Synthetic method for alpha-acetyl-gamma-butyrolactone

A synthesis method and a technology for butyrolactone, applied in the direction of organic chemistry and the like, can solve the problems of fire, large potential safety hazard, violent reaction, etc., and achieve the effect of reducing potential safety hazard and reducing production cost.

Inactive Publication Date: 2013-11-13
江苏兄弟维生素有限公司
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Problems solved by technology

This is the current mainstream industrial synthesis method. However, due to the strong activity of sodium, a large amount of hydrogen gas is generated during the production process, the reaction is violent, and the safety hazard is great. The manufacturer frequently occurs large and small fires, although the cost is lower than the epoxy method. , but it is greatly affected by the market price of γ-butyrolactone and metal sodium

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  • Synthetic method for alpha-acetyl-gamma-butyrolactone

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Embodiment 1

[0018] (1) Preparation of chloroethanol acetoacetate:

[0019] Add 100g of diketene, 105g of 2-chloroethanol, and 20g of sodium ethoxide into a 500ml round-bottomed reaction flask, start stirring, heat to 75°C for reflux reaction for 8 hours, then cool down to room temperature, and the reaction is completed to obtain a mixed solution of 187.09g of chloroethanol acetoacetate (Diketene conversion rate 95%).

[0020] (2) Preparation of α-acetyl-γ-butyrolactone:

[0021] Add 80ml of toluene to the flask containing the mixed solution of chloroethanol acetoacetate, stir and mix and add 175g of 32% liquid caustic soda dropwise at a controlled temperature of 15~30°C, strictly control the reaction temperature (15~30°C), and keep warm for the reaction after the dropwise addition 2h, then use hydrochloric acid to neutralize to PH7.5, continue to stir for 1h, stand to separate layers for 1h, vacuum concentrate the upper layer to a liquid temperature of 120°C, then cool down and release t...

Embodiment 2

[0023] (1) Preparation of bromoethanol acetoacetate:

[0024] Add 100g of diketene, 160g of 2-bromoethanol, and 20g of sodium ethylate into a 500ml round-bottomed reaction flask, start stirring, heat to 75°C for reflux reaction for 8 hours, then cool down to room temperature, and the reaction ends to obtain 236.27g of bromoethanol acetoacetate mixed solution ( The conversion rate of diketene is 95%).

[0025] (2) Preparation of α-acetyl-γ-butyrolactone:

[0026] Add 80ml of toluene to the flask containing the mixed solution of chlorobromoethanol acetoacetate, stir and mix and add 32% liquid caustic soda (175g) dropwise at a controlled temperature of 15~30°C, strictly control the reaction temperature, keep the reaction for 2 hours after the dropwise addition, and then Neutralize to PH7.5 with hydrochloric acid, continue to stir for 1h, let the layers stand for 1h, concentrate the upper layer under reduced pressure to 120°C, then cool down and release the concentrated solution,...

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Abstract

The invention relates to the technical field of chemical product preparation, and particularly relates to a synthetic method for alpha-acetyl-gamma-butyrolactone. The synthetic method comprises the steps of carrying out an aldol reaction on ketene dimer and 2-chloroethanol under the effect of a catalyst sodium alkoxide to obtain acetyl chloride ethanol acetate; preparing alpha-acetyl-gamma-butyrolactone: adding a solvent to acetyl chloride ethanol acetate, mixing with stirring, carrying out an intramolecular Claisen-Schmidt condensation reaction under the effect of an alkali catalyst, and directly generating alpha-acetyl-gamma-butyrolactone by cyclization. The synthetic method for alpha-acetyl-gamma-butyrolactone can prevent use of dangerous chemical products such as ethylene oxide, metallic sodium and the like and greatly reduce security risks. Besides, the synthetic yield is obviously higher than that of a conventional process, and production cost is significantly reduced.

Description

technical field [0001] The invention relates to the technical field of preparation of chemical products, in particular to a synthesis method of α-acetyl-γ-butyrolactone. Background technique [0002] There are two main methods for industrially synthesizing α-acetyl-γ-butyrolactone (ABL): 1. Epoxy method: Ethyl acetoacetate and ethylene oxide are catalyzed and condensed by liquid alkali in an aqueous phase system. Synthesize sodium butyrolactone, then neutralize with hydrochloric acid, extract with benzene several times, discharge the lower water layer, and concentrate the upper oil layer to obtain the crude product of α-acetyl-γ-butyrolactone, α-acetyl-γ-butyrolactone The crude product is purified by high vacuum to obtain the finished product α-acetyl-γ-butyrolactone, and the best yield is only 60%. This is the synthetic method commonly used during the 1990s. Due to the low flash point of ethylene oxide, high vapor pressure, difficult transportation, large amount of benzen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/33
Inventor 李健平李来成陈英明
Owner 江苏兄弟维生素有限公司
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