Preparation method of diethyl succinate

Abstract

The invention discloses a preparation method of butane diacid dimethyl ester. The preparation process comprises the following steps of: (1) the rate of raw materials and a catalyst and dosage quality rate thereof is: butane diacid : industrial ethanol : absolute ethyl alcohol : the catalyst is equal to 1 : 0.8 to 1.1 : 0.1 to 0 : 0.01 to 0.02; 1) putting butane diacid, industrial ethyl alcohol of 20 percent of total amount and the catalyst into an esterification kettle and increasing temperature to 120 DEG C; 2) inputting residual industrial ethanol continuously for 8 hours to 9 hours, maintaining the temperature of the kettle at 115 DEG C to 120 DEG C and the temperature of the top of distillation device less than 105 DEG C; 4) sampling to detect acid value and inputting absolute ethyl alcohol when the acid value is 40mgKOH / g to 48mgKOH / g; 5) sampling to detect acid value after an hour and stopping heating when the acid value is 10mgKOH / g to 15mgKOH / g; 6) reducing the temperature to 80 DEG C after ethyl alcohol is withdrawn from the kettle by opening vacuum; 7) separating the catalyst from the materials cooled to 80 DEG C and putting the catalyst into an alkaline washing kettle; 8) inputting alkali solution of proper amount and mixing for 20 minutes to 40 minutes under temperature of 60 DEG C to 70 DEG C; 9) placing stilly for layering and emitting the lower water layer; 10) adding crude product after the alkaline washing into a rectification kettle, raising the temperature to 150 DEG C to 170 DEG C and dehydrating; 11) opening vacuum and collecting distillate of 160 DEG C to 190 DEG C which is the final product.

Description

technical field [0001] The invention relates to a preparation method of diethyl succinate, in particular to a method for preparing diethyl succinate through catalytic esterification with succinic acid and industrial ethanol. Background technique [0002] Dimethyl nylon acid (a mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate) is a product that has developed rapidly in the past ten years. Due to its excellent performance, it is widely used as an environmental protection high boiling point solvents. Diethyl succinate is widely used in paint, ink, cleaning and other industries due to its environmental protection, strong solvency and high boiling point, and has become a substitute for non-environmental protection products and dimethyl nylon acid. The technical route for producing diethyl succinate is the same as that of dimethyl nylon acid and can be divided into two types: the continuous method under pressure conditions and the batch method under normal p...

AI Technical Summary

Problems solved by technology

Although the continuous method has a large production capacity and is environmentally friendly, its disadvantages are: large investment, high requirements for equipment, harsh reaction conditions, high safety requirements, and difficulty in popularization and application.

Many research institutes of domestic enterprises have been trying to produce this kind of products by the normal pressure batch method, but most of them failed due to the process and equipment, high acid value controlled in the process, low yield, product discoloration and other reasons.

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