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Method and device for pipelined preparation of 2-nitro-5-chloro-4-methylbenzenesulfonic acid

A technology of toluenesulfonic acid and toluenesulfonic acid, which is applied in the field of tubular nitration, can solve the problems of poor selectivity and achieve the effects of simple operation, simple post-treatment, and rapid mass and heat transfer

Active Publication Date: 2021-03-23
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since ozone itself is a strong oxidant, it is accompanied by a considerable proportion of oxidation side reactions during the tank-type nitration reaction, and the selectivity is poor.

Method used

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  • Method and device for pipelined preparation of 2-nitro-5-chloro-4-methylbenzenesulfonic acid
  • Method and device for pipelined preparation of 2-nitro-5-chloro-4-methylbenzenesulfonic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0042] The structure of the reaction device is as figure 1 , the length 8 of the reaction pipeline after the inner coating of alumina is 20m, the inner diameter is 4.3mm, and the outer diameter is 6.3mm. The material of the pipeline is corrosion-resistant and high-pressure resistant metal material, which is Hastelloy C-276.

[0043] The operation steps are as follows:

[0044] First connect the device, check the tightness; dissolve the raw material 3-chloro-4-toluenesulfonic acid in the organic solvent methylene chloride, and its volumetric dosage is 8mL / g based on the quality of the raw material 3-chloro-4-toluenesulfonic acid, Add storage tank 2; turn on the cooling system 7 to cool down the cross-type mixing joint 6 to -5~5°C; turn on the heating system 9 to preheat the reaction pipeline 8 that has passed the inner coating of alumina to the reaction temperature of 25°C; turn on the ozone generator 3 , set the ozone flow, adjust the back valve 10, so that the pressure in th...

Embodiment 2

[0046] The structure of the reaction device is as figure 1 , the length 8 of the reaction pipeline after the inner coating of alumina is 25m, the inner diameter is 4.3mm, and the outer diameter is 6.3mm. The material of the pipeline is corrosion-resistant and high-pressure resistant metal material, which is Hastelloy C-276.

[0047] The volumetric amount of dichloromethane is 10mL / g based on the mass of the raw material 3-chloro-4-toluenesulfonic acid, the reaction temperature is 40°C, the pressure in the reaction pipeline 8 is maintained at 0.6MPa, and the 3-chloro-4-toluenesulfonic acid The molar ratio of acid to nitrogen dioxide is 1:1.8, and the reaction residence time is 20min. Other operations are the same as in Example 1. The product was obtained after post-treatment with a yield of 85% and a purity of 99.2% as detected by HPLC.

Embodiment 3

[0049] The structure of the reaction device is as figure 1 , the length 8 of the reaction pipeline after the inner coating of alumina is 30m, the inner diameter is 4.3mm, and the outer diameter is 6.3mm. The material of the pipeline is corrosion-resistant and high-pressure resistant metal material, which is Hastelloy C-276.

[0050] The volumetric amount of dichloromethane is 12mL / g based on the mass of the raw material 3-chloro-4-toluenesulfonic acid, the reaction temperature is 30°C, the pressure in the reaction pipeline 8 is maintained at 0.8MPa, and the 3-chloro-4-toluenesulfonic acid The molar ratio of acid to nitrogen dioxide is 1:1.6, and the reaction residence time is 30min. Other operations are the same as in Example 1. The product was obtained after post-treatment with a yield of 92% and a purity of 99.4% as detected by HPLC.

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Abstract

The invention discloses a pipeline method and device for preparing 2-nitro-5-chloro-4-toluenesulfonic acid. The device comprises a nitrogen dioxide steel cylinder, a storage tank, an ozone generator,a flow pump, a gas flowmeter, a cross mixed joint, a reaction pipeline passing through an alumina interior coating, a cooling system, a heating system, a back pressure valve and a receiving tank. Themethod comprises the following steps: turning on the cooling system and the heating system for preheating; turning on the ozone generator, setting ozone flow, and regulating the back pressure valve; setting the flow pump and the gas flowmeter; and mixing the raw materials, nitrogen dioxide and ozone via the cross mixed joint, enabling the mixture to enter the reaction pipeline passing through an alumina interior coating for carrying out a nitration reaction, and performing after-treatment on the reaction solution, thereby obtaining the 2-nitro-5-chloro-4-toluenesulfonic acid. According to themethod disclosed by the invention, the catalyst alumina is arranged in the pipeline in a coating form, the catalyst is uniformly arranged, the catalytic efficiency is high, the packing does not need to be removed, and the operation is simple and convenient.

Description

technical field [0001] The invention relates to the technical field of tubular nitration, in particular to a method and device for preparing 2-nitro-5-chloro-4-methylbenzenesulfonic acid through pipeline. Background technique [0002] 2-Amino-5-chloro-4-methylbenzenesulfonic acid is a good heat-stable dye intermediate, which is widely used in the manufacture of inks, pigments and ballpoint pens after being salted, and can be used to blend red and blue The effect of color is not easy to fade, the smell is comfortable, and the coating is smooth. Its production process is as follows: use 3-chloro-4-toluenesulfonic acid as raw material, carry out nitration with nitric acid below 30°C, react for 3 hours and then salt it out with saturated brine at 100°C to obtain 2-nitro-5-chloro-p- Toluenesulfonic acid, then add 2-nitro-5-chloro-p-toluenesulfonic acid into water, add acetic acid and iron powder, reduce under boiling conditions, filter the reaction to remove iron powder, add hyd...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C303/22C07C309/40
CPCC07C303/22C07C309/40
Inventor 贾建洪冯东黄佳豪张久明李益珠
Owner ZHEJIANG UNIV OF TECH
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