Method for preparing benzil by oxidation of benzoin in microreactor

A microreactor and benzoin technology, applied in the field of chemical reaction, can solve the problems of low production efficiency, long reaction time, poor safety, etc., and achieve the effects of high production efficiency, short reaction time and high safety

Active Publication Date: 2019-01-18
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process has the problems of long reaction time (8~12h), low production efficiency, cumbersome operation, and poor safety.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Carry out experiment according to this method, dissolve benzoin in the ethyl acetate and be made into the solution that mass fraction is 5%, control reaction temperature is 100 ℃, and pressure is 0.3MPa, and concentration is 37% nitric acid in membrane dispersion microreactor. The solution is dispersed into the benzoin solution, the molar ratio of nitric acid / benzoin is 1.4, the residence time of the mixed material is controlled to be 5min, and finally the material enters the phase separation tank for phase separation, and the obtained solution is analyzed. The conversion rate of benzoin is 99.5%. The selectivity is 99.8%.

Embodiment 2

[0023] Carry out experiment according to this method, dissolve benzoin in dimethylformamide and be made into the solution that mass fraction is 10%, control reaction temperature is 120 ℃, and pressure is 0.5MPa, and concentration is 65% in membrane dispersion microreactor. The nitric acid solution is dispersed in the benzoin solution, the nitric acid / benzoin mol ratio is 2.0, and the residence time of the mixed material is controlled to be 3min, and finally the material enters the phase separation tank for phase separation, and the obtained solution is analyzed. The selectivity of diacetyl is 99.9%.

Embodiment 3

[0025] Carry out experiments according to this method, dissolve benzoin into benzil to form a solution with a mass fraction of 20%, control the reaction temperature at 150°C, and pressure at 0.8MPa. The solution is dispersed into the benzoin solution, the molar ratio of nitric acid / benzoin is 1.8, the residence time of the mixed material is controlled to be 2min, and finally the material enters the phase separation tank for phase separation, and the obtained solution is analyzed. The conversion rate of benzoin is 99.6%. The selectivity is 99.9%.

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Abstract

The invention belongs to the technical field of chemical reaction engineering, and discloses a method for preparing benzil by oxidation of benzoin in a microreactor. The method utilizes efficient mixing and excellent mass transfer and heat transfer performance of the microreactor, nitric acid is used as a dispersion phase in the microreactor, benzoin is dissolved into an inert solvent as a continuous phase, the dispersion phase and the continuous phase are mixed to initiate reaction, the reaction is completed in a retardation tube behind the microreactor, and the separation of a product from unreacted nitric acid is achieved in a phase separation tank. In the method, a conversion rate of 99.8+% and high selectivity of 99.5+% can be achieved in 5 minutes, so that a reactor volume can be significantly reduced, and the safety of a reaction process can be improved.

Description

technical field [0001] The invention belongs to the technical field of chemical reaction, and in particular relates to a method for preparing benzil by oxidation of benzoin in a microreactor. Background technique [0002] Benzil, also known as diphenyl ethylene dione, bibenzoyl, can be used in insecticides, photosensitizers, photocuring agents for photocurable coatings and pharmaceutical intermediates, etc. It is an important organic synthesis intermediate and organic chemical raw material , It is widely used in industries such as medicine, pesticide and electronics. [0003] At present, the commonly used technology in industry is the nitric acid oxidation method, the oxidant used is concentrated nitric acid, and the reactor used is a stirred tank. The process has the problems of long reaction time (8-12 hours), low production efficiency, cumbersome operation, and poor safety. It is of great significance to develop a new method for the continuous and efficient oxidation of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C49/784C07C45/29
CPCC07C45/29C07C49/784
Inventor 骆广生张吉松邓建钱晓春王兴兵王兵
Owner TSINGHUA UNIV
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