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CN-122006818-A - Absent phosphotungstic acid quaternary ammonium salt catalyst and preparation method and application thereof

CN122006818ACN 122006818 ACN122006818 ACN 122006818ACN-122006818-A

Abstract

A preparation method and application of a catalyst of a quaternary ammonium salt of a short-site phosphotungstic acid belong to the field of azelaic acid catalytic synthesis. The invention prepares the absent phosphotungstic acid sodium salt by reacting phosphotungstic acid hydrate in sodium bicarbonate-adjusted pH 4.0-5.0 water solution for 3-6 hours at 40-60 ℃, and then makes the absent phosphotungstic acid sodium salt and quaternary ammonium salt undergo ion exchange reaction at 60-80 ℃ to obtain the absent phosphotungstic acid quaternary ammonium salt catalyst. The catalyst is used for catalyzing the oxidation reaction of oleic acid and hydrogen peroxide, and the azelaic acid is prepared efficiently by reacting for 6-12 hours at 70-110 ℃. The catalyst has the advantages of lack of active sites and quaternary ammonium salt modification, high catalytic activity and high selectivity on double bond oxidation of oleic acid, good stability, and easy recovery and repeated use through solid-liquid separation. The whole reaction system has mild conditions, does not need a strong corrosive oxidant or high-pressure equipment, and is safe in process and environment-friendly.

Inventors

  • SHANG QIANQIAN
  • ZHANG MENG
  • ZHOU YONGHONG
  • LIU DAN
  • HU LIHONG
  • JI YANBO
  • TIAN LINFENG

Assignees

  • 中国林业科学研究院林产化学工业研究所

Dates

Publication Date
20260512
Application Date
20260401

Claims (10)

  1. 1. A preparation method of the absent phosphotungstic acid quaternary ammonium salt catalyst is characterized by comprising the following steps of (1) dissolving a phosphotungstic acid hydrate in water, adding sodium bicarbonate to adjust the pH value of a system to 4.0-5.0, reacting for 3-6 hours at 40-60 ℃ to obtain an absent phosphotungstic acid sodium salt aqueous solution, (2) dissolving quaternary ammonium salt in water to obtain a quaternary ammonium salt aqueous solution, dripping the quaternary ammonium salt aqueous solution into the absent phosphotungstic acid sodium salt aqueous solution obtained in the step (1), reacting for 0.5-2 hours at 60-80 ℃, standing, filtering and separating the mixture to obtain a solid after the reaction is finished, and drying to obtain the absent phosphotungstic acid quaternary ammonium salt catalyst.
  2. 2. The method according to claim 1, wherein in the step (2), the quaternary ammonium salt is trioctylmethyl ammonium chloride, trioctylmethyl ammonium bromide or tetraoctyl ammonium chloride.
  3. 3. The method according to claim 1, wherein in the step (2), the molar ratio of the absent phosphotungstic acid sodium salt to the quaternary ammonium salt is (0.5 to 1.5): 1.
  4. 4. A short-site quaternary ammonium phosphotungstate catalyst prepared by the preparation method of any one of claims 1 to 3.
  5. 5. The use of the absent quaternary ammonium phosphotungstate catalyst as claimed in claim 4 for preparing azelaic acid by catalyzing oleic acid oxidation.
  6. 6. A method for preparing azelaic acid by oxidizing oleic acid is characterized by comprising the steps of mixing oleic acid, a catalyst and hydrogen peroxide, and carrying out oxidation reaction under a heating condition to obtain azelaic acid, wherein the catalyst is the absent phosphotungstic acid quaternary ammonium salt catalyst according to claim 4.
  7. 7. The method of claim 6, wherein the mass ratio of the oleic acid to the hydrogen peroxide to the catalyst is 1 (1-8): 0.03-0.20, wherein the hydrogen peroxide is calculated as pure substances.
  8. 8. The method of claim 6, wherein the temperature of the oxidation reaction is 70 ℃ to 110 ℃.
  9. 9. The method of claim 6, wherein the time of the oxidation reaction is 6 to 12 hours.
  10. 10. The method according to claim 6, wherein after the completion of the reaction, the catalyst is separated by centrifugation, and the separated catalyst can be reused after drying.

Description

Absent phosphotungstic acid quaternary ammonium salt catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of catalyst preparation and organic synthesis, and particularly relates to a catalyst of a quaternary ammonium phosphotungstate in a absent position, a preparation method thereof and application of the catalyst in preparing azelaic acid by catalyzing oleic acid oxidation. Technical Field Azelaic acid, which is a medium-chain organic dibasic acid, is a key intermediate for synthesizing high-performance nylon, high-grade lubricant, plasticizer and other fine chemicals, and has important industrial application value. Currently, azelaic acid is produced industrially mainly by oxidative cleavage of oleic acid. The oxidation method adopted in the prior art mainly comprises an ozone oxidation method, a potassium permanganate oxidation method and a hydrogen peroxide oxidation method. The ozone oxidation method has the problems of high ozone toxicity, high energy consumption, special requirements on reaction equipment and the like. The oxidation method of potassium permanganate has the defects of poor selectivity and easiness in generating a large amount of manganese-containing waste to cause environmental pollution. In contrast, hydrogen peroxide is an ideal oxidant friendly to the environment because of its strong oxidizing power, the reaction by-product is only water, and the safety is high. In oleic acid oxidation systems using hydrogen peroxide as the oxidant, phosphotungstic acid is often used as a catalyst. However, the phosphotungstic acid has a phase separation problem with the organic raw material oleic acid in a homogeneous reaction system, so that the mass transfer efficiency is low, and the reaction rate is limited. To solve this problem, researchers have introduced a phase transfer catalyst to form a quaternary ammonium phosphotungstate catalytic system. The system improves mass transfer to a certain extent and is convenient for separating and recovering the catalyst. However, the prior art still has obvious defects that firstly, under the condition of violent oxidation reaction, the phosphotungstic acid anion skeleton in the phosphotungstic acid quaternary ammonium salt can be decomposed, so that active components are lost, the stability of the catalyst is poor, and secondly, partial decomposition products of the catalyst can be mixed in the products, thereby increasing the difficulty of subsequent azelaic acid separation and purification. Therefore, developing a novel catalyst which has high catalytic activity and high structural stability and is easy to separate and recycle in a hydrogen peroxide oxidation system is a technical problem to be solved in the field. Disclosure of Invention The invention provides a deficiency phosphotungstic acid quaternary ammonium salt catalyst and a preparation method and application thereof based on the defects of the existing phosphotungstic acid quaternary ammonium salt catalyst in a hydrogen peroxide oxidation system, which are pointed out in the background art, so as to solve the problems of insufficient structural stability and easy loss of living components in the process of preparing azelaic acid by oxidizing oleic acid by the existing catalyst, simultaneously realize easy separation and repeated use of the catalyst on the premise of keeping high catalytic activity and mass transfer efficiency, and finally simplify the process by improving a catalytic system, and avoid using strong corrosive or high-risk reagents, thereby improving the safety and environmental friendliness of the whole production process. The preparation method of the absent quaternary ammonium phosphotungstate catalyst comprises the following steps of (1) dissolving a phosphotungstic acid hydrate in water, adding sodium bicarbonate to adjust the pH value of a system to 4.0-5.0, reacting for 3-6 hours at 40-60 ℃ to obtain an absent quaternary ammonium phosphotungstate sodium salt aqueous solution, (2) dissolving quaternary ammonium salt in water to obtain a quaternary ammonium salt aqueous solution, dripping the quaternary ammonium salt aqueous solution into the absent quaternary ammonium phosphotungstate sodium salt aqueous solution obtained in the step (1), reacting for 0.5-2 hours at 60-80 ℃, and (3) standing, filtering and separating the mixture to obtain a solid after the reaction is finished, and drying to obtain the absent quaternary ammonium phosphotungstate catalyst. In the step (2), the quaternary ammonium salt is trioctyl methyl ammonium chloride, trioctyl methyl ammonium bromide or tetraoctyl ammonium chloride. In the step (2), the molar ratio of the absent phosphotungstic acid sodium salt to the quaternary ammonium salt is (0.5-1.5): 1. The preparation method of the catalyst is characterized in that the catalyst is prepared from the short-site phosphotungstic acid quaternary ammonium salt. The application of the a