TW200301250A - Purification method of (meth)acrylic acid ester - Google Patents

Abstract

In a process for producing a methacrylic ester by esterifying methacrylic acid and an alcohol in the presence of an acid catalyst, a purification step is conducted which comprises rectifying the reaction mixture in the presence of a heteroatom-containing chelate complex with the central metal an element in groups 7 to 12 of a long period in the periodic table to thereby inhibit alcohol production through a transesterification between the methacrylic ester and the hydroxy compound thereof which is a by-product present as an impurity; thus, a high-purity methacrylic ester can be produced.

Description

200301250 [Technical field to which the invention belongs] The present invention relates to a method for purifying acrylate or methacrylate (hereinafter, acrylic acid and methacrylic acid are collectively referred to as "(meth) acrylic acid"), and more specifically, the present invention It is related to the reaction of inhibiting the occurrence of alcohol by adding a specific chelating compound to the crude (meth) acrylate purified product obtained through the esterification reaction step and the steps of neutralization, washing and removal of low boiling point components. An industrially useful purification method for obtaining high-purity (meth) acrylic acid. [Prior art] Conventionally, '(meth) acrylate is widely used as a monomer component for manufacturing coating agents and adhesives, and even optical materials such as contact lenses. These acrylates are mainly produced by esterification of acrylic acid obtained by contact oxidation of propane or propylene; and methacrylates can be produced by: acetone cyanhydrin method, new Acetone cyanohydrin method, or contact oxidation method using isobutene and tert-butanol as raw materials, to directly produce 'methyl methacrylate obtained by these methods through esterification, or methyl methacrylate obtained directly from these methods The ester is produced by transesterification. Among them, a method of producing (meth) acrylic acid and an alcohol by an esterification reaction in the presence of an acid catalyst is widely used. In this manufacturing method, a step of removing the acid catalyst and unreacted (meth) acrylic acid from the obtained esterification reaction solution (the main component is (meth) acrylate) after the reaction is required. This is a method for treating the esterification reaction solution with an alkaline aqueous solution (Japanese Patent Laid-Open No. Sho 6 3-9 9 0 3 7, 6 312 / Invention Specification (Supplement) / 92-03 / 91135277 200301250 6 1-2 4 3 ο 4 Gazette 6 etc.). However, with these methods alone, the acid catalyst cannot be completely removed. Therefore, the following problem arises: if it is necessary to obtain a high-purity (meth) acrylate, rectification is performed from a (meth) acrylate reaction solution containing a trace amount of an acid catalyst, and unreacted alcohol and by-products are removed. Removal of the '(meth) acrylic acid ester produces an alcohol due to the transesterification reaction between the hydrocarbon-based compound of the by-products in the rectification step and the (meth) acrylic acid ester, resulting in the purity of the (meth) acrylic acid ester. reduce. [Summary of the Invention] The present invention has been made by providing a method for efficiently producing a high-purity (meth) acrylate, which can overcome the problems and solve the problems in the conventional manufacturing method as described above. Problems that occur during the rectification step. The present inventors have conducted various reviews in order to solve the problems described above, and found that, in the (meth) acrylate purification step, if an acid catalyst coexists in the (meth) acrylate reaction solution, then The hydrocarbyl compounds of the by-products undergo transesterification with (meth) acrylates to produce alcohols. Based on this knowledge, the acid catalyst can be removed by adding a specific chelate compound 'to the (meth) acrylate reaction solution, and the above-mentioned object can be achieved, and the present invention was achieved by 焉. That is, the gist of the present invention is a method for purifying a (meth) acrylate, which is characterized in that a (meth) acrylate containing an impurity is chelated to a complex compound containing a heteroatom to have a Distillation is performed in the presence of Group 18 element periodic table (long period periodic table) Groups 7 to 12 as the central metal) to prevent (meth) propylene 7 mixed in the product. Pieces) / 92-03 / 91135277 200301250 The occurrence of alcohols in esters. [Embodiment] Hereinafter, the present invention will be described in detail. As a method for producing a (meth) acrylic acid ester, a (meth) acrylic acid and an alcohol, or a (meth) acrylic acid ester and an alcohol of a lower aliphatic alcohol are generally used in an esterification catalyst. It is heated to react in the presence of water, and the generated water or lower alcohol is reacted under azeotropic distillation with an organic solvent outside the reaction system. As a target (meth) acrylate, it can be distilled by zero. The purified low-boiling compounds are distilled / purified after the reaction is completed, and the high-boiling compounds that cannot be distilled are removed after the reaction is completed. The esterification catalyst is removed by alkali or acid solution. Can be used as esters of interest. ~ The distillation solution provided by the present invention may be: an esterification reaction solution, a solution obtained by removing high-boiling impurities or low-boiling impurities from the esterification reaction solution through distillation, a solution obtained by washing with acid or alkali, or a concentrated solution thereof Either solution. As the above-mentioned esterification catalysts, acid catalysts such as sulfuric acid, phosphoric acid, methane, cristobalic acid, benzene expansion acid, p-benzenesulfonic acid, and strongly acidic cation exchange resins are generally used. The distillation of the present invention may be: distillation of (meth) acrylic acid esters to remove high boiling point impurities, or distillation of low boiling point impurities; however, the (meth) acrylic acid in the present invention The rectification step of the ester can be carried out, preferably the reaction,

The step is 312 / Invention Specification (Supplement) / 92-03 / 91135277 8 200301250. The medium is taken from the 4 steps of separation, neutralization, washing steps, and subsequent steps of separation of low-boiling components such as unreacted gardenia. The reaction solution was further purified by distillation under reduced pressure to separate high-boiling components from the top of the column to obtain purified (meth) acrylate. Examples of the (meth) acrylate in the present invention include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and the like, and methyl acrylate, Acrylates such as ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. Among these, butyl acrylate and ethyl ethylhexyl acrylate are particularly preferred. The heteroatom-containing chelate complex used in the present invention to form an organic dissociation constant (ρ κ a) of an organic ligand of the complex is 4.3 or more. In the following cases', the acid catalyst cannot be sufficiently removed, and the desired effect cannot be obtained. Specific examples of the heteroatom-containing chelate coordination compound of the organic ligand having an acid dissociation constant of 4.3 or more include, for example, bis (acetamidine) manganese (II), bis (Acetoacetone) Iron (11), Bis (Acetoacetone) Cobalt (I1), Bis (Acetoacetone) Nickel (II), Bis (Acetoacetone) Copper (II), Bis (Acetoacetone) Zinc (Industrial I), Bis (2-aminoethanol) copper (Industrial), Bis (2-aminoethanol) Nickel (Industrial I), Bis (2-aminoethanol) Zinc (Industrial), Bis (2-aminoamino) Thiol) cobalt (II), bis (2-aminoethylthiol) copper (I), bis (2-aminoethylthiol) zinc (II), bis (imidazole) copper (II), bis (imidazole) Nickel (II), bis (imidazole) zinc (II), bis (ethylenediamine) copper (construction), bis (ethylenediamine) iron (1 1), bis (ethylenediamine) manganese (work I), Bis (ethylenediamine) nickel 9 312 / Invention manual (Supplement) Ship 03/91135 Tear 200301250 (worker), bis (ethylene monoamine) zinc (worker), bis (catechol) cobalt (i work) , Bis (catechol) copper (II), bis (catechol) Iron (Ϊ J), bis (catechol) manganese (Σ 1), bis (catechol) nickel (II), bis (catechol) zinc (i Ϊ), bis (malonate) copper (industrial) ), Bis (picric acid) copper (II), bis (2, 2-dipyridyl) copper (J), bis (salicylic acid) copper (I), bis (aminoacetic acid) copper (II) )Wait. In addition to the above, as the particularly preferred chelate complex compound, a heteroatom-containing chelate complex compound represented by the following general formula (1) may be mentioned:

(In the formula, M represents a metal atom of Groups 7 to 12 of the periodic table of the group elements; R 1 and R 2 represent the same or different, and may be a monovalent or divalent aliphatic hydrocarbon group or aromatic group bonded to each other. Hydrocarbon group, heteroatom group). The so-called Group 18 element periodic table (long-periodic periodic table) of the 7th to 12th squares of the original metal are specific and hundred, and examples include Mn, Fe, Co, Ni, Cu, Zn, and the like. Among these, Cu is preferred. R 1 and R 2 are the same or different, and may be a monovalent or = valent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heteroatom group bonded to each other. The above-mentioned aliphatic hydrocarbon group means a saturated or unsaturated, linear, branched or cyclic substituted monovalent or divalent aliphatic hydrocarbon group having 1 to 1 carbon atoms. Examples of the substituent of the aliphatic hydrocarbon group include aromatic hydrocarbon groups such as benzene-tolyl. Specific examples include: substituted or unsubstituted linear hydrocarbon groups such as methyl, benzyl, ethyl, n-propyl, butyl, n-hexyl, and the like; isocyanide 3] 2 / Invention Specification (Supplement Pieces) / 92-03 / 91135277 200301250 branched hydrocarbon groups such as isobutyl; cyclic hydrocarbon groups such as cyclohexyl; divalent aliphatic hydrocarbon groups such as methylene (methylene), vinyl, and propenyl, etc. . The divalent aliphatic hydrocarbon group may be a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms formed by bonding to each other. Specific examples include tetramethylidene, pentamethylidene, hexamethylidene, and the like. The above-mentioned aromatic hydrocarbon group means a monovalent or divalent aromatic hydrocarbon group which may be substituted with 6 to 10 carbon atoms. Examples of the substituent of the aromatic hydrocarbon group include an aliphatic hydrocarbon group such as a methyl group and an ethyl group, a methoxy group such as a methoxy group, and a carbonyl group such as an ethanoyl group. Specific examples of the aromatic hydrocarbon group include phenyl, naphthyl, tolyl, xylyl, and the like. This aromatic hydrocarbon group may be bonded to each other to form a divalent aromatic hydrocarbon group such as a divalent aromatic group. The heteroatom group is preferably a divalent heteroatom chain crosslinked by R1 and R2 via an oxygen atom, a nitrogen atom, or the like. Specific examples include — · Methoxyethylene and the like. Preferred examples of the heteroatom-containing chelate coordination compound of the present invention include bis (dimethyldithioaminoformate) copper (1 1), and bis (diethyldithioamine). Methyl formate) copper (I), bis (di-n-propyl dithiocarbamate) copper (II), bis (diisopropyl dithiocarbamate) copper (1 1), bis (di-n-propyl Butyl dithiocarbamate) copper (II), bis (diisobutyl dithiocarbamate) copper (I), bis (dihexyl dithiocarbamate) copper (1 1), Copper (II) bis (dicyclohexyldithiocarbamate), copper (I) bis (diphenyldithiocarbamate), copper (bis (dibenzyldithiocarbamate)) 1), bis (di312 / Invention Specification (Supplement)) / 92-03 / 9113 5277 11 200301250 morpholinyl dithiocarbamic acid) copper (11), bis (monopiperidinyl-monoaminocarbamic acid) ) Copper (II), bis (di-D-pyridyl)-monothioaminomethyl I) copper (1 work), etc. Although the addition amount of the heteroatom-containing chelate complex compound in the present invention varies depending on the residual catalyst concentration in the (meth) acrylic acid ester supplied to the rectification step, generally, the acid catalyst concentration, In theory, Q · 5 times ears is sufficient. However, if the amount of addition is small, the removal of the acid catalyst will be incomplete, and if the amount of addition is large, the precipitation of inorganic compounds will occur at the bottom of the rectification column, which will cause clogging, which is not good. Therefore, the preferred range of the addition amount is 0.6 to 3 times the mole, especially 0.9 to 3 times the mole. The distillation temperature in the present invention can be appropriately selected depending on the corresponding (meth) acrylate. For example, in the case of butyl acrylate, 80 ° C ~ 100 ° C is usually selected. In the case of ethyl cyclohexyl ester, a range of 100 ° C to 140 ° C is usually selected. The reaction time is usually set to 0.2 to 2 hours. If it is shorter than this, the removal of the acid catalyst is incomplete, and if it is too long, it is economically meaningless. The method for adding the heteroatom-containing chelate complex is not particularly limited. For example, a method of directly adding the (meth) acrylate remaining in the bottom of the column after the removal of the low-boiling point component, or the reflux (meth) acrylate liquid of the distillation distillate after rectification, and using A method of dissolving and adding an appropriate solvent. The addition temperature can also be appropriately determined. < Examples > Hereinafter, examples will be described in more detail. 312 / Instruction of the Invention (Supplement) / 92-03 / 91135277 12 20030IE50 (Synthesis of propionic acid 2-ethylhexyl vinegar crude product) The purity of propionic acid obtained by the contact oxidation method of propionic acid is 9 9. 6% by weight of crude acrylic acid 778.39 (10.8 ^: 1), 2-ethylhexanol 1 17 2 · 1 g (9 · 0 m〇1), and 390 g of toluene as a solvent were added as The catalyst of 39 g of p-toluenesulfonic acid and hydroquinone as a polymerization inhibitor made it 100 ppm by weight of the total solution to a 3 L reactive distillation flask with a refined column. The esterification reaction was performed under the conditions of a flask temperature of 95 ° C and a reaction time of 14 hours. After the completion of the esterification reaction, distilled water equivalent to 0.1 in weight ratio to the esterification reaction solution was added, and extraction and removal of the residual catalyst through the distilled water was performed. This operation was repeated three times to recover the organic layer to obtain a crude 2-ethylhexyl acrylate. The obtained reaction product contained: 2-6% ethylhexyl acrylate 86% by weight, hydrocarbyl propionate 2-ethylhexyl ester 1.8% by weight, and 2-ethylhexanol 0 · 0 0 1 weight %, P-toluenesulfonic acid: 0.001% by weight, and other high boiling point components of about 12 · 2% by weight. (Example 1) 30 g of the crude 2-ethylhexyl acrylate obtained above, p-toluenesulfonic acid present in the system, and iso-mole bis (di-n-butylthioamino acid) were weighed separately. Copper (II) was placed in a container with an internal volume of 100 m 1 with a thermocouple and a gas injection tube. The container was immersed in an oil bath, and air was blown into the liquid at a speed of 15 m 1 / min. As a result of gas chromatography analysis performed every i hours, it was found that 2-ethylhexanol increased Q · 0 10 0% by weight after i hour of heating, and 8-hours later for 2-ethylhexanol. No increase was seen in the concentration. 13 1 10,000 Description of the Invention (Supplement) / 92-03 / 91135277 200301250 (Comparative Example 1) Except that bis (di-n-butylthiocarbamic acid) copper (jj) was not added, the same as in Example 1 1 In the same way, under the heat test, after 1 hour from the start of heating, it's increased by 0 · 0 5 ◦ wt%, and the concentration of 2-ethylhexanol reached 0 · at the end of the next 8 hours of heating. 4% by weight. (Example 2) Except for adding bis (di-n-butylaminocarbamate) copper (II) at 0.5 times mole of p-toluene acid, 'under a heating test in the same manner as in Example 1' The concentration of 2-ethylhexanol at the end of heating for 8 hours was 0. 0 9 Q% by weight. This alcohol concentration is an allowable range as a product. The foregoing description of the present invention has been made in detail with reference to specific embodiments. As long as various changes can be made without departing from the spirit and scope of the present invention, it is self-evident to the practitioner. This application is based on a Japanese patent application filed on May 5, 2001 (Japanese Patent Application Nos. 2001-37 7 i 95), and the contents are incorporated herein by reference. Industrially available items are as described above. According to the present invention, in the purification step in the (meth) acrylate production method, the (meth) acrylate and the hydrocarbon-based compound (which exist as impurities) The side reaction product) is used to inhibit the production of alcohols by transesterification reaction. 'High-purity (meth) acrylic acid ester can be produced, so it has great value in industry. 14 312 / Invention Specification (Supplement) / 92-03 / 91135277

Claims (1)

200301250 Patent application scope 1 · A method for purifying (meth) acrylic acid esters, characterized in that (meth) acrylic acid esters containing impurities are chelated complex compounds containing heteroatoms (for Distillation is performed in the presence of elements of Groups 7 to 12 of the Periodic Table of Elements as the central metal). 2 · Purification method of (meth) acrylic acid ester according to item 1 of the scope of patent application, which is prepared by esterification of (meth) acrylic acid (meth) acrylic acid and alcohol in the presence of an acid catalyst . 3. Purification method of (meth) acrylic acid esters as in item i or 2 of the scope of patent application 'wherein' (meth) acrylic acid esters containing impurities are the presence of (meth) acrylic acid and alcohols in the presence of acid catalysts A crude (meth) acrylate obtained by performing an esterification reaction and neutralizing, washing, and removing low-boiling components in the following steps. 4 · Purification method of (meth) acrylic acid esters according to any one of the items 1 to 3 of the scope of the patent application: The (meth) acrylic acid ester (meth) acrylic acid is in contact with 2 monoethyl cyclohexanol The catalyst is obtained by performing esterification reaction in the presence of p-toluenesulfonic acid. 5. The method for purifying (meth) acrylic acid esters according to any one of claims 1 to 4, wherein the chelate coordination compound containing a hetero atom is used to form an organic coordination of the coordination compound The acid dissociation constant (p} ca) of the group is 4 · 3 or more. 6. The purification method of (meth) acrylic acid vinegar according to any one of claims 1 to 5, wherein the chelate coordination compound containing a hetero atom is a compound represented by the following general formula (1): 312 / Invention Specification (Supplement) / 92-03 / 91135277 200301250 (In the formula, M represents a metal atom of Group 7 to Group 12 of the periodic table of the type 18 element; R 1 and R 2 represent the same or different, and may be a monovalent or divalent aliphatic hydrocarbon group bonded to each other, Aromatic hydrocarbon group, heteroatom group). 7. The method for purifying (meth) acrylic acid esters according to any one of claims 1 to 6, wherein the (meth) acrylic acid esters containing impurities contain a hydrocarbon-based compound and p-toluenesulfonic acid as an acid catalyst. acid. 16 312 / Invention Specification (Supplement) / 92-03 / 91135277 200301250 Lu, (1), the designated representative figure in this case is: Figure _ (B), the component representative symbol of this representative figure is simply explained: and J \\\柒 If there is a chemical formula in this case, please disclose the chemical formula that can best show the characteristics of the invention: Charm 312 / Invention Specification (Supplement) / 92-03 / 91135277 4