradename Dytek® HMI amine. It can find applications in pharmaceuticals, textile chemicals, dyes, agricultural chemicals, corrosion inhibitor, inks, in zeolite manufacture, ore flotation and rubber chemicals.
  • FIG. 6 shows a schematic representation of a distillation unit 600 that can be utilized for the separation of another co-product stream obtained from an industrial dinitrile/diamine production facility.
  • 1,2-Diaminocyclohexane (DCH) is another by-product formed in the process of diamine production from dinitrile hydrogenation.
  • the column 602 may be equipped with a pump-around condenser at the very top to exchange heat and add a cooled liquid reflux to the column to cool the overhead in the 70-80°C temperature range.
  • the column 602 may concentrate most of the light organics including n-hexylamine, cyclohexylamine and HMI in an overhead stream 613, while the bottoms stream 615 is a concentrated stream of DCH along with residual impurities including HMD, AMC and MPMD.
  • the DCH-rich bottoms stream 615 may be taken to a second column in sequence, i.e., the column labeled 601, and fed near the lower-third section of the column.
  • the column 601 is similar in design, internals and configuration to the column 501 described in Example 10 and FIG. 5.
  • the column 601 may be operated under vacuum with the head/base conditions maintained at about 140-155 mmHg/210-225 mmHg of pressure and about 130-145 °C/145-160 °C temperatures.
  • the overhead vapor stream may be partially condensed to about 35 °C.
  • the column 601 may concentrate most of the DCH in an overhead stream 617, while the bottoms stream 619 is a concentrated HMD stream along with some residual DCH loss and other impurities including MPMD and AMC.
  • the column 121 base temperature conditions as well as a partial blockage of difficult-to-flow stream 11 may trigger undesirable sidereactions and may result in generation of minor amounts HCN.
  • Any HCN formed at the column base would tend to concentrate in the column 121 overhead stream 9, which is a refined product stream.
  • the HCN presence in refined overhead product is not desirable for end-uses.
  • the Example 1 method therefore, may not provide a suitable refined product quality.
  • a column side-draw such as either stream 97 (in FIG. 2) or stream 95 (in FIG.
  • about 2,000 Ibs/hr of stream 72 at about 40 °C temperature may be combined with about 900 Ibs/hr of stream 112 at about 188 °C temperature.
  • the resulting hot stream 156 may be passed through a heat exchanger to obtain a cooled combined stream of about 2,900 Ibs/hr at about ⁇ 100 °C. This organic stream may be further processed and/or treated for safe disposal.
  • Aspect 2 provides the method of Aspect 1, wherein the method is operated continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 3 provides the method of any one of Aspects 1-2, wherein the optional distilling of at least one of the second overhead stream and the side-draw stream in the third distillation unit is not performed, and wherein the second overhead stream, the side-draw stream, or a combination thereof, is the purified 2-methylglutaronitrile.
  • Aspect 4 provides the method of Aspect 3, wherein the second overhead stream is the purified 2-methylglutaronitrile.
  • Aspect 5 provides the method of Aspect 3, wherein the side-draw stream is the purified 2-methylglutaronitile.
  • Aspect 6 provides the method of Aspect 3, wherein a combination of the second overhead stream and the side-draw stream is the purified 2-methylglutaronitrile.
  • Aspect 7 provides the method of any one of Aspects 1-6, wherein the crude mixture further comprises ⁇ 5 wt.% phenols and cresols, ⁇ 10 wt.% water, ⁇ 2 wt.% pentenenitrile, ⁇ 0.2 wt.% boronate esters or glycols, ⁇ 100 ppm by wt. hydrogen cyanide, and ⁇ 100 ppm by wt. benzene of the total crude mixture mass.
  • Aspect 8 provides the method of any one of Aspects 1-7, wherein the distilling the crude mixture in the first distillation unit comprises introducing the crude mixture into an upper half of the first distillation unit.
  • Aspect 9 provides the method of any one of Aspects 1-8, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 10 provides the method of any one of Aspects 1-9, wherein the distilling the first bottom stream in the second distillation unit comprises introducing the first bottom stream into a lower half of the second distillation unit.
  • Aspect 11 provides the method of any one of Aspects 1-10, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 12 provides the method of any one of Aspects 1-11, wherein the method comprises passing process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the first overhead stream and to provide a first noncondensed vapor purge material.
  • Aspect 13 provides the method of any one of Aspects 1-12, wherein the method comprises passing process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 14 provides the method of any one of Aspects 1-13, further comprising cooling the tail mixture to a temperature of 40-60 °C in a heat exchange device.
  • Aspect 15 provides the method of any one of Aspects 1-14, wherein the head pressure of the first distillation unit is in a range of 40 to 60 mmHg.
  • Aspect 16 provides the method of any one of Aspects 1-15, wherein the head pressure of the second distillation unit is in a range of 40 to 60 mmHg.
  • Aspect 17 provides the method of any one of Aspects 1-16, wherein overhead and bottom temperatures in the first distillation unit are maintained in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 18 provides the method of any one of Aspects 1-17, wherein overhead and bottom temperature in the second distillation unit are maintained in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 19 provides the method of any one of Aspects 1-18, wherein the method comprises obtaining the side-draw stream from near a top section of the second distillation unit.
  • Aspect 20 provides the method of any one of Aspects 1-19, wherein the optional distilling of at least one of the second overhead stream and the side-draw stream in the third distillation unit is performed, and wherein the third overhead stream is the purified 2-methylglutaronitrile.
  • Aspect 21 provides the method of Aspect 20, wherein an overhead and bottom temperatures in the third distillation unit are maintained in ranges of 55-80 °C and 160-190 °C, respectively.
  • Aspect 22 provides the method of any one of Aspects 20-21, wherein the head pressure of the third distillation unit is in a range of 30 to 50 mmHg.
  • Aspect 23 provides the method of any one of Aspects 20-22, wherein the distilling at least one of the second overhead stream and the side-draw stream comprises introducing at least one of the second overhead stream and the side-draw stream to a lower half of the third distillation unit.
  • Aspect 24 provides the method of any one of Aspects 20-23, wherein the third distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 25 provides the method of any one of Aspects 20-24, wherein the method comprises passing process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the third overhead stream and to provide a third non-condensed vapor purge material.
  • Aspect 26 provides a method of recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture comprising about 70 to about 90 wt.% 2- methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities, the method comprising: distilling the crude mixture in a first distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream comprising ⁇ 1 wt.% 2- ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream comprising ⁇ 1 wt.% adiponitrile of a total first overhead stream mass; distilling the first bottom stream in a second distillation unit having a head pressure in
  • Aspect 27 provides the method of Aspect 26, wherein the method is operated continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 28 provides the method of any one of Aspects 26-27, wherein the second overhead stream is the purified 2-methylglutaronitrile.
  • Aspect 29 provides the method of any one of Aspects 26-27, wherein the sidedraw stream is the purified 2-methylglutaronitile.
  • Aspect 30 provides the method of any one of Aspects 26-27, wherein a combination of the second overhead stream and the side-draw stream is the purified 2- methylglutaronitrile.
  • Aspect 31 provides the method of any one of Aspects 26-30, wherein the crude mixture further comprises ⁇ 5 wt.% phenols and cresols, ⁇ 10 wt.% water, ⁇ 2 wt.% pentenenitrile, ⁇ 0.2 wt.% boronate esters or glycols, ⁇ 100 ppm by wt. hydrogen cyanide, and ⁇ 100 ppm by wt. benzene of the total crude mixture mass.
  • Aspect 32 provides the method of any one of Aspects 26-31, wherein the distilling the crude mixture in the first distillation unit comprises introducing the crude mixture into an upper half of the first distillation unit.
  • Aspect 33 provides the method of any one of Aspects 26-32, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 34 provides the method of any one of Aspects 26-33, wherein the distilling the first bottom stream in the second distillation unit comprises introducing the first bottom stream into a lower half of the second distillation unit.
  • Aspect 35 provides the method of any one of Aspects 26-34, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 37 provides the method of any one of Aspects 26-36, wherein the method comprises passing process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 38 provides the method of any one of Aspects 26-37, further comprising cooling the tail mixture to a temperature of 40-60 °C in a heat exchange device.
  • Aspect 39 provides the method of any one of Aspects 26-38, wherein the head pressure of the first distillation unit is in a range of 40 to 60 mmHg.
  • Aspect 40 provides the method of any one of Aspects 26-39, wherein the head pressure of the second distillation unit is in a range of 40 to 60 mmHg.
  • Aspect 41 provides the method of any one of Aspects 26-40, wherein overhead and bottom temperatures in the first distillation unit are maintained in ranges of 45- 60 °C and 190-205 °C, respectively.
  • Aspect 42 provides the method of any one of Aspects 26-41, wherein overhead and bottom temperature in the second distillation unit are maintained in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 43 provides the method of any one of Aspects 26-42, wherein the method comprises obtaining the side-draw stream from near a top section of the second distillation unit.
  • Aspect 44 provides a method of recovering a purified 2-methylglutaronitrile from a crude mixture, the crude mixture comprising about 70 to about 90 wt.% 2- methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities, the method comprising: distilling the crude mixture in a first distillation unit having a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream comprising ⁇ 1 wt.% 2- ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream comprising ⁇ 1 wt.% adiponitrile of a total first overhead stream mass; distilling the first bottom stream in a second distillation unit having a head pressure in
  • Aspect 45 provides the method of Aspect 44, wherein the method is operated continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 46 provides the method of any one of Aspects 44-45, wherein the crude mixture further comprises ⁇ 5 wt.% phenols and cresols, ⁇ 10 wt.% water, ⁇ 2 wt.% pentenenitrile, ⁇ 0.2 wt.% boronate esters or glycols, ⁇ 100 ppm by wt. hydrogen cyanide, and ⁇ 100 ppm by wt. benzene of the total crude mixture mass.
  • Aspect 48 provides the method of any one of Aspects 44-47, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 49 provides the method of any one of Aspects 44-48, wherein the distilling the first bottom stream in the second distillation unit comprises introducing the first bottom stream into a lower half of the second distillation unit.
  • Aspect 50 provides the method of any one of Aspects 44-49, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 56 provides the method of any one of Aspects 44-55, wherein overhead and bottom temperatures in the first distillation unit are maintained in ranges of 45- 60 °C and 190-205 °C, respectively.
  • Aspect 57 provides the method of any one of Aspects 44-56, wherein overhead and bottom temperature in the second distillation unit are maintained in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 58 provides the method of any one of Aspects 44-57, wherein the method comprises obtaining the side-draw stream from near a top section of the second distillation unit.
  • Aspect 60 provides the method of any one of Aspects 44-59, wherein the head pressure of the third distillation unit is in a range of 30 to 50 mmHg.
  • Aspect 61 provides the method of any one of Aspects 44-60, wherein the distilling at least one of the second overhead stream and the side-draw stream comprises introducing at least one of the second overhead stream and the side-draw stream to a lower half of the third distillation unit.
  • Aspect 62 provides the method of any one of Aspects 44-61, wherein the third distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 63 provides the method of any one of Aspects 44-62, wherein the method comprises passing process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the third overhead stream and to provide a third non-condensed vapor purge material.
  • Aspect 64 provides a method of recovering a purified hexamethyleneimine (HMI) from a crude mixture, the crude mixture comprising about 80 to about 90 wt.% HMI, about 5 to about 15 wt.% n-hexylamine, about 0 to 5 wt.% water, about 0 to 5 wt.% cyclohexylamine, and about 0 to about 5 wt.% hexamethylenediamine (HMD), the method comprising: distilling the crude mixture in a first distillation unit having a head pressure in a range of 400 to 500 mmHg to produce a first bottom stream comprising concentrated HMI comprising HMD, and a first overhead stream comprising n-hexylamine and optionally comprising water; distilling the first bottom stream in a second distillation unit having a head pressure in a range of 100 to 200 mmHg to produce a second bottom stream comprising concentrated HMD comprising HMI; and obtaining at least one of
  • Aspect 65 provides the method of Aspect 64, wherein the second overhead stream is the purified HMI.
  • Aspect 67 provides the method of Aspect 64, wherein a combination of the second overhead stream and the side-draw stream is the purified HMI.
  • Aspect 69 provides the method of any one of Aspects 64-68, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 70 provides the method of any one of Aspects 64-69, wherein the distilling the first bottom stream in the second distillation unit comprises introducing the first bottom stream into an upper half of the second distillation unit.
  • Aspect 71 provides the method of any one of Aspects 64-70, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 73 provides the method of any one of Aspects 64-72, wherein the method comprises passing process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 74 provides the method of any one of Aspects 64-73, wherein the head pressure of the first distillation unit is in a range of 425 to 450 mmHg.
  • Aspect 75 provides the method of any one of Aspects 64-74, wherein the head pressure of the second distillation unit is in a range of 145 to 155 mmHg.
  • Aspect 76 provides the method of any one of Aspects 64-75, wherein overhead and bottom temperatures in the first distillation unit are maintained in ranges of 110-115 °C and 110-130 °C, respectively.
  • Aspect 77 provides the method of any one of Aspects 64-76, wherein overhead and bottom temperature in the second distillation unit are maintained in ranges of 80-90 °C and 130-140 °C, respectively.
  • Aspect 78 provides the method of any one of Aspects 64-77, wherein the method comprises obtaining the side-draw stream from near a top section of the second distillation unit.
  • Aspect 79 provides the method of any one of Aspects 64-78, wherein the purified HMI is 99 wt.% to 99.9 wt.% HMI.
  • Aspect 80 provides the method of any one of Aspects 64-79, wherein the purified HMI is less than or equal to 0.40 wt.% cyclohexylamine, less than or equal to 0.02 wt.% n-hexylamine, less than or equal to 0.07 wt.% water, and less than or equal to 0.02 wt.% HMD.
  • Aspect 82 provides the method of Aspect 81, wherein the second overhead stream is the purified DCH.
  • Aspect 83 provides the method of Aspect 81, wherein the side-draw stream is the purified DCH.
  • Aspect 84 provides the method of Aspect 81, wherein a combination of the second overhead stream and the side-draw stream is the purified DCH.
  • Aspect 85 provides the method of any one of Aspects 81-84, wherein the distilling the crude mixture in the first distillation unit comprises introducing the crude mixture into a lower half of the first distillation unit.
  • Aspect 86 provides the method of any one of Aspects 81-85, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 87 provides the method of any one of Aspects 81-86, wherein the distilling the first bottom stream in the second distillation unit comprises introducing the first bottom stream into a lower half of the second distillation unit.
  • Aspect 88 provides the method of any one of Aspects 81-87, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 89 provides the method of any one of Aspects 81-88, wherein the method comprises passing process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the first overhead stream and to provide a first noncondensed vapor purge material.
  • Aspect 90 provides the method of any one of Aspects 81-89, wherein the method comprises passing process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condensing the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 91 provides the method of any one of Aspects 81-90, wherein the head pressure of the first distillation unit is about 760 mmHg.
  • Aspect 92 provides the method of any one of Aspects 81-91, wherein the head pressure of the second distillation unit is in a range of 145-155 mmHg.
  • Aspect 93 provides the method of any one of Aspects 81-92, wherein overhead and bottom temperatures in the first distillation unit are maintained in ranges of 130-135 °C and 185-200 °C, respectively.
  • Aspect 94 provides the method of any one of Aspects 81-93, wherein overhead and bottom temperature in the second distillation unit are maintained in ranges of 130-145 °C and 145-160 °C, respectively.
  • Aspect 95 provides the method of any one of Aspects 81-94, wherein the method comprises obtaining the side-draw stream from near a top section of the second distillation unit.
  • Aspect 96 provides the method of any one of Aspects 81-95, wherein the purified DCH is 98.5-99.9 wt.% DCH.
  • Aspect 97 provides the method of any one of Aspects 81-96, wherein the purified DCH is less than or equal to 0.1 wt.% 2-methylpentamethylenediamine, less than or equal to 0.1 wt.% hexamethylenediamine, and less than or equal to 0.1 wt.% water.
  • Aspect 98 provides an apparatus for recovering a purified 2- methylglutaronitrile from a crude mixture, the crude mixture comprising about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities, the apparatus comprising: a first distillation unit configured to distill the crude mixture at a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream comprising ⁇ 1 wt.% 2- ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream comprising ⁇ 1 wt.% adiponitrile of a total first overhead stream mass; a second distillation unit configured to distill the first bottom stream at a head pressure in
  • Aspect 99 provides the apparatus of Aspect 98, wherein the apparatus is operatable continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 100 provides the apparatus of any one of Aspects 98-99, wherein the optional third distillation unit is not present, and wherein the second overhead stream, the side-draw stream, or a combination thereof, is the purified 2-methylglutaronitrile.
  • Aspect 102 provides the apparatus of Aspect 100, wherein the side-draw stream is the purified 2-methylglutaronitile.
  • Aspect 103 provides the apparatus of Aspect 100, wherein a combination of the second overhead stream and the side-draw stream is the purified 2-methylglutaronitrile.
  • Aspect 104 provides the apparatus of any one of Aspects 98-103, wherein the crude mixture further comprises ⁇ 5 wt.% phenols and cresols, ⁇ 10 wt.% water, ⁇ 2 wt.% pentenenitrile, ⁇ 0.2 wt.% boronate esters or glycols, ⁇ 100 ppm by wt. hydrogen cyanide, and ⁇ 100 ppm by wt. benzene of the total crude mixture mass.
  • Aspect 105 provides the apparatus of any one of Aspects 98-104, wherein the first distillation unit is configured for the crude mixture to be introduced into an upper half of the first distillation unit.
  • Aspect 106 provides the apparatus of any one of Aspects 98-105, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 107 provides the apparatus of any one of Aspects 98-106, wherein the second distillation unit is configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • Aspect 108 provides the apparatus of any one of Aspects 98-107, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 109 provides the apparatus of any one of Aspects 98-108, wherein the first distillation unit is configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • Aspect 110 provides the apparatus of any one of Aspects 98-109, wherein the second distillation unit is configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 111 provides the apparatus of any one of Aspects 98-110, further comprising a heat exchange device configured to cool the tail mixture to a temperature of 40- 60 °C.
  • Aspect 112 provides the apparatus of any one of Aspects 98-111, wherein the first distillation unit is configured to distill the crude mixture at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 113 provides the apparatus of any one of Aspects 98-112, wherein the second distillation unit is configured to distill the first bottom stream at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 114 provides the apparatus of any one of Aspects 98-113, wherein the first distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 115 provides the apparatus of any one of Aspects 98-114, wherein the second distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 116 provides the apparatus of any one of Aspects 98-115, wherein the second distillation unit is configured to provide the side-draw stream from near a top section of the second distillation unit.
  • Aspect 117 provides the apparatus of any one of Aspects 98-116, wherein the third distillation unit is present, and wherein the third overhead stream is the purified 2- methylglutaronitrile.
  • Aspect 118 provides the apparatus of Aspect 117, wherein the third distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 55-80 °C and 160-190 °C, respectively.
  • Aspect 119 provides the apparatus of any one of Aspects 117-118, wherein the third distillation unit is configured to distill the at least one of the second overhead stream and the side-draw stream at a head pressure of in a range of 30 to 50 mmHg.
  • Aspect 120 provides the apparatus of any one of Aspects 117-119, wherein the third distillation unit is configured for the at least one of the second overhead stream and the side-draw stream to be introduced to a lower half of the third distillation unit.
  • Aspect 121 provides the apparatus of any one of Aspects 117-120, wherein the third distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 122 provides the apparatus of any one of Aspects 117-121, wherein the third distillation unit is configured to pass process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and to condense the process vapors to provide a liquid which is the third overhead stream and to provide a third non-condensed vapor purge material.
  • Aspect 123 provides an apparatus for recovering a purified 2- methylglutaronitrile from a crude mixture, the crude mixture comprising about 70 to about 90 wt.% 2-methylglutaronitrile, about 1 to about 20 wt.% 2-ethylsuccinonitrile, about 1 to 15 wt.% adiponitrile, about 0.05 to about 5 wt.% 2-cyanocyclopentylideneimine, and about 0.01 to about 2 wt.% other impurities, the apparatus comprising: a first distillation unit configured to distill the crude mixture at a head pressure in a range of 20 to 100 mmHg to produce a first bottom stream comprising ⁇ 1 wt.% 2- ethylsuccinonitrile of the total first bottom stream mass, and a first overhead stream comprising ⁇ 1 wt.% adiponitrile of a total first overhead stream mass; a second distillation unit configured to distill the first bottom stream at a head pressure in
  • Aspect 124 provides the apparatus of Aspect 123, wherein the apparatus is operatable continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 125 provides the apparatus of any one of Aspects 123-124, wherein the second overhead stream is the purified 2-methylglutaronitrile.
  • Aspect 126 provides the apparatus of any one of Aspects 123-125, wherein the side-draw stream is the purified 2-methylglutaronitile.
  • Aspect 127 provides the apparatus of any one of Aspects 123-126, wherein a combination of the second overhead stream and the side-draw stream is the purified 2- methylglutaronitrile.
  • Aspect 129 provides the apparatus of any one of Aspects 123-128, wherein the first distillation unit is configured for the crude mixture to be introduced into an upper half of the first distillation unit.
  • Aspect 131 provides the apparatus of any one of Aspects 123-130, wherein the second distillation unit is configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • Aspect 132 provides the apparatus of any one of Aspects 123-131, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 133 provides the apparatus of any one of Aspects 123-132, wherein the first distillation unit is configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • Aspect 134 provides the apparatus of any one of Aspects 123-133, wherein the second distillation unit is configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 135 provides the apparatus of any one of Aspects 123-134, further comprising a heat exchange device configured to cool the tail mixture to a temperature of 40- 60 °C.
  • Aspect 136 provides the apparatus of any one of Aspects 123-135, wherein the first distillation unit is configured to distill the crude mixture at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 137 provides the apparatus of any one of Aspects 123-136, wherein the second distillation unit is configured to distill the first bottom stream at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 138 provides the apparatus of any one of Aspects 123-137, wherein the first distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 139 provides the apparatus of any one of Aspects 123-138, wherein the second distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 140 provides the apparatus of any one of Aspects 123-139, wherein the second distillation unit is configured to provide the side-draw stream from near a top section of the second distillation unit.
  • Aspect 142 provides the apparatus of Aspect 141, wherein the apparatus is operatable continuously with less than five flow interruptions from the tail mixture per year of operation.
  • Aspect 143 provides the apparatus of any one of Aspects 141-142, wherein the crude mixture further comprises ⁇ 5 wt.% phenols and cresols, ⁇ 10 wt.% water, ⁇ 2 wt.% pentenenitrile, ⁇ 0.2 wt.% boronate esters or glycols, ⁇ 100 ppm by wt. hydrogen cyanide, and ⁇ 100 ppm by wt. benzene of the total crude mixture mass.
  • Aspect 144 provides the apparatus of any one of Aspects 141-143, wherein the first distillation unit is configured for the crude mixture to be introduced into an upper half of the first distillation unit.
  • Aspect 145 provides the apparatus of any one of Aspects 141-144, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 146 provides the apparatus of any one of Aspects 141-145, wherein the second distillation unit is configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • Aspect 147 provides the apparatus of any one of Aspects 141-146, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 149 provides the apparatus of any one of Aspects 141-148, wherein the second distillation unit is configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 150 provides the apparatus of any one of Aspects 141-149, further comprising a heat exchange device configured to cool the tail mixture to a temperature of 40- 60 °C.
  • Aspect 151 provides the apparatus of any one of Aspects 141-150, wherein the first distillation unit is configured to distill the crude mixture at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 152 provides the apparatus of any one of Aspects 141-151, wherein the second distillation unit is configured to distill the first bottom stream at a head pressure in a range of 40 to 60 mmHg.
  • Aspect 153 provides the apparatus of any one of Aspects 141-152, wherein the first distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 154 provides the apparatus of any one of Aspects 141-153, wherein the second distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 45-60 °C and 190-205 °C, respectively.
  • Aspect 155 provides the apparatus of any one of Aspects 141-154, wherein the second distillation unit is configured to provide the side-draw stream from near a top section of the second distillation unit.
  • Aspect 156 provides the apparatus of any one of Aspects 151-155, wherein the third distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 55-80 °C and 160-190 °C, respectively.
  • Aspect 157 provides the apparatus of any one of Aspects 151-156, wherein the third distillation unit is configured to distill the at least one of the second overhead stream and the side-draw stream at a head pressure of in a range of 30 to 50 mmHg.
  • Aspect 158 provides the apparatus of any one of Aspects 151-157, wherein the third distillation unit is configured for the at least one of the second overhead stream and the side-draw stream to be introduced to a lower half of the third distillation unit.
  • Aspect 159 provides the apparatus of any one of Aspects 151-158, wherein the third distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 160 provides the apparatus of any one of Aspects 151-159, wherein the third distillation unit is configured to pass process vapors from a top of the third distillation unit overhead to a third condensing device maintained at a condensing temperature and to condense the process vapors to provide a liquid which is the third overhead stream and to provide a third non-condensed vapor purge material.
  • Aspect 161 provides an apparatus for recovering a purified hexamethyleneimine (HMI) from a crude mixture, the crude mixture comprising about 80 to about 90 wt.% HMI, about 5 to about 15 wt.% n-hexylamine, about 0 to 5 wt.% water, about 0 to 5 wt.% cyclohexylamine, and about 0 to about 5 wt.% hexamethylenediamine (HMD), the apparatus comprising: a first distillation unit configured to distill the crude mixture at a head pressure in a range of 400 to 500 mmHg to produce a first bottom stream comprising concentrated HMI comprising HMD, and a first overhead stream comprising n-hexylamine and optionally comprising water; and a second distillation unit configured to distill the first bottom stream at a head pressure in a range of 100 to 200 mmHg to produce a second bottom stream comprising concentrated HMD comprising HMI, wherein the second distillation unit
  • Aspect 162 provides the apparatus of Aspect 161, wherein the second overhead stream is the purified HMI.
  • Aspect 163 provides the apparatus of Aspect 161, wherein the side-draw stream is the purified HMI.
  • Aspect 164 provides the apparatus of Aspect 161, wherein a combination of the second overhead stream and the side-draw stream is the purified HMI.
  • Aspect 165 provides the apparatus of any one of Aspects 161-164, wherein the first distillation unit is configured for the crude mixture to be introduced into an upper half of the first distillation unit.
  • Aspect 166 provides the apparatus of any one of Aspects 161-165, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 167 provides the apparatus of any one of Aspects 161-166, wherein the second distillation unit is configured for the first bottom stream to be introduced into an upper half of the second distillation unit.
  • Aspect 168 provides the apparatus of any one of Aspects 161-167, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 169 provides the apparatus of any one of Aspects 161-168, wherein the first distillation unit is configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • Aspect 170 provides the apparatus of any one of Aspects 161-169, wherein the second distillation unit is configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 171 provides the apparatus of any one of Aspects 161-170, wherein the first distillation unit is configured to distill the crude mixture at a head pressure in a range of 425 to 450 mmHg.
  • Aspect 172 provides the apparatus of any one of Aspects 161-171, wherein the second distillation unit is configured to distill the first bottom stream at a head pressure in a range of 145 to 155 mmHg.
  • Aspect 173 provides the apparatus of any one of Aspects 161-172, wherein the first distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 110-115 °C and 110-130 °C, respectively.
  • Aspect 174 provides the apparatus of any one of Aspects 161-173, wherein the second distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 80-90 °C and 130-140 °C, respectively.
  • Aspect 175 provides the apparatus of any one of Aspects 161-174, wherein the second distillation unit is configured to provide the side-draw stream from near a top section of the second distillation unit.
  • Aspect 176 provides the apparatus of any one of Aspects 161-175, wherein the purified HMI is 99 wt.% to 99.9 wt.% HMI.
  • Aspect 177 provides the apparatus of any one of Aspects 161-176, wherein the purified HMI is less than or equal to 0.40 wt.% cyclohexylamine, less than or equal to 0.02 wt.% n-hexylamine, less than or equal to 0.07 wt.% water, and less than or equal to 0.02 wt.% HMD.
  • Aspect 178 provides an apparatus for recovering a purified 1,2- diaminocyclohexane (DCH) from a crude mixture, the crude mixture comprising about 65 to about 80 wt.% DCH, about 10 to about 20 wt.% hexamethylenediamine (HMD), about 0 to 5 wt.% hexamethyleneimine (HMI), about 0 to about 5 wt.% 2-(aminomethyl)- cyclopentylamine (AMC), about 0 to about 5 wt.% 2-methyl-pentamethylenediamine (MPMD), and about 0 to about 2 wt.% other impurities comprising n-hexylamine, cyclohexylamine, or a combination thereof, the apparatus comprising: a first distillation unit configured to distill the crude mixture at a head pressure in a range of 700 to 850 mmHg to produce a first bottom stream comprising concentrated DCH optionally comprising HMD, AMC, MP
  • Aspect 179 provides the apparatus of Aspect 178, wherein the second overhead stream is the purified DCH.
  • Aspect 180 provides the apparatus of Aspect 178, wherein the side-draw stream is the purified DCH.
  • Aspect 181 provides the apparatus of Aspect 178, wherein a combination of the second overhead stream and the side-draw stream is the purified DCH.
  • Aspect 182 provides the apparatus of any one of Aspects 178-181, wherein the first distillation unit is configured for the crude mixture to be introduced into a lower half of the first distillation unit.
  • Aspect 183 provides the apparatus of any one of Aspects 178-182, wherein the first distillation unit comprises two or more packed sections that together provide an equivalent of at least 30 total theoretical distillation stages.
  • Aspect 184 provides the apparatus of any one of Aspects 178-183, wherein the second distillation unit is configured for the first bottom stream to be introduced into a lower half of the second distillation unit.
  • Aspect 185 provides the apparatus of any one of Aspects 178-184, wherein the second distillation unit comprises two or more packed sections that together provide an equivalent of at least 50 total theoretical distillation stages.
  • Aspect 186 provides the apparatus of any one of Aspects 178-185, wherein the first distillation unit is configured to pass process vapors from a top of the first distillation unit to a first condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the first overhead stream and to provide a first non-condensed vapor purge material.
  • Aspect 187 provides the apparatus of any one of Aspects 178-186, wherein the second distillation unit is configured to pass process vapors from a top of the second distillation unit to a second condensing device maintained at a condensing temperature and condense the process vapors to provide a liquid which is the second overhead stream and to provide a second non-condensed vapor purge material.
  • Aspect 189 provides the apparatus of any one of Aspects 178-188, wherein the second distillation unit is configured to distill the first bottom stream at a head pressure in a range of 145-155 mmHg.
  • Aspect 190 provides the apparatus of any one of Aspects 178-189, wherein the first distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 130-135 °C and 185-200 °C, respectively.
  • Aspect 191 provides the apparatus of any one of Aspects 178-190, wherein the second distillation unit is configured to maintain overhead and bottom temperatures therein in ranges of 130-145 °C and 145-160 °C, respectively.
  • Aspect 192 provides the apparatus of any one of Aspects 178-191, wherein the second distillation unit is configured to provide the side-draw stream from near a top section of the second distillation unit.
  • Aspect 193 provides the apparatus of any one of Aspects 178-192, wherein the purified DCH is 98.5-99.9 wt.% DCH.
  • Aspect 194 provides the apparatus of any one of Aspects 178-193, wherein the purified DCH is less than or equal to 0.1 wt.% 2-methylpentamethylenediamine, less than or equal to 0.1 wt.% hexamethylenediamine, and less than or equal to 0.1 wt.% water.
  • Aspect 195 provides a method of recovering a purified material from a crude mixture, the method comprising: distilling the crude mixture in a first distillation unit having a head pressure to produce a first bottom stream, and a first overhead stream; distilling the first bottom stream in a second distillation unit having a head pressure to produce a second bottom stream; and obtaining at least one of a second overhead stream and a side-draw stream from the second distillation unit; wherein the second overhead stream, the side-draw stream, or a combination thereof, is the purified material; wherein the method is a method of recovering a purified hexamethyleneimine (HMI) from the crude mixture, the crude mixture comprising about 80 to about 90 wt.% HMI, about 5 to about 15 wt.% n-hexylamine, about 0 to 5 wt.% water, about 0 to 5 wt.% cyclohexylamine, and about 0 to about 5 wt.% hexamethylened
  • Aspect 196 provides an apparatus for recovering a purified material from a crude mixture, the apparatus comprising: a first distillation unit configured to distill the crude mixture at a head pressure to produce a first bottom stream and a first overhead stream; and a second distillation unit configured to distill the first bottom stream at a head pressure to produce a second bottom stream, wherein the second distillation unit is configured to provide at least one of a second overhead stream and a side-draw stream; wherein the apparatus is for recovering a purified hexamethyleneimine (HMI) from a crude mixture, the crude mixture comprising about 80 to about 90 wt.% HMI, about 5 to about 15 wt.% n-hexylamine, about 0 to 5 wt.% water, about 0 to 5 wt.% cyclohexylamine, and about 0 to about 5 wt.% hexamethylenediamine (HMD), the head pressure of the first distillation unit is maintained in a range of 400 to 500
  • Aspect 197 provides the method or apparatus of any one or any combination of Aspects 1-196 optionally configured such that all elements or options recited are available to use or select from.

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  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

La présente divulgation concerne un procédé et un appareil de récupération d'une substance purifiée à partir d'un mélange brut, par exemple pour récupérer un 2-méthylglutaronitrile purifié à partir d'un mélange brut obtenu à partir d'un processus de fabrication de nitriles industriels.
PCT/IB2025/051793 2024-02-21 2025-02-19 Récupération de substance purifiée à partir d'un mélange brut Pending WO2025177178A2 (fr)

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Citations (1)

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Publication number Priority date Publication date Assignee Title
WO2014210191A1 (fr) 2013-06-26 2014-12-31 Invista Technologies S.A R.L. Procédé amélioré pour le raffinage de nitriles

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US10759741B2 (en) * 2013-07-17 2020-09-01 Invista North America S.A R.L. Separating a solvent from a nickel catalyst by distillation

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Publication number Priority date Publication date Assignee Title
WO2014210191A1 (fr) 2013-06-26 2014-12-31 Invista Technologies S.A R.L. Procédé amélioré pour le raffinage de nitriles

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no. 694-83-7

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