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Preparation method of 2-ethylphenylhydrazine hydrochloride

A technology of ethylphenylhydrazine and hydrochloride, which is applied in the field of synthesizing 7-ethyltryptol intermediate o-ethylphenylhydrazine hydrochloride, which can solve the problems of low cost, a large amount of salty wastewater, and a large number of desalination and concentration devices

Inactive Publication Date: 2019-09-06
江苏绿洲化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In the synthesis process of o-ethylphenylhydrazine hydrochloride, o-ethylaniline is mainly obtained through diazotization reaction, sodium pyrosulfite reduction, and hydrochloric acid hydrolysis. The method has cheap raw materials, high yield, and low cost, and is industrialized. The main method of producing o-ethylphenylhydrazine hydrochloride, this process also has a defect, that is, a large amount of saline wastewater is produced, and a large number of desalination and concentration devices are required

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] a, the preparation of sodium nitrite solution

[0021] In a 500L glass-lined reactor, add 100kg of water and 100kg of sodium nitrite, stir, dissolve, and pump to the high tank for later use;

[0022] b. In a 2000L glass-lined reactor, add 150kg of o-ethylaniline, 50kg of water, and 500L of dichloroethane, cool down to below 0 degrees, add 200L of 30% hydrochloric acid dropwise, and continue to drop the prepared nitrous acid Sodium solution, the temperature is -2 to 0 degrees, drop it in about 2 hours, and get the diazonium solution;

[0023] c, preparation of sodium pyrosulfite solution

[0024] In a 3000L glass-lined reactor, add 500L of water (or the previous batch of reduced water layer mother liquor, which can be used in the second batch), 450kg of sodium metabisulfite, stir, and set aside;

[0025] d. Transfer the prepared diazonium solution into the 3000L glass-lined reactor of the sodium metabisulfite solution prepared in advance, and after the transfer is comp...

Embodiment 2

[0028] a, the preparation of sodium nitrite solution

[0029] In a 500L glass-lined reactor, add 100kg of water and 100kg of sodium nitrite, stir, dissolve, and pump to the high tank for later use;

[0030] b. In a 2000L glass-lined reactor, add 150kg of o-ethylaniline, 50kg of water, and 500L of toluene, cool down to below 0 degrees, add 200L of 30% hydrochloric acid dropwise, and continue to add the prepared sodium nitrite solution dropwise. The temperature is -2 to 0 degrees, and the dripping is completed in about 2 hours, and the diazo solution is obtained;

[0031] c, preparation of sodium pyrosulfite solution

[0032] In a 3000L glass-lined reactor, add 500L of water (or the previous batch of reduced water layer mother liquor, which can be used in the second batch), 450kg of sodium metabisulfite, stir, and set aside;

[0033] d. Transfer the prepared diazonium solution into the 3000L glass-lined reactor of the sodium metabisulfite solution prepared in advance, and afte...

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PUM

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Abstract

The invention relates to a preparation method of 2-ethylphenylhydrazine hydrochloride. The preparation method comprises the following steps: adding 100 kg of water and 100 kg of sodium nitrite into a500 L stirring kettle, and performing stirring to achieve dissolving; adding 150 kg of 2-ethylaniline, 50 kg of water and 500 L of an organic solvent into a reaction kettle, lowering the temperature to 0 DEG C or below, dropwise adding 200 L of 30% hydrochloric acid, and continuously dropwise adding the above prepared sodium nitrite solution at -2-0 DEG C in about 2 h after the addition of the 30%hydrochloric acid is finished in order to obtain a diazo solution; adding 500 L of water and 450 kg of sodium pyrosulfite into a 3000 L glass-lined reaction kettle, and performing stirring to achievedissolving; transferring the prepared diazo solution into the reaction kettle filled with the above prepared sodium pyrosulfite solution, and taking out 500 L of the obtained aqueous layer mother liquor; and adding 500 L of hydrochloric acid to acidify the remaining reaction solution, carrying out a reaction at 70 DEG C for 1 h to obtain a product, cooling for crystallizing, centrifuging the system, and drying the obtained filter cake to obtain the dry product with a weight of 143 kg and a molar yield of 85%.

Description

technical field [0001] The invention relates to a preparation method of o-ethylphenylhydrazine hydrochloride, in particular to a method for synthesizing o-ethylphenylhydrazine hydrochloride, a 7-ethyl tryptophan intermediate, using o-ethylaniline as a raw material. Background technique [0002] O-ethylphenylhydrazine hydrochloride, chemical name 2-ethylphenylhydrazine hydrochloride, CAS number: 58711-02-7, molecular formula C 8 h 13 C 1 N 2 , with a molecular weight of 172.66, is a light yellow crystal. It is an important pharmaceutical intermediate and an important pesticide intermediate. In medicine, it is mainly an important intermediate for the synthesis of non-steroidal anti-inflammatory drug etodolac. [0003] In the synthesis process of o-ethylphenylhydrazine hydrochloride, o-ethylaniline is mainly obtained through diazotization reaction, sodium pyrosulfite reduction, and hydrochloric acid hydrolysis. The method has cheap raw materials, high yield, and low cost, an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/02C07C243/22
CPCC07C241/02C07C245/20C07C243/22
Inventor 徐兵夏铁红夏铁平夏治海
Owner 江苏绿洲化工有限公司