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Environment-friendly 2-ethyl-4-methylimidazole synthesis method

A synthetic method, the technology of methylimidazole, applied in the field of organic synthesis, can solve the problems of high toxicity, difficult production, high price, etc.

Active Publication Date: 2020-02-28
广东固研电子材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In summary, the existing preparation methods of 2-ethyl-4-methylimidazole have production difficulties such as high toxicity, high pollution, and dangerous operation, which are also the reasons for the high price of 2-ethyl-4-methylimidazole

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Put 88g of methyl propionate and 222g of 1,2-propanediamine into the flask, reflux at 80°C for 3 hours, add 3g of dibutyltin oxide and 176g of trimethylbenzene, and distill out the unreacted substances with low boiling point at low temperature , and then heated to 180 ° C reflux with water for 3 hours until no water distilled off. Distill under reduced pressure, collect fractions at 102-112°C / 2.0kpa, and obtain 98g of 2-ethyl-4-methylimidazoline with a yield of 87.5%.

Embodiment 2

[0017] Put 88g of methyl propionate and 296g of 1,2-propylenediamine in a flask, reflux at 80°C for 3 hours, evaporate unreacted substances, then add 5g of 5A molecular sieve and 176g of toluene to carry out reflux with water reaction until anhydrous part distilled off. Finally, distilled under reduced pressure and collected fractions at 102-112°C / 2.0kpa to obtain 92g of 2-ethyl-4-methylimidazoline with a yield of 82%.

Embodiment 3

[0019] Put 88g of methyl propionate and 148g of 1,2-propanediamine into the flask, reflux at 80°C for 3 hours, add 3g of activated alumina and 176g of xylene, first distill out unreacted substances at low temperature, and then raise the temperature to reflux Dehydration reaction, until no water is distilled off. Distill under reduced pressure, collect fractions at 102-112°C / 2.0kpa, and obtain 101 g of 2-ethyl-4-methylimidazoline with a yield of 90%.

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PUM

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Abstract

The invention discloses an environment-friendly synthesis method of 2-ethyl-4-methylimidazole, and belongs to the technical field of organic synthesis. The method comprises: generating aminopropyl propionamide at a temperature of 80 DEG C from low-toxicity methyl propionate and 1,2-diaminopropane according to a proper reaction ratio; carrying out cyclization with water on the aminopropyl propionamide and an aromatic hydrocarbon in the presence of a catalyst to generate 2-ethyl-4-methylimidazoline; and dehydrogenating the 2-ethyl-4-methylimidazoline at a temperature of 120-40 DEG C in the presence of a pd / c catalyst to prepare the 2-ethyl-4-methylimidazole. According to the invention, the 2-ethyl-4-methylimidazole is prepared by using the method, so that the use of high-toxicity propionitrile, high-pollution aldehyde and ammonia and high-risk Raney nickel catalysts capable of burning in the presence of air are avoided, no waste ammonia is generated in the production process, and the method belongs to an environment-friendly method for preparing the 2-ethyl-4-methylimidazole.

Description

technical field [0001] The invention relates to an environment-friendly preparation method of 2-ethyl-4-methylimidazole, which belongs to the technical field of organic synthesis. Background technique [0002] 2-Ethyl-4-methylimidazole is an excellent curing agent for epoxy resin. It is liquid at room temperature, less dosage, easy to mix with epoxy resin, the mixture has a long pot life, and the curing temperature is not high; the cured product has excellent heat resistance, adhesion and insulation, and is widely used in adhesives, coatings, Composite materials and other fields. There are three main methods for producing 2-ethyl-4-methylimidazole: one is the aldehyde-ammonia method, that is, using n-propionaldehyde, methylglyoxal aqueous solution and ammonia water as raw materials, and preparing 2-ethyl-4-methylimidazole in one pot For imidazole, the yield of this method is very low, the purification is complicated, and a large amount of aldehyde and ammonia wastewater is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D233/58
CPCC07D233/58
Inventor 康富春唐增花刘海明
Owner 广东固研电子材料有限公司