CN105037301A - Preparation method for citraconic anhydride - Google Patents

Abstract

A method for preparing citraconic anhydride from itaconic acid catalyzed by alkaline earth metal oxides or alkaline earth metal sulfates is characterized in that alkaline earth metal oxides or alkaline earth metal sulfates are used as catalysts, and the mass ratio of itaconic acid and catalyst is 50:1 ～200:1, the mass ratio of itaconic acid to solvent is 1:1～1:10, and the reaction temperature is 130～210°C for 1.0～10.0h to prepare citraconic anhydride, and the solvent is recovered and reused. Compared with the prior art: 1. The catalyst has wide source, low price and fast reaction speed. 2. The post-treatment of the product is simple, and the obtained citraconic anhydride has good purity and high yield. 3. The solvent used is easy to recover and can be reused without affecting the yield.

Description

A kind of preparation method of citraconic anhydride

technical field

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

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-products, high product cost, and large discharge of three wastes. Compared with the above-mentioned method, the azeotropic dehydration method is that in the presence of an azeotropic solvent with water, itaconic acid can be catalyzed to obtain the product citraconic anhydride. This method has the advantages of mild reaction conditions, less side reactions, and high product quality. The shortcoming that exists in above-mentioned method. Therefore, the present application uses cheap and readily available alkaline earth metal oxides or alkaline earth metal sulfates as catalysts to catalyze the preparation of citraconic anhydride from itaconic acid.

Contents of the invention

The purpose of the present invention is to provide a catalyst with excellent catalytic performance to catalyze itaconic acid to prepare citraconic anhydride.

The invention relates to a method for preparing citraconic anhydride from itaconic acid catalyzed by alkaline earth metal oxide or alkaline earth metal sulfate, which is characterized in that alkaline earth metal oxide or alkaline earth metal sulfate is used as the catalyst, and the mass ratio of itaconic acid to the catalyst is 50:1～500:1, the mass ratio of itaconic acid to solvent is 1:1～1:10, and the reaction temperature is 130～210°C for 1.0～10.0h to prepare citraconic anhydride, and recover and reuse the solvent; the alkaline earth Metal oxide or alkaline earth metal sulfate catalyst is a kind of in magnesium oxide, calcium oxide, barium oxide, strontium oxide, magnesium sulfate, calcium sulfate, barium sulfate and strontium sulfate; Described solvent is xylene, o-dichlorobenzene and One of tetrahydronaphthalene.

The present invention is characterized in that the reaction conditions are that the mass ratio of itaconic acid to catalyst is 50:1～100:1, the mass ratio of itaconic acid to solvent is 1:1～1:5, and the reaction temperature is 150～100℃. 210 ℃, reaction time 4.0 ~ 8.0h is better.

The present invention solves this technical problem through the following technical solutions:

The specific technical scheme is illustrated by taking strontium sulfate catalyst as an example.

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 distilled under reduced pressure. Under the temperature of 300Pa, the solvent tetrahydronaphthalene was recovered by distillation at 85°C, and the product was collected at 100°C to obtain the colorless liquid citraconic anhydride with a yield of 99.0% and a purity of 99.6%.

Compared with traditional reaction, the present invention is characterized in that:

1. Catalyst has wide sources, low price and fast reaction speed.

2. The post-treatment of the product is simple, and the obtained citraconic anhydride has good purity and high yield.

3. The solvent used is easy to recover and can be reused without affecting the yield.

Specific implementation method

The method of the present invention will be further described below in conjunction with the examples, which are not intended to limit the present invention.

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%.

Comparative Example 1: 0.10 g of sulfuric acid and 10.0 g of itaconic acid were added into a reactor equipped with a water separator, a thermometer and agitation, and the reaction was stopped after water separation at 210° C. for 4 hours. Under 100°C, the product was collected to obtain a dark yellow product, citraconic anhydride, with a yield of 79.2% and a purity of 96.5%.

Comparative Example 2: 0.10 g of sulfuric acid, 10.0 g of itaconic acid and 10.0 g of tetrahydronaphthalene were added to a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after 4 hours of water separation at 210 ° 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 dark yellow product, citraconic anhydride, with a yield of 36.2% and a purity of 75.6%.

Comparative Example 3: 0.10 g of disodium hydrogen phosphate, 10.0 g of itaconic acid and 10.0 g of tetrahydronaphthalene were added into a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after 4 hours of water separation at 210° C., and the resulting The product was distilled under reduced pressure, and the solvent was recovered by distillation at 85°C under a vacuum of 300Pa, and the product was collected at 100°C to obtain a colorless liquid product, citraconic anhydride, with a yield of 93.1% and a purity of 95.4%.

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%.

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%.

Example 4: 0.1g of calcium sulfate, 20.0g of itaconic acid and 20.0g of o-dichlorobenzene were added to a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after 5.0 hours of water separation at 150°C, and the resulting product was Distill under reduced pressure, under vacuum degree of 300Pa, distill and recover the solvent at 85°C, and collect the product at 100°C to obtain the colorless liquid citraconic anhydride with a yield of 99.2% and a purity of 99.6%.

Example 5: 0.1g of magnesium oxide, 20.0g of itaconic acid and 20.0g of o-dichlorobenzene were added to a reactor equipped with an oil-water separator, a thermometer and agitation, and the reaction was stopped after 7.0 hours of water separation at 150°C, and the resulting product was Distillation under reduced pressure, 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 99.5% and a purity of 99.7%.

Example 6: 0.1g of barium oxide, 20.0g 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 5.0 hours of water separation at 135°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 99.3% and a purity of 99.5%.

Example 7: 0.1g of calcium oxide, 30.0g of itaconic acid and 60.0g 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 98.8% and a purity of 99.6%.

Example 8: 0.1g of strontium oxide, 10.0g 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 4.0 hours 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 99.2% and a purity of 99.7%.

Embodiment 9: Collect the solvent tetrahydronaphthalene, o-dichlorobenzene, dimethylbenzene or cumene distilled out in the above-mentioned embodiment respectively, in 0.1g barium sulfate, 30.0g itaconic acid and 60.0g solvent, reflux reaction fraction The experiment was stopped after 6.0 h of water, and the resulting product was distilled under reduced pressure. Under a vacuum of 300 Pa, the solvent was recovered by distillation at 85 ° C, and the product was collected at 100 ° C. The results showed that tetralin, o-dichlorobenzene, xylene and iso In the process of repeated use of propylbenzene for 5 times, the yield of citraconic anhydride is greater than 99% each time, and the purity is greater than 99.2%.

Claims (2)

1. an alkaline earth metal oxide or alkaline earth metal sulphate catalysis methylene-succinic acid prepare the method for citraconic anhydride, it is characterized in that adopting alkaline earth metal oxide or alkaline earth metal sulphate to be catalyzer, prepare citraconic anhydride than for 50:1 ~ 500:1, methylene-succinic acid and solvent quality than reaction 1.0 ~ 10.0h at for 1:1 ~ 1:10, temperature of reaction 130 ~ 210 DEG C at methylene-succinic acid and catalyst quality, and reclaim and reuse solvent; Described alkaline earth metal oxide or sulfate catalyst are the one in magnesium oxide, calcium oxide, barium oxide, strontium oxide, magnesium sulfate, calcium sulfate, barium sulfate and Strontium Sulphate; Described solvent is the one in dimethylbenzene, orthodichlorobenzene and naphthane.

2. preparation method as claimed in claim 1, it is characterized in that described reaction conditions with the mass ratio of methylene-succinic acid and catalyzer be 50:1 ~ 100:1, methylene-succinic acid and solvent quality be than being good for 1:1 ~ 1:5, temperature of reaction 150 ~ 210 DEG C, reaction times 4.0 ~ 8.0h.