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Method for continuously preparing pentafluorophenol by micro-reactor

A microreactor and pentafluorophenol technology are applied in the field of continuous preparation of pentafluorophenol in microreactors, which can solve the problems of inability to meet purity requirements, decrease in yield, increase in by-products of polysubstituted phenols, etc., and achieve convenient product purification and production. The effect of low cost and high reaction yield

Active Publication Date: 2020-04-28
DALIAN QIKAI MEDICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is easy to operate and has a high yield. However, the simple impurity in the product is still 0.5-0.8%, which cannot meet the purity requirement of more than 99.9% as a liquid crystal intermediate.
After multiple distillations of the product, the yield drops significantly, especially when the method is scaled up to tens of kilograms, the by-products of multi-substituted phenols increase significantly

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add potassium hydroxide 52.5g (0.94mol) and water 78.0g to the microreactor lye kettle to form a solution, and add hexafluorobenzene 75.0g (0.40mol) to the microreactor raw material kettle. The working temperature of the microreactor is set at 160°C, the outlet of the microreactor pipeline is controlled by a quantitative pressure control valve, and the working pressure of the microreactor pipeline is set at 0.6Mpa. Potassium hydroxide aqueous solution and hexafluorobenzene are all pumped in by the metering pump according to the volume flow ratio of 2:1, and it takes 5 hours to pump them all in, and the residence time in the microreactor is 3 minutes. Collect the system liquid at the outlet of the heat exchanger of the microreactor, add 146g of 30% hydrochloric acid, and steam distill to obtain 103g of oil layer. The oil layer detection system consists of: water 30%, pentafluorophenol 70%, rectification and dehydration to obtain 72.0g of pentafluorophenol. The yield was ...

Embodiment 2

[0030] Add potassium hydroxide 271g (4.83mol) and water 321g in the microreactor lye kettle to form a solution, and add hexafluorobenzene 300g (1.61mol) in the microreactor raw material kettle. The working temperature of the microreactor is set at 140°C, the outlet of the microreactor pipeline is controlled by a quantitative pressure control valve, and the working pressure of the microreactor pipeline is set at 0.8Mpa. Potassium hydroxide aqueous solution and hexafluorobenzene are all pumped in by the metering pump according to the volume flow ratio of 2.2:1, and it takes 4 hours to pump them all in, and the residence time in the microreactor is 5 minutes. Collect the system liquid at the outlet of the microreactor heat exchanger, add 516g of 30% hydrochloric acid, and steam distill to obtain 405g of oil layer. The oil layer detection system consists of: water 30%, pentafluorophenol 70%. Rectification and dehydration gave 284g of pentafluorophenol. The yield was 95.7%, and th...

Embodiment 3

[0032] Add potassium hydroxide 95g (1.69mol), sodium hydroxide 68g (1.70mol) and water 320g to the microreactor lye still to form a solution, and add hexafluorobenzene 300g (1.61mol) to the microreactor raw material still. The working temperature of the microreactor is set at 150°C, the outlet of the microreactor pipeline is controlled by a quantitative pressure control valve, and the working pressure of the microreactor pipeline is set at 0.8Mpa. Potassium hydroxide aqueous solution and hexafluorobenzene are all pumped in by the metering pump according to the volume flow ratio of 2:1, and it takes 4 hours to pump them all in, and the residence time in the microreactor is 5 minutes. Collect the system liquid at the outlet of the microreactor heat exchanger, add 516g of 30% hydrochloric acid, and steam distill to obtain 411g of oil layer. The composition of the oil layer detection system is: water 30%, pentafluorophenol 70%. Rectification and dehydration gave 288g of pentafluor...

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Abstract

The invention relates to a method for continuously preparing pentafluorophenol by a microreactor, which belongs to the field of chemical production processes. The method comprises the following steps:simultaneously pumping hexafluorobenzene and an inorganic alkali aqueous solution into a micro-channel reactor by using a metering pump respectively, and mixing for a hydrolysis reaction; keeping thetemperature of the reactor at 130-170 DEG C, controlling and maintaining the pressure of a pipeline at 0.5-1.0 Mpa by an outlet quantitative pressure control valve, connecting an outlet with a heat exchanger, obtaining an aqueous solution of pentafluorophenolate from the outlet of the heat exchanger, adding hydrochloric acid steam, distilling to obtain an oil layer, and rectifying and dehydratingthe oil layer to obtain pentafluorophenol. The method is simple in process, low in cost, free of amplification effect and capable of achieving continuous production.

Description

technical field [0001] The invention relates to a method for continuously preparing pentafluorophenol in a microreactor, belonging to the field of chemical production technology. Background technique [0002] 2,3,4,5,6-Pentafluorophenol, referred to as pentafluorophenol, is an important fine chemical intermediate, which is mostly used to prepare pentafluorophenyl active esters for peptide synthesis, thereby promoting the formation of peptide bonds; It can be used as an intermediate of medicine, pesticide and liquid crystal material. [0003] At present, the synthetic method of pentafluorophenol mainly contains: (1), catalytic oxidation method, as patent CN106588577A, take pentafluorobenzene as raw material, high-copper MCM-41 molecular sieve is catalyst, hydrogen peroxide is oxidant, and reaction generates pentafluorophenol. The catalyst preparation process of this process is complicated, the cost is high, and it is not suitable for industrialized production; (2), etherific...

Claims

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Application Information

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IPC IPC(8): C07C37/02C07C39/27B01J19/00
CPCC07C37/02B01J19/0093C07C39/27
Inventor 张绥英张洪学姜殿平
Owner DALIAN QIKAI MEDICAL TECH
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