Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives
  • C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
  • C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation

Definitions

• the present invention relates to a method for purifying an acrylic acid ester or a methacrylic acid ester (hereinafter, acrylic acid and methacrylic acid are collectively referred to as “(meth) acrylic acid”). Is to suppress the alcohol generation reaction by adding a specific chelate compound to the crudely purified (meth) acrylate ester obtained through the esterification reaction step and the neutralization / washing / light-boiling point component removal step.
• the present invention relates to an industrially advantageous purification method for obtaining high-purity (meth) acrylic acid. Background technology>
• (meth) acrylic acid esters have been widely used as monomer components for producing coating materials, adhesives, and optical materials such as contact lenses.
• acrylates are mainly produced by esterifying acrylic acid obtained by catalytic oxidation of propane or propylene, and methacrylates are obtained by the acetone cyanohydrin method, new acetate. It can be directly produced by the tonocyanhydrin method, a contact oxidation method using isobutene or t-butyl alcohol as a raw material, the methacrylic acid obtained by these methods can be esterified, and the methacrylic acid obtained directly by these methods can be obtained. It is produced by ester exchange of methyl.
• a method of producing by subjecting (meth) acrylic acid and an alcohol to an esterification reaction in the presence of an acid catalyst is generally widely used.
• An object of the present invention is to provide a method for overcoming the problems in the conventional production method, solving the problems occurring in the rectification step, and efficiently obtaining a high-purity (meth) acrylate ester. It was made for the purpose of.
• the present inventors have conducted various studies to solve the above problems, and as a result, in the (meth) acrylic acid ester purification step, when an acid catalyst coexists in the (meth) acrylic acid ester reaction solution, It was found that the hydroxy compound and the (meth) acrylate ester caused a transesterification reaction to produce alcohol, and based on this finding, by adding a specific chelate compound to the (meth) acrylate ester reaction solution, The inventors have found that the acid catalyst can be removed and the above-mentioned object can be achieved, and the present invention has been achieved.
• the gist of the present invention is that a (meth) acrylic acid ester containing impurities is a heteroatom containing a group 18-type element periodic table (long-periodic type periodic table) having a group 7-12 element as a central metal.
• This is a method for purifying (meth) acrylic acid esters, characterized in that rectification in the presence of a chelate complex suppresses the generation of alcohol mixed in the product (meth) atacrylic acid ester.
• (meth) acrylic acid ester As a method for producing (meth) acrylic acid ester, generally, (meth) acrylic acid and alcohols or (meth) acrylic acid ester of lower aliphatic alcohol and alcohols are used as an esterification catalyst.
• the reaction is carried out by heating in the presence of water, and the resulting water or lower alcohol is reacted with an organic solvent while azeotropically distilling out of the reaction system, and the desired (meth) acrylate can be purified by distillation
• purify by distillation after completion of the reaction and for non-distillable high boiling compounds, remove and discard the esterification catalyst by washing with an acid or an acid solution after the completion of the reaction, discard and concentrate. This is a method for obtaining the desired esters.
• the solution to be subjected to the distillation of the present invention may be any solution, such as a solution obtained by removing a high boiling point impurity or a low boiling point impurity from an esterification reaction solution, an esdelation reaction solution, a solution after washing with an acid or an alkaline solution, or And a concentrated solution of the solution.
• an acid catalyst such as sulfuric acid, phosphoric acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and a strongly acidic cation exchange resin has been used.
• the distillation of the present invention may be any of distillation for removing high-boiling impurities by distilling (meth) acrylic acid ester or distillation for removing low-boiling impurities.
• the acid ester rectification step is preferably for a low-boiling compound that can be purified by the above-mentioned distillation. Specifically, (meth) acrylic acid and an alcohol are subjected to an esterification reaction in the presence of an acid catalyst.
• the reaction solution obtained through the acid catalyst extraction / separation step, neutralization / washing step, and subsequent light-boiling point component separation step such as unreacted alcohol is the process of obtaining purified (meth) acrylic acid ester from the top of the column by distillation under reduced pressure to separate high boiling components.
• the (meth) acrylic acid ester in the present invention means methacrylic acid ester such as methyl methacrylate, methyl methacrylate, propyl methacrylate, butyl methacrylate and the like, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate And acrylates such as 2-ethylhexyl acrylate. Of these, butyl acrylate and 2-ethyl acrylate are particularly preferred. Lehexyl.
• the heteroatom-containing chelate complex used in the present invention has an organic ligand forming a heteroatom-containing chelate complex having an acid dissociation constant (pK a) of 4.3 or more.
• pK a acid dissociation constant
• Specific examples of the chelate complex containing a heteroatom atom having an acid dissociation constant of an organic ligand of 4.3 or more that can be used in the present invention include bis (acetylacetonato) manganese (11) and bis ( Acetyl acetonato iron (11), bis (acetyl acetonato) cobalt (11), bis (acetyl acetonato) nickel (11), bis (acetyl acetonato) copper (11), bis (acetyl acetonato) zinc (11) ), Bis (2-aminoethanol) copper (11), bis (2-aminoethanol) nickel (11), bis (2-aminoethanol) zinc (11), bis (2-aminoethanethiol) cobalt (11) ), Bis (2-aminoethanethiol) copper (11), bis (2-aminoethanethiol) zinc (11), bis (imidazole) copper (11), bis (imidazole
• a particularly preferred chelate complex includes a heteroatom-containing chelate complex represented by the following general formula (1).
• M represents a metal atom belonging to Groups 7 to 12 of the Periodic Table of the Group 18 elements, and RR 2 represents the same. It may be one or different, and may be bonded to each other, or a monovalent or divalent aliphatic hydrocarbon group, aromatic hydrocarbon group or heteroatom group.
• Group 8 periodic table (long-periodic table) Specific examples of metal atoms of Groups 7 to 12 include Mn, Fe, Co, Ni, Cu, Zn, and the like. . Of these, Cu is preferred.
• R 1 and R 2 may be the same or different from each other, and may be a monovalent or divalent aliphatic hydrocarbon group, aromatic hydrocarbon group, or heteroatom group which may be bonded to each other.
• the aliphatic hydrocarbon group refers to a saturated or unsaturated, linear, branched or cyclic, optionally substituted monovalent or divalent aliphatic hydrocarbon having 1 to 10 carbon atoms. Represents a group.
• substituent of the aliphatic hydrocarbon group include an aromatic hydrocarbon group such as a fuunyl group and a tolyl group.
• a substituted or unsubstituted linear hydrocarbon group such as a methyl group, a benzyl group, an ethyl group, an n-propyl group, an n-butyl group and an n-hexyl group; i-propyl group, i-propyl group A branched hydrocarbon group such as a monobutyl group; a cyclic hydrocarbon group such as a cyclohexyl group; and a divalent aliphatic hydrocarbon group such as a methylene group, an ethylene group or a propylene group.
• the divalent aliphatic hydrocarbon groups may be bonded to each other to form a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms.
• Specific examples include a tetramethylene group, a pentamethylene group, and a hexamethylene group.
• the aromatic hydrocarbon group represents a monovalent or divalent aromatic hydrocarbon group having 6 to 10 carbon atoms which may be substituted.
• substituent of the aromatic hydrocarbon group include an aliphatic hydrocarbon group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group, and a carbonyl group such as an acetyl group.
• aromatic hydrocarbon group examples include a phenyl group, a naphthyl group, a tolyl group, and a xylyl group.
• the aromatic hydrocarbon groups may be bonded to each other to form a divalent aromatic hydrocarbon group such as a biphenylene group.
• R 1 and R 2 are cross-linked with an oxygen atom, a nitrogen atom, or the like.
• Divalent heteroatom chains are preferred. Specific examples include an ethyleneoxyethylene group.
• heteroatom-containing chelate complex of the present invention include bis (dimethyldithiocarbamic acid) copper (11), bis (getyldithiocarbamic acid) copper (11), and bis (di-n-propyldithio).
• the amount of the heteroatom-containing chelate complex in the present invention varies depending on the concentration of the residual acid catalyst in the (meth) acrylate ester supplied to the rectification step. 5 moles is sufficient. However, if the addition amount is small, the removal of the acid catalyst is insufficient, and if the addition amount is large, the precipitation of the inorganic compound at the bottom of the rectification column occurs, which is not preferable because it causes clogging. Therefore, the preferred range of the addition amount is 0.6 to 3 times mol, particularly 0.9 to 3 times mol.
• the distillation temperature in the present invention can be appropriately selected depending on the corresponding (meth) acrylic acid ester.
• acrylic acid 2 _ In the case of ethylhexyl, it is usually selected from the range of 100 ° C to 140 ° C.
• 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 insufficient, and if it is too long, it has no economic significance.
• the method of adding the heteroatom-containing chelate complex is not particularly limited.
• the (meth) acrylic acid ester which is the bottom liquid after removing the low boiling components, or the distillate after the rectification is refluxed.
• the addition temperature can be appropriately determined.
• the esterification reaction was performed under the following conditions: flask temperature: 95 ° C, reaction time: 14 B. After completion of the esterification reaction, distilled water equivalent to 0.3 in weight ratio was added to the esterification reaction solution, and the remaining catalyst was extracted and removed with distilled water. This operation was repeated three times, and the organic layer was recovered to obtain a crude product of 2-ethylhexyl acrylate.
• a heating test was carried out in the same manner as in Example 1 except that bis (di-n-butyldithiol rubamic acid) copper ( ⁇ ) was added in a molar amount of 0.5 times that of p-toluenesulfonic acid, and heating was completed for 8 hours.
• the concentration of 2-ethylhexanol at that time was 0.090% by weight. This alcohol concentration is within the acceptable range for the product.
• the transesterification between the (meth) acrylic ester and the hydroxy compound which is a side reaction product existing as an impurity is extremely high because the production of alcohol generated by the reaction can be suppressed and a high-purity (meth) acrylate can be obtained.

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

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Citations (3)

• 2002
  • 2002-12-03 WO PCT/JP2002/012681 patent/WO2003048103A1/ja active Application Filing
  • 2002-12-03 AU AU2002349756A patent/AU2002349756A1/en not_active Abandoned
  • 2002-12-03 CN CNB028193024A patent/CN100497290C/zh not_active Expired - Lifetime
  • 2002-12-05 TW TW91135277A patent/TWI247004B/zh not_active IP Right Cessation

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