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Method for preparing citraconic anhydride and method for isomerizing/dehydrating itaconic acid

A technology of citraconic anhydride and itaconic acid, applied in chemical instruments and methods, chemical/physical processes, metal/metal oxide/metal hydroxide catalysts, etc. Recycling and other issues

Active Publication Date: 2012-05-23
IND TECH RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its catalyst is easy to combine with itaconic acid or product reaction, so that the yield of citraconic anhydride is lower than 50%.
The catalyst cannot be recycled after the reaction
[0008] WO 1994021589 discloses that organic amides are used as catalysts similar to organic amines to react, the yield is lower than 75%, and the catalyst cannot be recovered

Method used

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  • Method for preparing citraconic anhydride and method for isomerizing/dehydrating itaconic acid
  • Method for preparing citraconic anhydride and method for isomerizing/dehydrating itaconic acid
  • Method for preparing citraconic anhydride and method for isomerizing/dehydrating itaconic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add a stirring magnet, 37.9960 grams of itaconic acid, and 1.0020 grams of heteropolyacid catalyst H in a 100ml double-neck round bottom flask 3 PW 12 o 40 , and 19.0180 grams of N-methyl-2-pyrrolidone (N-methyl-2-Pyrrolidone, hereinafter referred to as NMP). After the round bottom bottle was put into an oil pan at 130°C and heated for about 15 minutes, the solution turned yellow-orange and transparent. After the reaction was heated for 30 minutes, the water vapor generated by the reaction was evaporated under the reduced pressure controlled by a water pump at 150-200 torr. After reacting for 4 hours, samples were taken from the round bottom flask, and the yield of citraconic anhydride was analyzed by gas chromatography to be 80.51%. The above reaction can be represented by the following formula:

[0027]

[0028] Please refer to Table 1 for the ratio of reactants and reaction conditions.

Embodiment 2

[0030] Add a stirring magnet, 37.9860 grams of itaconic acid, and 1.0110 grams of heteropolyacid catalyst H in a 100ml double-neck round bottom flask 4 SiMo 12 o 40 , and 18.9960 grams of N-methyl-2 pyrrolidone (N-methyl-2-Pyrrolidone, hereinafter referred to as NMP). After the round bottom bottle was put into an oil pan at 130°C and heated for about 15 minutes, the solution turned yellow-orange and transparent. After the reaction was heated for 30 minutes, the water vapor generated by the reaction was evaporated under the reduced pressure controlled by a water pump at 150-200 torr. After reacting for 4 hours, samples were taken from the round bottom flask, and the yield of citraconic anhydride was analyzed by gas chromatography to be 81.24%. Please refer to Table 1 for the ratio of reactants and reaction conditions.

Embodiment 3

[0032] Add a stirring magnet, 38.0030 grams of itaconic acid, 1.0040 grams of heteropolyacid catalyst H in a 100ml double-neck round bottom flask 4 SiW 12 o 40 , and 19.0080 grams of N, N-dimethylacetamide (N, N-di-methylacetamide, hereinafter referred to as DMAC). After the round bottom bottle was put into an oil pan at 130°C and heated for about 15 minutes, the solution turned yellow-orange and transparent. After the reaction was heated for 30 minutes, the water vapor generated by the reaction was evaporated under the reduced pressure controlled by a water pump at 150-200 torr. After reacting for 4 hours, samples were taken from the round bottom flask, and the yield of citraconic anhydride was analyzed by gas chromatography to be 71.35%. Please refer to Table 1 for the ratio of reactants and reaction conditions.

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Abstract

The invention provides a method for preparing citraconic anhydride and a method for isomerizing / dehydrating itaconic acid. The method for preparing the citraconic anhydride comprises the following steps of: supplying the itaconic acid to serve as a reaction initiator; in the presence of a catalytic agent, and carrying out isomerizing / dehydrating reaction on the itaconic acid or a combination containing the itaconic acid to obtain the citraconic anhydride, wherein the catalytic agent contains heteropoly acid or salt of the heteropoly acid. The method for isomerizing / dehydrating itaconic acid comprises the following steps of: supplying the itaconic acid to serve as the reaction initiator; supplying the heteropoly acid or the salt of the heteropoly acid to form a mixture with the itaconic acid; and heating the mixture so as to carry out isomerizing / dehydrating reaction on the mixture, thereby obtaining the citraconic anhydride. According to the method, the itaconic acid can be converted into the citraconic anhydride product with high yield and application value under the preparation condition of the use or non-use of a dissolvant, and the industrial volume production is easily realized.

Description

technical field [0001] The invention relates to a method for preparing citraconic anhydride, more particularly, to a method for preparing citraconic anhydride from itaconic acid. Background technique [0002] Citraconic anhydride (citraconic anhydride) is a compound similar to maleic anhydride molecules, also known as 2-methyl-maleic anhydride, that is, the second carbon atom of maleic anhydride has an extra 1 methyl functional group. Because its molecule is similar to maleic anhydride, it can also be made into downstream application derivatives similar to maleic anhydride. For example, citraconic anhydride can be used as an additive for unsaturated resin (unsaturated polyester resin, UPR), polyimide derivatives synthesized by citraconic anhydride can be used as composite materials or rubber additives, or citraconic anhydride can be used to synthesize bis Alcohol derivatives can be used as monomers of polyesters. [0003] The early synthesis method of citraconic anhydride...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/60B01J27/188B01J23/28B01J23/30
Inventor 许希彦赵玉山
Owner IND TECH RES INST
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