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Method for preparing phenylhydrazine hydrochloride

A technology of phenylhydrazine hydrochloride and chlorobenzene, which is applied in hydrazine preparation, hydrazone preparation, organic chemistry and other directions, can solve the problems of large waste discharge, influence of reduction reaction, and many reaction steps, and achieves less waste discharge, less waste, The effect of easy control of the reaction and few reaction steps

Inactive Publication Date: 2017-09-22
重庆锦杉科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the preparation method of phenylhydrazine hydrochloride usually takes aniline as raw material, and obtains phenylhydrazine hydrochloride through reaction procedures such as diazotization, reduction, and acid precipitation. These procedures have stricter requirements on reaction temperature, and diazotization and reduction The reaction must be carried out at low temperature, and the addition rate of the sodium nitrite solution and the poor control of the reaction degree will cause side reactions and lead to the formation of by-products, which will also affect the following reduction reactions
The process route using sodium sulfite or sodium bisulfite as reducing agent is relatively mature, but its control conditions are many, the process is complicated, and the operation is cumbersome. If it is necessary to use sodium hydroxide solution to adjust the pH value to 6.5~7, if the control is not good Then there will be asphalt-like by-products, and the reaction temperature needs to be adjusted several times in the whole process
When stannous chloride is used as reducing agent, not only the price is relatively expensive, but also the cost is high, and SnCl 4 and SnCl 2 Difficult to recycle, easy to cause environmental pollution
[0004] In addition, the prior art also has the following problems and disadvantages: (1) In the diazotization reaction, the intermediate diazonium salt is extremely unstable and easily decomposed, and must be carried out under low temperature conditions, and refrigeration equipment needs to be equipped, which requires a large investment and can (2) In the reduction reaction, the used reducing agent and its reaction by-products will eventually enter the wastewater, resulting in a large amount of salt-containing organic wastewater. The treatment of this wastewater is difficult and expensive, and waste Large emissions and serious environmental pollution; (3) many reaction steps, complex process, high requirements for equipment, low yield (the total reaction yield is only about 80%), and high production cost

Method used

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  • Method for preparing phenylhydrazine hydrochloride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Put 112.5g of chlorobenzene and 168g of acetonazine into a four-necked flask equipped with stirring, dropping funnel, thermometer and rectifying column, start stirring, heat the solution to 120°C, and slowly add 54ml of water dropwise to the four-necked flask. In the flask, the reaction temperature is controlled at 100°C to 120°C. When the gas generated by the reaction enters the rectification column, acetone is extracted at the column top temperature of 54°C to 58°C, and the water vapor and acetone azine entering the rectification column After condensing, it flows back into the flask to continue to participate in the reaction; after the water is added dropwise, continue the heat preservation reaction, and when the receiver of the rectifying column does not flow out of acetone, the reaction ends, and all the water and acetone in the flask are evaporated with negative pressure. The solid matter was washed with pure water and dried to obtain 137.3 g of phenylhydrazine hydr...

Embodiment 2

[0014] Put 112.5g of chlorobenzene and 196g of acetonazine into a four-necked flask equipped with a stirring, dropping funnel, thermometer and rectifying column, start stirring, heat the solution to 120°C, and slowly add 63ml of water dropwise to the four-necked flask In the flask, the reaction temperature is controlled at 100°C to 120°C. When the gas generated by the reaction enters the rectification column, acetone is extracted at a column top temperature of 54°C to 58°C, and the water vapor and acetone azine entering the rectification column pass through After condensing, flow back to the flask to continue to participate in the reaction; after the addition of water dropwise, continue the insulation reaction, and when there is no acetone flowing out of the rectifying column receiver, the reaction ends, and the water and acetone in the flask are all steamed out with negative pressure. The solid matter was washed with pure water and dried to obtain 138.1 g of phenylhydrazine hy...

Embodiment 3

[0016] Put 112.5g of chlorobenzene and 224g of acetonazine into a four-necked flask equipped with a stirring, dropping funnel, thermometer and rectifying column, start stirring, heat the solution to 120°C, and slowly add 72ml of water dropwise to the four-necked flask In the flask, the reaction temperature is controlled at 100°C to 120°C. When the gas generated by the reaction enters the rectification column, acetone is extracted at a column top temperature of 54°C to 58°C, and the water vapor and acetone azine entering the rectification column pass through After condensing, flow back to the flask to continue to participate in the reaction; after the addition of water dropwise, continue the insulation reaction, and when there is no acetone flowing out of the rectifying column receiver, the reaction ends, and the water and acetone in the flask are all steamed out with negative pressure. The solid matter was washed with pure water and dried to obtain 138.7 g of phenylhydrazine hy...

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Abstract

The invention provides a method for preparing phenylhydrazine hydrochloride. The method comprises the following steps of using chlorobenzene, ketazine and water as raw materials, and reacting at certain temperature, so as to obtain the phenylhydrazine hydrochloride; in the reaction process, adding excessive ketazine and water to enable the chlorobenzene in the reaction system to completely react; after reaction is finished, relieving pressure and distilling to remove water and the ketazine, and washing and drying the remained solid matter, so as to obtain the phenylhydrazine hydrochloride. Compared with the phenylhydrazine hydrochloride prepared by the traditional diazotization reaction technology, the method has the advantages that the number of reaction steps is fewer, the technology is simple, the equipment investment is small, the yield is high, and the energy consumption is low; the recycled byproduct of acetone in the reaction process is the raw material for synthesizing the ketazine, and can be reutilized, the production cost is low, the discharge of emission is small, and a green and environment-friendly production technology is provided.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for preparing phenylhydrazine hydrochloride. Background technique [0002] Phenylhydrazine hydrochloride is an important raw material for organic synthesis. In the production of pesticides, phenylhydrazine hydrochloride is used to synthesize the intermediate 1-phenylsemicarbazide of the organophosphorus insecticide triazophos and the intermediate of pyridazinphos The 1-phenyl-3,6-dihydroxypyridazine is also the intermediate of the new fungicides oxafezone and midazolidin. In addition, phenylhydrazine hydrochloride is used as a raw material for organic synthesis and is also used as a dye , intermediates in pharmaceutical and other industries, and also used as analytical reagents. [0003] At present, the preparation method of phenylhydrazine hydrochloride usually takes aniline as raw material, and obtains phenylhydrazine hydrochloride through react...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/02C07C243/22C07C249/16C07C251/88
CPCC07C241/02C07C249/16C07C243/22C07C251/88
Inventor 王伟
Owner 重庆锦杉科技有限公司