Method for preparing alpha ¿C acetyl ¿C gamma - butyrolactone

Abstract

This invention discloses a method for preparing alpha-acetyl-gamma-butyrolactone, which comprises a reaction process and a distillation process. The reaction process comprises: pumping gasified gamma-butyrolactone and ethyl acetate into a reaction loaded with catalyst, and reacting. The method utilizes gamma-butyrolactone and ethyl acetate to react, thus can avoid potential safety hazard caused by using ethylene oxide. The method utilizes supported solid catalyst and fixed bed reactor, and continuous gasification reaction mode to change previous intermittent reaction to continuous reaction, which can realzie uniform distribution of the reactants, prolonged service life of the catalyst, and shortened reaction time, and eliminate the deficiencies of slow heat dissipation and difficult temperature control of reaction kettle. The method has such advantages as stable and safe production, and high product yield and purity. The content of alpha-acetyl-gamma-butyrolactone is greater than or equal to 99.4%, the content of water is less than or equal to 0.15%, and the yield is greater than or equal to 92%.

Description

technical field [0001] The invention relates to a preparation method of intermediates of pharmaceuticals and organic industrial medicines, more specifically to a preparation method of α-acetyl-γ-butyrolactone. Background technique [0002] Various production methods have been proposed for α-acetyl-γ-butyrolactone as raw materials or intermediates of pharmaceuticals in the fields of medicine and organic chemical industry. At present, there are mainly two routes for the preparation of α-acetyl-γ-butyrolactone. One is the process using ethylene oxide as the starting material, and the other is the process using γ-butyrolactone as the starting material. craft. As the raw material of the first process route, ethylene oxide is used, and ethylene oxide is a first-class flammable and explosive chemical product. There are serious safety hazards in the reaction, and it is also difficult to obtain high-purity α -Acetyl-γ-butyrolactone; As the second process route, adopting γ-butyrolac...

AI Technical Summary

Problems solved by technology

As the raw material of the first process route, ethylene oxide is used, and ethylene oxide is a first-class flammable and explosive chemical product. There are serious safety hazards in the reaction, and it is also difficult to obtain high-purity α -Acetyl-γ-butyrolactone; As the second process route, adopting γ-butyrolactone as the process of starting raw material to synthesize α-acetyl-γ-butyrolactone, generally all directly and with γ-butyrolactone Sodium metal is intermittently reacted in the enamel glass reactor. Due to the problems of excessive reaction, slow heat dissipation of the reactor, and difficult temperature control, there are often incidents of charging, burning and explosion in the production process, which have caused many domestic and foreign enterprises to stop using it. The process produces the product

[0003] In addition, in the Chinese patent ZL03128773.5, it is mentioned that toluene is used as a solvent for metal sodium catalysts. In fact, toluene and metal sodium belong to the first-class flammable and explosive chemicals, and there are serious safety hazards in the process of transportation, storage and use. Hidden danger: Although the catalyst metal sodium is stirred in the reactor with toluene as the solvent, and the reactor is made of special stainless steel, there is still friction between the material and the reactor, and the wall thickness of the reactor is thinned, resulting in unsafe factors during use ; Due to the use of toluene in the reaction process as a solvent, phosphoric acid neutralization and other processes, even by distillation at last, can not improve the purity, yield and environmental pollution of α-acetyl-γ-butyrolactone; at last because the invention is still The batch reactor is used, although the structure has been improved, but there are still problems such as slow heat dissipation, difficult temperature control, and long reaction time.