A kind of preparation method of citraconic anhydride

A technology of citraconic anhydride and itaconic acid, applied in the direction of organic chemistry, can solve the problems of harsh reaction conditions, high reaction temperature, and many by-products, and achieve the effects of convenient solvent recovery, simple post-treatment, and no impact on yield

Active Publication Date: 2017-02-22
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The pyrolysis process is relatively mature, but there are disadvantages such as low yield, high cost, and large equipment investment.
The thermal dehydration method has disadvantages such as harsh reaction conditions, low yield, and high reaction temperature.
The chemical reagent dehydration method has defects such as many by-products, high product cost, and large discharge of three wastes.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1: 0.10g of strontium sulfate, 10.0g of itaconic acid and 10.0g of tetrahydronaphthalene were added to a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after water separation at 210°C for 4 hours, and the resulting product was decompressed Distillation, under a vacuum of 300Pa, distill the solvent at 85°C to recover the solvent, and collect the product at 100°C to obtain a colorless liquid product, citraconic anhydride, with a yield of 99.0% and a purity of 99.6%.

Embodiment 2

[0019] Embodiment 2: 0.10g magnesium sulfate, 50.0g itaconic acid and 500.0g o-dichlorobenzene are added in the reactor that is equipped with oil-water separator, thermometer and stirring, stop reaction after 10h of water separation reaction at 155 ℃, the gained product is reduced Pressure distillation, under vacuum degree of 300Pa, distill and recover the solvent at 85°C, and collect the product at 100°C to obtain a colorless liquid product, citraconic anhydride, with a yield of 98.2% and a purity of 99.3%.

Embodiment 3

[0020] Example 3: 1.0g of barium sulfate, 50.0g of itaconic acid and 10.0g of xylene were added to a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after 1.0h of water separation at 130°C, and the resulting product was decompressed Distillation, under a vacuum of 300Pa, distill the solvent at 85°C to recover the solvent, and collect the product at 100°C to obtain a colorless liquid product, citraconic anhydride, with a yield of 97.5% and a purity of 99.5%.

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Abstract

A preparation method for citraconic anhydride by using alkaline earth metal oxide or alkali earth metal sulphate to catalyze itaconate is characterized in that alkali earth metal oxide or alkali earth metal sulphate is used as a catalyst, the mass ratio of itaconate to the catalyst is 50: 1 to 200: 1, and the mass ratio of itaconate to a solvent is 1: 1 to 1:10, reaction is carried out for 1.0-10.0 h to prepare citraconic anhydride at the reaction temperature of 130-210 DEG C, and the solvent is recycled and reused. Compared with the prior art, the preparation method has the advantages that 1, the source of the catalyst is wide, the cost is low, and the reaction speed is high; 2, the post-treatment of the product is simple, and the obtained citraconic anhydride is good in purity and high in yield; 3, the solvent is convenient to recycle and can be reused, and the recycled solvent has no influence on the productivity.

Description

technical field [0001] The invention relates to a method for preparing citraconic anhydride, in particular to a novel method for preparing citraconic anhydride by catalyzing itaconic acid with an alkaline earth metal oxide or an alkaline earth metal sulfate. Background technique [0002] Citraconic anhydride (2-methylbutene dianhydride) is an important intermediate in the synthesis of chemical products such as pharmaceuticals, pesticides, surfactants and resins. At present, the methods for producing citraconic anhydride mainly include cracking method, thermal dehydration method, chemical reagent dehydration method and azeotropic dehydration method. The pyrolysis process is relatively mature, but there are disadvantages such as low yield, high cost, and large investment in equipment. The thermal dehydration method has disadvantages such as harsh reaction conditions, low yield, and high reaction temperature. The chemical reagent dehydration method has defects such as many by...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D307/60
CPCC07D307/60
Inventor 刘仕伟李露于世涛解从霞刘福胜宋怡鹏
Owner QINGDAO UNIV OF SCI & TECH
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