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EP0724554A1 - Procede de production de trichlorotrifluoroethanes - Google Patents

Procede de production de trichlorotrifluoroethanes

Info

Publication number
EP0724554A1
EP0724554A1 EP94927219A EP94927219A EP0724554A1 EP 0724554 A1 EP0724554 A1 EP 0724554A1 EP 94927219 A EP94927219 A EP 94927219A EP 94927219 A EP94927219 A EP 94927219A EP 0724554 A1 EP0724554 A1 EP 0724554A1
Authority
EP
European Patent Office
Prior art keywords
fluorination
product
ratio
isomerization
catalyst
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.)
Withdrawn
Application number
EP94927219A
Other languages
German (de)
English (en)
Inventor
Velliyur Nott Mallikarjuna Rao
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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 EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0724554A1 publication Critical patent/EP0724554A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C19/00—Acyclic saturated compounds containing halogen atoms
    • C07C19/08—Acyclic saturated compounds containing halogen atoms containing fluorine
    • C07C19/10—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine
    • C07C19/12—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine having two carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
    • C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
    • C07C17/202—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction
    • C07C17/206—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction the other compound being HX
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/35—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction
    • C07C17/358—Preparation of halogenated hydrocarbons by reactions not affecting the number of carbon or of halogen atoms in the reaction by isomerisation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

  • This invention relates to a process for the manufacture of C 2 CI3F3 reaction product from a mixture of C2CI 4 F2 isomers, and more particularly to the manufacture of C2CI3F3 reaction product which is substantially free of CC1F CC1F 2 .
  • Tetrachlorodifluoroethanes are readily converted to trichlorotrifluoroethanes (C2CI3F3) by using conventional fluorination.
  • the C2CI3F3 product typically contains greater than 98% of the more symmetrical isomer, CCI 2 FCCIF 2 (CFC-113) .
  • CFC-113 can be readily isomerized to its more unsymmetrical isomer, CCI 3 CF 3 (CFC-113a) using aluminum trihalide catalys .
  • CFC-113a can in turn be converted to 1, 1-dichlorotetrafluoroethane (i.e., CCI 2 FCF3 or CFC-114a) by conventional fluorination.
  • CCI 2 FCF3 is of interest as an intermediate to
  • 1,1, 1,2-tetrafluoroethane i.e., CF3CH2F or HFC-134a
  • HFC-134a is an environmentally acceptable potential replacement for chlorofluorocarbon (i.e., CFC) refrigerants, blowing agents, aerosol propellants and sterilants that are being viewed with concern in connection with the destruction of stratospheric ozone.
  • 1, 1-dichlorotetrafluoroethane employed in the hydrogenolysis route to HFC-134a has as low a content of 1,2-dichlorotetrafluoroethane (i.e., CCIF2CCIF2 or CFC-114) as practicable since the presence of CFC-114 during hydrogenolysis can lead to formation of 1, 1,2,2-tetrafluoroethane (i.e., CHF 2 CHF 2 or HFC-134; see e.g., J. L. Bitner et al., U.S. Dep. Comm. Off. Tech. Serv. Rep. 136732, (1958), p. 25) .
  • HFC-134 mixed in HFC-134a may be objectionable for some applications depending on concentration and, since the two isomers boil only 7°C apart, separation of the isomers in high purity is difficult .
  • a process for producing a reaction product comprising C 2 CI3F3 substantially free of 1, 2-dichlorotetrafluoro- ethane.
  • the process comprises the steps of (i) contacting a feed mixture consisting essentially of compounds of the formula C2Cl _ x F 2 -t (where x is 0 or 1) wherein the C 2 CI 4 F 2 content is between about 10 mole percent and 90 mole percent of said C2CI 4 - X F 2 + and wherein the mole ratio of the total amount of CCI2FCCI2F and CCI2FCCIF2 (i.e., the more symmetric C 2 CI - X F2+ X isomers) to the total amount of CCI3CCIF 2 and CCI3CF3 (i.e., the more unsymmetric C2CI 4 - X F2+ isomers) is at least about 1:9, with an isomerization catalyst to produce isomerization product
  • FIG. 1 is a schematic representation of an embodiment of this invention.
  • the process of this invention involves the vapor- phase catalytic fluorination of a mixture of tetra- chlorodifluoroethane isomers.
  • CCI2FCCIF 2 reaction product substantially free of CCIF 2 CCIF 2 is produced.
  • the C2CI 4 F 2 is present in the mixture of halogenated hydrocarbons used in the fluorination step in a molar ratio of CFC-112 to CFC-112a from about 19:1 to 1:19.
  • the ratio of CFC-112 to CFC-112a is less than about 1:1, and more preferably is less than about 1:9.
  • the fluorination is under conditions where there is no substantial production of CCIF2CCIF2 (e.g., at an elevated temperature no higher than about 400°C) .
  • No substantial production of CCIF2CCIF2 means herein that the molar ratio of CCIF2CCIF2 to CCI2FCCIF2 in the fluorination product is less than about 1:9.
  • the molar ratio of CCIF2CCIF2 to CCI2FCCIF2 in the fluorination product is less than about 1:19, and more preferably is less than about 1:99.
  • the fluorination process according to the present invention can be conducted batchwise, but is preferably conducted continuously in a manner generally known to the art for conducting catalyzed vapor phase fluorination reactions.
  • the C2CI 4 F2 mixtures are reacted with hydrogen fluoride using a catalyst comprising trivalent chromium.
  • a catalyst comprising trivalent chromium can include other components to increase catalyst activity and/or life such as one or more divalent metal ions (e.g., zinc, mangesium, and/or cobalt) .
  • the trivalent chromium catalyst may be unsupported (e.g., Cr 2 ⁇ 3) or supported (e.g., on alumina, aluminum fluoride, magnesium fluoride or carbon) .
  • Suitable vapor-phase fluorination catalysts include trivalent chromium halides (e.g., CrCl 3 and/or CrF3) supported on carbon.
  • a preferred catalyst is CrF3 on carbon and is disclosed in U.S. Pa.t. No. 3,632,834, the contents 'of which are incorporated herein by reference. While any suitable carbon support may be used, a preferred carbon support is acid-washed prior to depositing trivalent chromium on it.
  • Suitable trivalent chromium catalysts may be prepared by treating the carbon used as catalyst support with an acid, preferably with two acids .
  • the support is washed with deionized water after acid treatment and dried; and the chromium halide is then deposited thereon using deposit techniques well known in the art (see e.g.. Example 1 of U.S. 3,632,834) .
  • the chromium content (expressed as CrCl3) is from about 5 to 50 weight percent of the carbon-supported catalyst.
  • Acid treatment typically uses an acid other than hydrofluoric acid.
  • Preferred acids used for the acid treatment contain neither'phosphorus nor sulfur.
  • acids which may be used in the first acid wash during the catalyst preparation process include organic acids such as acetic acid and inorganic acids, such as HC1 or HNO 3 .
  • Preferably hydrochloric acid or nitric acid is used.
  • the second acid treatment when employed, advantageously uses hydrofluoric acid. Normally, the carbon is treated with acid such that after such treatment the carbon contains less than about 0.1% by weight ash.
  • the carbon support can be in the form of powder, granules, extrudates, or pellets, etc.
  • the acid treatment may be accomplished in several ways.
  • a suitable procedure is as follows.
  • a carbon support is soaked overnight with gentle stirring in a 1 molar solution of the acid prepared in deionized water.
  • the carbon support is then separated and washed with deionized water until the pH of the washings is about 3.
  • the carbon support is then soaked again with gentle stirring in a 1 molar solution of the acid prepared in deionized water for 12 to 24 hours.
  • the carbon support is then finally washed with deionized water until the washings are substantially free of the anion of the acid (e.g., Cl ⁇ or NO 3 -) , when tested by standard procedures.
  • the carbon support is then separated and dried at about 120°C.
  • the washed carbon is then soaked, if necessary, in 1 molar HF prepared in deionized water for about 48 hours at room temperature with occasional stirring.
  • the carbon support is separated and washed repeatedly with deionized water until the pH of the washings is greater than 4.
  • the carbon support is then dried followed by calcination at about 300°C for about 3 hours in air prior to its use as a support.
  • U.S. Patent No. 5,136,113 for further details relating to producing acid-washed carbon catalysts .
  • the fluorination is generally conducted in the reaction zone for the fluorination.
  • the reaction zone may contain more than one reactor, multiple feed lines, as well as interstage cooling or heating, addition of reactants, diluents, recycle streams, etc.
  • multiple reactors may be used to stage the degree of fluorination so that undue temperature rise and overfluorination are avoided.
  • the reaction product is normally recovered at the end of the reaction zone. If necessary, the reaction products, intermediates and/or by-products can be removed at various stages of the reaction zone and if desired recycled to different parts of the reaction zone.
  • HF and C2CI4F 2 can be fed . to a reaction zone at more than one feed location.
  • CCI 2 FCCIF 2 CFC-113
  • Suitable fluorination reaction temperatures are normally from about 250°C to 400°C.
  • a preferred temperature range is from 275°C to 375°C, with temperatures ranging from 300°C to 350°C being particularly preferred.
  • the HF to C 2 CI 4 F 2 ratio is normally from 0.2:1 to 4:1, and preferably ranges from 0.25:1 to 2:1.
  • Pressure is not critical. Atmospheric and superatmospheric pressures (e.g., from about 100 kPa to about 7000 kPa) are the most convenient and are therefore preferred.
  • the product mixture from fluorination normally contains a mixture of C2CI3F3 (almost exclusively CCI2FCCIF 2 ) small amounts of CCIF2CF3 (CFC-115) , CCIF2CCIF2, CCI2FCF3 (CFC-114a), unreacted C2CI4F2 isomers and HF and HC1.
  • the fluorination product is separated such that a portion of the C2CI3F3 (and any C 2 CI 2 F 4 ) in the product mixture is separated from C 2 CI 4 F 2 therein.
  • conventional separation using one or more distillation column (s) is employed.
  • the separation may also include one or more decanter(s) .
  • the lower boiling materials e.g., HF, HC1, CFC-115.
  • the CFC-112 isomers e.g., HF, HC1, CFC-115.
  • azeotropes of HF with various halocarbons such as CCI 2 FCCI 2 F, CCI3CCIF 2 , CCI3CF3, and CCI 2 FCF 3 can form during distillation.
  • the CFC-112 isomers from the fluorination product (which are normally enriched in CFC-112 as a result of selective fluorination of CFC-112a) and a portion of the CFC-113 isomer from the fluorination product are fed along with additional CFC-112 to an isomerization zone, where the CFC-112 is substantially converted to CFC-112a.
  • HF should be removed from the C2CI 4 F2 prior to contact with the isomerization catalyst .
  • the C 2 CI3F3 present in the mixture of C2CI3F3 and C2CI 4 F 2 fed to the isomerizer provides a melting point below the melting point of CCI2FCCI2F, thereby facilitating the desired isomerization.
  • the C2CI4F2 content is between about 10 mole percent and 75 mole percent of the C 2 CI 4 - F2 +X fed to the isomerization step; and more preferably the C2CI 4 F2 content is between about 10 mole percent and 50 mole percent thereof.
  • the CFC-112 is isomerized to CFC-112a in the presence of recycled
  • the molar ratio of C2CI 4 F2 to C2CI3F3 fed to the isomerization zone is at least about 1:9.
  • the molar ratio of (CCI 2 FCCIF 2 + CCI 2 FCCI2F) to (CCI3CF3 + CCI3CCIF2) in the compounds fed to the isomerization generally at least about 1:9.
  • Many aluminum trihalide catalysts can be employed.
  • a preferred catalyst is an anhydrous aluminum trichloride which has been micropulverized (i.e., mechanically comminuted by crushing, ball milling, rod milling, grinding or the like) to provide a surface area of greater than about 0.8 m 2 /g 'and has been activated by treatment under agitation with at least about 10 g CCI 2 FCCIF 2 per gram of aluminum trichloride.
  • micropulverized i.e., mechanically comminuted by crushing, ball milling, rod milling, grinding or the like
  • the CFC-112a is recycled in accordance with this invention to the fluorination step.
  • the CFC-113 recovered from the separation zone also may be isomerized to CFC-113a using the aluminum chloride catalyst as disclosed in Example I of U.S. Pat. No. 2,598,411.
  • preferred catalysts include an activated micropulverized anhydrous aluminum trichloride with a surface area of greater than about 0.8 m /g.
  • the CFC-113a from the isomerization zone can readily be reacted with HF in a reaction zone to afford high purity CFC-114a.
  • the latter compound can then be converted by hydrogenolysis to CH 2 FCF3 (HFC-134a) , a non-ozone depleting refrigerant.
  • FIG. 1 Employment of the instant invention is further illustrated by reference to FIG. 1 wherein a mixture of C2CI 4 F2 isomers containing substantial CFC-112 and optionally C 2 CI3F3 isomers containing substantial CFC-113 (i.e., the ratio of CFF-113 to CFC-113a is greater than 100:1) is fed through line (211) to an isomerizer (210) .
  • the isomerizer effluent consisting of a mixture of C2CI 4 F2 isomers containing predominantly CFC-112a and optionally C2CI3F3 isomers containing predominantly CFC-113a is fed through line (212) to a fluorination reactor (220) .
  • HF is fed to reactor (220) through line (221) .
  • the fluorination reactor effluent containing unreacted CCI 2 FCCIF2, unreacted C2CI4F2, HF and HC1 and optionally C 2 CI 2 F isomers containing predominantly CCI 2 FCF3 is fed through line (222) to a distillation column (230) .
  • a mixture of C 2 CI3F3 isomers, HF and HC1 and optionally C 2 CI2F 4 isomers is collected at the top of the column and recovered through line (232) .
  • the reactors and their associated feed lines, effluent lines and associated units should be constructed of materials resistant to hydrogen fluoride, hydrogen chloride and chlorine.
  • Typical materials of construction, well-known to the fluorination art include stainless steels, in particular of the austenitic type, and the well-known high nickel alloys, such as Monel® nickel-copper alloys, Hastelloy® nickel- based alloys and, Inconel® nickel-chromium alloys.
  • Also suitable for reactor fabrication are such polymeric plastics as polytrifluorochloroethylene and polytetrafluoroethylene, generally used as linings. Practice of the invention will become further apparent from the following non-limiting examples. EXAMPLES
  • a 5/8" (1.58 cm) I.D. Inconel® nickel alloy reactor was charged with a catalyst and heated to 300°C in a flow of nitrogen (25 L/min) for about 20 hours. The temperature was reduced to 175°C and a 2:1 molar ratio of nitrogen and HF was started through the reactor (total flow 100 mL/min) . After one hour under these conditions, the molar ratio of nitrogen to HF was adjusted to 1:3 and the temperature increased gradually over a two hour period to 400°C. The reactor was then brought to the desired operating temperature, the nitrogen flow stopped, and the flow of reactants started.
  • the reactor effluent was sampled on-line with a Hewlett Packard HP 5890 gas chromatograph using a 20 foot (6.1 m) long, one-eighth inch (0.32 cm) diameter, column containing KrytoxTM perfluorinated polyether on an inert support and a helium flow of 35 mL/min. Gas chromatographic conditions were 70°C for three minutes followed by temperature programming to 180°C at a rate of 6°C/minute. The table percentages are in mole% .
  • ⁇ a >115 is CC1F 2 CF 3
  • (b) 114 is CCIF2CCIF2
  • (d) 113 is CC1 2 FCC1F 2
  • (e) 113a is CCI3CF3
  • C2CI 4 F2 cannot be distinguished using the above analytical method.
  • the product consists essentially of CC1 2 FCC1 2 F) .
  • 112/a is CCI2FCCI2F + CCI3CCIF2 (The isomers of C 2 CI 4 F 2 cannot be distinguished using the above analytical method. In this example it is believed that the product consisted essentially of CCI3CCIF2) .

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

L'invention concerne un procédé de production d'un produit de réaction contenant du C2Cl3F3 sensiblement exempt de 1,2-dichlorotétrafluoroéthane. Le procédé consiste à mettre en contact un mélange d'alimentation constitué essentiellement de composés de la formule C2Cl4-xF2+x (dans laquelle x est égal à 0 ou à 1), où la teneur en C2Cl4F2 se situe entre environ 10 pour-cent en moles et 90 pour-cent en moles dudit C2Cl4-xF2+x et où le rapport molaire de la quantité totale de CCl2FCCl2F et de CCl2FCClF2 sur la quantité totale de CCl3CClF2 et de CCl3CF3 est d'au moins environ 1 : 9, avec un catalyseur d'isomérisation, pour produire un produit d'isomérisation dans lequel il y a moins de 50.000 parties en poids environ du total de CCl2FCCl2F et de CCl2FCClF2, par million de parties du poids total de CCl3CClF2 et de CCl3CF3. Le produit d'isomérisation est mis en contact avec du HF en phase vapeur en présence d'un catalyseur de fluoration comprenant du chrome trivalent, à une température élevée inférieure à 400 °C et choisie pour fournir un produit de fluoration contenant du C2Cl2F4, du C2Cl3F3 et entre environ 10 et 90 pour-cent de C2Cl4F2, provenant du produit d'isomérisation, et dans lequel le rapport de CCl2FCCl2F sur CClF2 et le rapport de CCl2FCClF2 sur CCl3F3 sont tous deux supérieurs aux rapports correspondants dans le produit d'isomérisation, et le rapport molaire de CClF2CClF2 sur CCl2FCClF2 est inférieur à environ 1 : 9. Le C2Cl2F4 et une première partie du C2Cl3F3 du produit de fluoration sont récupérés; et le C2Cl4F2 ainsi qu'une seconde partie du C2Cl3 du produit de fluoration sont récupérés; et le C2Cl4F2 et une seconde portion C2Cl3F3 du produit de fluoration sont recyclés dans l'étape d'isomérisation avec une quantité additionnelle de CCl2FCCl2F qui est au moins égale à la quantité de C2Cl2F4 et de C2Cl3 récupérée dans le produit de fluoration, et qui est suffisante pour avoir le rapport souhaité de C2Cl4F2 sur C2Cl4-xF2-x dans le mélange d'alimentation.
EP94927219A 1993-11-01 1994-09-01 Procede de production de trichlorotrifluoroethanes Withdrawn EP0724554A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US14767793A 1993-11-01 1993-11-01
US147677 1993-11-01
PCT/US1994/009532 WO1995012565A1 (fr) 1993-11-01 1994-09-01 Procede de production de trichlorotrifluoroethanes

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EP0724554A1 true EP0724554A1 (fr) 1996-08-07

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EP94927219A Withdrawn EP0724554A1 (fr) 1993-11-01 1994-09-01 Procede de production de trichlorotrifluoroethanes

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EP (1) EP0724554A1 (fr)
JP (1) JPH09504544A (fr)
WO (1) WO1995012565A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5446216A (en) * 1993-11-01 1995-08-29 E. I. Du Pont De Nemours And Company Process for manufacture of high purity 1,1-dichlorotetrafluoroethane
GB0513421D0 (en) 2005-06-30 2005-08-03 Glaxosmithkline Biolog Sa Vaccines

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA931978A (en) * 1968-01-24 1973-08-14 Frank J. Christoph, Jr. Process for preparing trichlorotrifluoroethane and dichlorotetrafluoroethane
CA2012792A1 (fr) * 1989-06-14 1990-12-14 Robert C. Zawalski Procede de preparation de chlorofluorocarbures par l'entremise d'un catalyseur a base de trihalogenure d'aluminium active genere in situ et produits en resultant

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9512565A1 *

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Publication number Publication date
JPH09504544A (ja) 1997-05-06
WO1995012565A1 (fr) 1995-05-11

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