A kind of method for preparing alkylpyrrolidone by amination of 1,4-butanediol

Abstract

The invention discloses a method for preparing alkylpyrrolidone by amination of 1,4-butanediol, comprising the following steps: (1) preheating and mixing 1,4-butanediol and alkylamine, and sending them into a reactor In the process, under the action of catalyst, dehydrogenation and amination are converted into N-alkylpyrrolidone crude material, which is discharged through the material outlet of the reactor; (2) heat exchange of N-alkylpyrrolidone crude material discharged from step (1) with the raw material , and then enter the first gas-liquid separation tank after passing through the first and second two-stage condensers successively, and the incompletely separated gas phase of the first gas-liquid separation tank enters the second gas-liquid separation tank after passing through the third-stage condenser again; (3 ) Purifying the crude product collected in step (2) through a rectification product tower to obtain the product. The catalyst of the invention has high catalytic activity, the yield of the obtained product is ≥98.5%, the conversion rate is ≥99.9%, the purity is ≥99.8%, the water content is ≤50ppm, the free amine is ≤5ppm, and the product quality is high.

Description

technical field [0001] The invention belongs to the technical field of preparation of fine chemical products, and in particular relates to a method for preparing alkylpyrrolidone by amination of 1,4-butanediol. Background technique [0002] Alkylpyrrolidone is an important intermediate in the pharmaceutical and chemical industries. The traditional production process of pyrrolidone uses 1,4-butanediol or maleic anhydride as raw material, and 1,4-butanediol accounts for most of the production capacity. The production process is generally as follows: 1,4-butanediol is first dehydrogenated to γ-butyrolactone, then the crude γ-butyrolactone is purified and reacted with organic monoamine to produce crude pyrrolidone, and finally the product is obtained after rectification , the dehydrogenation of this process is an endothermic reaction, and most of them are gas phase reactions. It is necessary to use heat conduction oil to heat and evaporate 1,4-butanediol and excess hydrogen, whi...

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Problems solved by technology

[0004] The Chinese patent with the notification number CN105237456B discloses a production method of pyrrolidone products, which uses 1,4-butanediol as a raw material to directly produce pyrrolidone through a one-step reaction, and realizes 1,4- Butanediol is converted into pyrrolidone series products in one reaction unit after dehydrogenation and amination reaction. The reactor is divided into upper and lower sections. The reaction temperature of the first section reactor is 190~260℃, and the reaction pressure is 0.5~8.0MPa. The reaction temperature of the second-stage reactor is 230~290℃, and the reaction pressure is 5~15MPa, so a booster pump and a buffer tank are installed between the first-stage reactor and the second-stage reactor, and the upper and lower two-stage reactors The catalysts loaded in the middle are not the same. Although the invention achieves the purpose of carrying out two reactions in one unit, the operation process is cumbersome and the safety factor during the operation of the workers is reduced.

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