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CN-117126051-B - Process for preparing higher fatty alcohol (meth) acrylates

CN117126051BCN 117126051 BCN117126051 BCN 117126051BCN-117126051-B

Abstract

The invention relates to the field of chemical industry and discloses a method for preparing (methyl) acrylic acid higher fatty alcohol ester. The method comprises the steps of enabling higher fatty alcohol to be in contact with excessive (methyl) acrylic acid for esterification reaction, leading water generated in the esterification reaction process out of an esterification reaction system along with the excessive (methyl) acrylic acid, obtaining a (methyl) acrylic acid higher fatty alcohol ester product through post-treatment after the reaction is finished, and extracting and recycling the excessive (methyl) acrylic acid by using hydrophobic fatty alcohol. The method can promote the esterification reaction, improve the conversion rate, does not introduce a third solvent, effectively reduces the discharge of waste liquid, is more environment-friendly, and has the advantages of low process energy consumption and low cost.

Inventors

  • LIU LELE
  • ZHANG YAO
  • SU SHUO
  • WANG NING
  • YU KUN
  • Tian yanan
  • JIN XIN
  • GAO GUOHUA
  • MA DONGQIANG

Assignees

  • 中国石油化工股份有限公司
  • 中国石油化工股份有限公司石油化工科学研究院

Dates

Publication Date
20260505
Application Date
20220519

Claims (10)

  1. 1. A process for preparing a higher fatty alcohol (meth) acrylate, comprising: (1) The method comprises the steps of (1) contacting higher fatty alcohol with excessive (methyl) acrylic acid for esterification reaction, heating a reaction solution to 100 ℃, timing the start of the esterification reaction, controlling the reaction temperature to 100-140 ℃, and continuously distilling and separating water generated in the esterification reaction process by using a water separator along with the excessive (methyl) acrylic acid, wherein the initial molar ratio of the (methyl) acrylic acid to the higher fatty alcohol calculated by hydroxyl is 1.1-3; (2) Extracting and recovering (meth) acrylic acid in the mixture of water and (meth) acrylic acid extracted in the step (1) by using hydrophobic higher fatty alcohol, and recycling the recovered (meth) acrylic acid for esterification reaction in the step (1); (3) Post-treating the material containing the (meth) acrylic acid higher fatty alcohol ester generated by the esterification reaction to obtain the (meth) acrylic acid higher fatty alcohol ester; Wherein the higher fatty alcohol is dodecanol and the hydrophobic higher fatty alcohol is dodecanol.
  2. 2. The method of claim 1, wherein the esterification reaction time is 3-20 hours; And/or, the esterification reaction is carried out in a reactive distillation/rectification apparatus.
  3. 3. The method according to claim 1, wherein in the step (1), the esterification reaction is performed in the presence of a catalyst which is at least one of sulfuric acid, sulfonic acid type, heteropolyacid and acid resin, and the catalyst is used in an amount of 0.05 to 10% by weight based on the total weight of (meth) acrylic acid and higher fatty alcohol.
  4. 4. The method according to claim 1 or 3, wherein in the step (1), the esterification reaction is performed in the presence of a polymerization inhibitor which is at least one of a phenolic polymerization inhibitor, a quinone polymerization inhibitor, an arylamine polymerization inhibitor and an inorganic salt polymerization inhibitor, and the amount of the polymerization inhibitor is 0.03 to 5% by weight based on the total weight of (meth) acrylic acid and higher fatty alcohol.
  5. 5. The method according to claim 4, wherein the volume ratio of the hydrophobic higher fatty alcohol to the mixture used for extraction is 0.3-10:1.
  6. 6. The method according to claim 5, wherein the volume ratio of the hydrophobic higher fatty alcohol to the mixture used for extraction is 1-4:1.
  7. 7. The method of claim 6, wherein the extraction temperature is 0-90 ℃.
  8. 8. The method of claim 7, wherein the extraction temperature is 20-60 ℃.
  9. 9. The process according to claim 1, wherein in the step (3), the post-treatment is performed by sequentially subjecting the material containing the higher fatty alcohol (meth) acrylate to alkali washing, distillation and decolorization.
  10. 10. The method according to claim 1 or 9, wherein in the step (3), the post-treatment is performed by alkali washing with an alkali metal hydroxide solution having a concentration of 1 to 20wt% at a temperature of 20 to 60 ℃, then treating with desalted water to neutrality, then performing reduced pressure distillation at a vacuum of 5 to 95kpa, and then decolorizing with a decolorizing agent.

Description

Process for preparing higher fatty alcohol (meth) acrylates Technical Field The invention relates to the field of chemical industry, in particular to a method for preparing (methyl) acrylic acid higher fatty alcohol ester. Background The (methyl) acrylic acid higher fatty alcohol ester has active double bond, is an important fine chemical product and high polymer monomer, contains hydrophobic long chain aliphatic hydrocarbon skeleton, and its homopolymer or copolymer has the features of water resistance, flexibility, hardness and impact resistance, and is used as oil additive, adsorption resin, adhesive and internal plasticizer, and has wide application in paint, oil additive, plastic, papermaking, leather, cosmetics and other fields. The preparation of fatty alcohol (meth) acrylate usually adopts an ester exchange method, namely, the methyl (meth) acrylate and higher fatty alcohol are subjected to ester exchange reaction in the presence of a catalyst, so that the lower fatty alcohol is continuously removed to promote the reaction, or adopts a direct esterification method of (meth) acrylic acid, namely, the (meth) acrylic acid and higher fatty alcohol are subjected to esterification reaction, so that the byproduct, namely water, is required to be continuously removed to promote the reaction, and compared with the ester exchange method, the reaction temperature of the direct esterification of the (meth) acrylic acid and the higher fatty alcohol is higher, and the reaction efficiency is higher. The esterification reaction equilibrium conversion rate of (methyl) acrylic acid and higher fatty alcohol is low, and the byproduct water is required to be continuously removed, so that the reaction is promoted to be carried out in the forward reaction direction. In general, a low boiling point solvent which can form an azeotrope with water is added into a reaction system, the removal rate of water is improved through azeotropy of the low boiling point solvent and water, CN1733687A discloses a preparation method of higher fatty alcohol ester of ((methyl)) acrylic acid, benzene, toluene, cyclohexane, carbon tetrachloride, chloroform, n-pentane and n-hexane are added into the reaction system as entrainer of water, removal of water is enhanced, the mole ratio of (methyl) acrylic acid and higher fatty alcohol is 0.5-5.0, preferably 1.0-2.0, and the product yield can reach 97.8%. The method has the defects that new substances are added into the reaction mixture, so that on one hand, the rectifying and purifying difficulty of a reaction system is increased, on the other hand, the azeotropic solvent needs to be purified before being recycled to the upstream for recycling, and the solvent azeotropic method can efficiently and rapidly improve the conversion rate of the esterification reaction, but has the advantages of prominent problems of secondary distillation of the solvent, process loss and the like, long overall energy consumption and time and poor color of the product. Disclosure of Invention The invention aims to overcome the problems in the prior art and provide a method for preparing (methyl) acrylic acid higher fatty alcohol ester, which can promote esterification reaction, improve conversion rate, effectively reduce waste liquid discharge, is more environment-friendly and has the advantages of lower process energy consumption and lower cost. The inventor of the invention discovers that the product quality is affected by increasing the amount of higher fatty alcohol to easily cause more alcohol residue in the product, but the reaction can be obviously and effectively promoted to be carried out in the forward reaction direction by increasing the amount of (methyl) acrylic acid, and meanwhile, the excessive (methyl) acrylic acid is easy to remove after the reaction is finished. In order to achieve the above object, the present invention provides a process for producing a higher fatty alcohol (meth) acrylate, comprising: (1) The method comprises the steps of (1) contacting higher fatty alcohol with excessive (methyl) acrylic acid for esterification reaction, wherein water generated in the esterification reaction process is led out of an esterification reaction system along with the excessive (methyl) acrylic acid; (2) Optionally, recovering (meth) acrylic acid from the mixture of water and (meth) acrylic acid extracted in step (1) by extraction with a hydrophobic higher fatty alcohol, and recycling the recovered (meth) acrylic acid for esterification in step (1); (3) Optionally, the material containing the higher fatty alcohol (meth) acrylate produced by the esterification reaction is subjected to post-treatment to obtain the higher fatty alcohol (meth) acrylate. The invention can obtain the following beneficial effects: 1. According to the technical scheme, excessive (methyl) acrylic acid is adopted, and byproduct water is continuously removed through azeotropy, so that the esterification reaction can be effectively pr