Method for preparing alpha-acetyl-gamma-butyrolactone by using recycled reaction material

Abstract

The invention relates to a method for preparing alpha-acetyl-gamma-butyrolactone by using a recycled reaction material, and particularly relates to a method for preparing high-yield alpha-acetyl-gamma-butyrolactone by reaction between recyclable cheap acylating agent and a catalyst in an inert solvent. The method comprises the six steps of acylation reaction, separation of reaction materials, neutral reaction, desolvation and distillation treatment, recovery treatment and cyclic utilization of a waste solvent. Full recycling of the materials is successfully achieved; the problem that a lot of methylbenzene-ethyl ester-ethanol ternary azeotropic solvent is generated in the traditional main technology at home is avoided; all materials can be recycled except for small loss in the reaction process; the environmental pollution is greatly reduced; and the preparation method accords with the national industrial policy at present, and is suitable for industrial popularization.

Description

technical field [0001] The invention relates to a preparation method of α-acetyl-γ-butyrolactone, which can be recycled and used mechanically as a reaction material, in particular to a method for preparing high-yield Method for rate α-acetyl-γ-butyrolactone. Background technique [0002] α-acetyl-γ-butyrolactone is an important chemical intermediate, which can be used to prepare a variety of drugs. Its synthesis process route can be mainly divided into two types, the process route using ethylene oxide and ethyl acetoacetate as starting materials and the process route using γ-butyrolactone and acetate as starting materials. Since ethylene oxide is a Class I flammable and explosive chemical, there are serious safety hazards in the storage, transportation and production links, so domestic production companies do not use this process route, but usually use γ-butylene oxide Lactone, acetate is the technical route of starting material. [0003] Several known in the prior art ta...

AI Technical Summary

Problems solved by technology

Sodium metal is used as a catalyst to catalyze the reaction of acetate and gamma-butyrolactone at 100-105°C in the presence of toluene solvent, as reported in Chinese patent CN1548427, because the yield is good and the cost is low, although there are major safety hazards (explosion or fire accident caused by improper handling of sodium metal), but it is still the main process route adopted by domestic manufacturers

Although new Chinese patent reports try to reduce the potential safety hazards of this process by adding sodium metal and controlling the reaction process (for example, Chinese patent CN 101768141A reports adding sodium metal in batches and CN20101053442. specific surface area of ​​sodium metal), but because this process route must use sodium metal, in essence, there is no problem that can fundamentally solve potential safety hazards

Chinese patent CN 101092407B reports that α-acetyl-γ-butyrolactone is synthesized by acylating ethyl acetate and γ-butyrolactone in the gas phase with a fluorine alkali solid-phase catalyst. It leads to high cost and product quality problems. At present, no production enterprise adopts it.

For example, Japanese Patent 45 / 009538 reports the acylation reaction of butyl acetate and γ-butyrolactone catalyzed by sodium butoxide, and Japanese Patent 58 / 099473 reports the acylation reaction of ethyl acetate and γ-butyrolactone catalyzed by sodium methoxide. However, due to the use of high-boiling point solvents, the high-boiling point solvents are difficult to remove, resulting in low product yields, and the patent does not pay attention to the recovery of reaction materials, so the method has not been industrially adopted on a large scale use

U.S. Patent No. 5,789,603 improves this process route, adopts continuous reaction and high-pressure reaction, and uses sodium alkoxide of carbon 1-4 to catalyze the acetate and gamma of alcohol of carbon 1-4 in the absence of other solvents. -Acylation reaction of butyrolactone, in the case of using the sodium alkoxide method for the first time, the yield is increased to about 90% and the product purity reaches 99%, making the sodium alkoxide method really reach or exceed metal sodium in the industrial sense However, due to the low boiling point of the alcohol and ester of the raw materials, subsequent high-pressure reaction is required to complete the reaction, and the continuous reactor and high-pressure reactor used are due to high equipment requirements, large investment costs, and strict operating technical requirements. It is not easy to be widely used in industry, and the patent also does not pay attention to the recycling of reaction materials

[0006] In summary, although the existing method discloses the preparation of α-acetyl-γ-butyrolactone with sodium methoxide as a catalyst, there are problems of low yield and difficult removal of the used high boiling point solvent or harsh reaction conditions and high equipment requirements problems, and no attention to the recycling of reaction materials, not suitable for industrial use

Images