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5-nitrosalicylic acid preparation process adopting microchannel continuous flow reactor

A technology of microchannel reactor and nitrosalicylic acid, which is applied in the direction of sustainable manufacturing/processing, chemical/physical/physicochemical reactors, nitro compound preparation, etc., to achieve pollution reduction, simple preparation process, and mild conditions Effect

Inactive Publication Date: 2017-11-17
PUYANG VOCATIONAL & TECHN COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by this invention is to provide a kind of technology that continuously prepares 5-nitrosalicylic acid with microchannel reactor, to overcome the defect of traditional reactor, reduce raw material consumption and environmental pollution, improve product yield and production safety And other issues

Method used

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  • 5-nitrosalicylic acid preparation process adopting microchannel continuous flow reactor
  • 5-nitrosalicylic acid preparation process adopting microchannel continuous flow reactor
  • 5-nitrosalicylic acid preparation process adopting microchannel continuous flow reactor

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Effect test

Embodiment 1

[0021] (1) add the aqueous solution of salicylic acid (the mass percentage composition of salicylic acid is 15%) in the storage tank 1, utilize metering pump 3 to inject in the preheating module of microchannel reactor with the speed of 100mL / min; Add the mixed solution of concentrated nitric acid and glacial acetic acid (mass ratio 1:1) in 2, utilize metering pump 4 to inject in another preheating module of microchannel reactor with the speed of 33mL / min; The module reacts, the reaction temperature is controlled at 60°C, and the reaction retention time is 30s, then enters the cooling module, and finally enters the product collector in a continuous flow state.

[0022] (2) The product precipitated after adding water, was filtered and washed with water, and then recrystallized to obtain a white powdery solid with a yield of 79%.

Embodiment 2

[0024] (1) add the aqueous solution of salicylic acid (the mass percentage composition of salicylic acid is 15%) in the storage tank 1, utilize metering pump 3 to inject in the preheating module of microchannel reactor with the speed of 100mL / min; Add concentrated nitric acid in tank 2, utilize metering pump 4 to inject in another preheating module of microchannel reactor with the speed of 15mL / minute; The retention time is 10s, after which it enters the cooling module, and finally enters the product collector in a continuous flow state.

[0025] (2) The product precipitated after adding water, was filtered and washed with water, and then recrystallized to obtain a white powdery solid with a yield of 78%.

Embodiment 3

[0027] (1) add the aqueous solution of salicylic acid (the mass percentage composition of salicylic acid is 15%) in the storage tank 1, utilize metering pump 3 to inject in the preheating module of microchannel reactor with the speed of 50mL / min; Add the mixed solution (mass ratio 1:1) of concentrated nitric acid and glacial acetic acid in tank 2, utilize metering pump 4 to inject in another preheating module of microchannel reactor with the speed of 11mL / minute; Two preheating modules enter simultaneously The reaction is carried out in the mixing module, the reaction temperature is controlled at 65°C, and the reaction retention time is 100s. Then it enters the cooling module, and finally enters the product collector in a continuous flow state.

[0028] (2) The product precipitated after adding water, was filtered and washed with water, and then recrystallized to obtain a white powdery solid with a yield of 80%.

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Abstract

The invention relates to a novel 5-nitrosalicylic acid preparation process adopting a microchannel continuous flow reactor and belongs to the technical field of organic synthesis. According to the process, salicylic acid is taken as a raw material, concentrated nitric acid or a mixture of concentrated nitric acid and glacial acetic acid is taken as a nitrification reagent, the raw material and the nitrification reagent are injected into a reaction module of the microchannel reactor by a metering pump respectively, a material discharged from the reactor is directly injected into ice water, solids are separated out, and 5-nitrosalicylic acid is obtained through water washing. Continuous, efficient, safe and energy-saving industrial production is realized with the microchannel continuous flow process, the preparation process is simple, conditions are mild, retention time is short, product quality is stable, consumed acid content is reduced, yield is high and reaches 75% or higher, and industrial popularization and application are greatly facilitated.

Description

technical field [0001] The invention relates to a process for preparing 5-nitrosalicylic acid using a microchannel reactor, belonging to the technical field of organic synthesis. Background technique [0002] 5‐nitrosalicylic acid (5‐nitrosalicylic acid, CAS: 96‐97‐9), also known as 2‐hydroxy‐5‐nitrobenzoic acid (2‐hydroxy‐5‐nitrobenzoic acid), light yellow crystalline powder , with a melting point of 227-230°C. It is the main intermediate for the synthesis of mesalazine, the active component of the drug sulfasalazine for the treatment of chronic colitis, and an important intermediate for the synthesis of fine chemicals such as dyes and pigments. There are many synthetic routes and improved methods of 5‐nitrosalicylic acid reported in literature at home and abroad, and the commonly used synthetic routes are as follows: [0003] [0004] The commonly used synthetic method is to use salicylic acid as raw material, and then obtain 5‐nitrosalicylic acid through nitric acid o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08C07C205/60B01J19/00
CPCB01J19/0093C07C201/08C07C205/60Y02P20/10
Inventor 石贤举谭冬寒王绍领方娜刘梦辉王亚琳
Owner PUYANG VOCATIONAL & TECHN COLLEGE
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