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Preparation method of salicyl hydrazide

A technology for salicylic hydrazide and salicylic hydrazide finished products, applied in the field of preparation of salicylic hydrazide, can solve problems such as environmental pollution, low reaction yield, complicated post-treatment, etc., and achieves the advantages of reducing production cost, shortening process steps, and eliminating esterification reaction. Effect

Inactive Publication Date: 2018-08-28
李博强
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantages of the synthesis of salicylhydrazide in the prior art are as follows: in the first step of the esterification reaction, due to the use of concentrated sulfuric acid as a catalyst, there is strong corrosion, high equipment requirements, and a large amount of acidic organic waste water will be produced. After neutralization with alkali The salt content and COD content in the wastewater are high, the wastewater treatment is difficult, the treatment cost is high, the waste discharge is large, and it is easy to cause environmental pollution; in the second step hydrazinolysis reaction, there are many side reactions and impurities, and the post-treatment is complicated , low reaction yield, high production cost and other issues

Method used

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  • Preparation method of salicyl hydrazide

Examples

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Effect test

Embodiment 1

[0012] With salicylic acid 138g, content is the hydrazine hydrate 173g of 80% and ZnCl 2 / CuCl 2 Put 14g of composite catalyst into a four-neck flask equipped with stirring, thermometer and rectification column, start stirring, heat up to reflux, when steam enters the rectification column, extract water vapor at the column top temperature of 98°C to 100°C, react After 4 to 6 hours, when there is no condensed water flowing out from the top of the rectifying column, the reaction is ended, and the remaining hydrazine hydrate is all evaporated and recovered by vacuum distillation, then the flask is cooled to normal temperature, an appropriate amount of pure water is added to the flask, and the stirring is started. After the solid matter in the flask was stirred into a slurry, it was put into a centrifugal filter to filter, and then the filter cake was washed with an appropriate amount of pure water. The washed filter cake was centrifugally dehydrated and dried to obtain 145.3 g of...

Embodiment 2

[0014] With 138g of salicylic acid, 190g of hydrazine hydrate and ZnCl with a content of 90% 2 / CuCl 2 Put 21g of the composite catalyst into a four-necked flask equipped with stirring, thermometer and rectification column, start stirring, heat up to reflux, when steam enters the rectification column, extract water vapor at the column top temperature of 98°C to 100°C, and react After 4 to 6 hours, when there is no condensed water flowing out from the top of the rectifying column, the reaction is ended, and the remaining hydrazine hydrate is all evaporated and recovered by vacuum distillation, then the flask is cooled to normal temperature, an appropriate amount of pure water is added to the flask, and the stirring is started. After the solid matter in the flask was stirred into a slurry, it was put into a centrifugal filter to filter, and then the filter cake was washed with an appropriate amount of pure water. The washed filter cake was centrifugally dehydrated and dried to o...

Embodiment 3

[0016] With 138g of salicylic acid, 210g of hydrazine hydrate and ZnCl with a content of 98% 2 / CuCl 2 Put 27g of the composite catalyst into a four-necked flask equipped with a stirring, thermometer and rectifying column, start stirring, heat up to reflux, when steam enters the rectifying column, extract water vapor at a column top temperature of 98°C to 100°C, and react After 4 to 6 hours, when there is no condensed water flowing out from the top of the rectifying column, the reaction is ended, and the remaining hydrazine hydrate is all evaporated and recovered by vacuum distillation, then the flask is cooled to normal temperature, an appropriate amount of pure water is added to the flask, and the stirring is started. After the solid matter in the flask was stirred into a slurry, it was put into a centrifugal filter to filter, and then the filter cake was washed with an appropriate amount of pure water. The washed filter cake was centrifugally dehydrated and dried to obtain ...

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Abstract

The invention provides a preparation method of salicyl hydrazide. According to the preparation method, the salicyl hydrazide is prepared by a one-step method by using salicylic acid and hydrazine hydrate as raw materials and adopting a ZnCl2 / CuCl2 composite catalyst. The hydrazine hydrate is kept excess in a reaction system, and water produced during the reaction is continuously separated from thereaction system, so that the progress of a hydrazide reaction is effectively promoted, the reaction time is shortened, and the reaction yield is increased. Compared with the prior art, the preparation method provided by the invention has the advantages as follows: by the preparation method, a technology is simple, the reaction yield is high, product impurities are few, the purity is high, the catalyst can be recycled, an esterification reaction is omitted, technological steps are reduced, the production cost is reduced and waste discharge is reduced, so that the preparation method is an environment-friendly production technology.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a preparation method of salicylhydrazide. Background technique [0002] Salicylhydrazide is a white needle-like crystal with a melting point of 147-148°C, slightly soluble in cold water, soluble in hot water and organic solvents such as alcohol and ketone. Salicylhydrazide has anti-mold effect, and a series of new fungicides with high efficiency and low toxicity of salicylhydrazide derivatives can be synthesized from salicylhydrazide. In addition, salicylhydrazide is also an important intermediate for the synthesis of various medicines and pesticides. [0003] At present, the preparation method of salicylic hydrazide mainly uses salicylic acid, methanol and hydrazine hydrate as raw materials, and obtains salicylic hydrazide through two-step reactions (esterification reaction and hydrazinolysis reaction): the first step is to dissolve salicylic acid and met...

Claims

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Application Information

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IPC IPC(8): C07C241/04C07C243/38
CPCC07C241/04C07C243/38Y02P20/584
Inventor 李博强
Owner 李博强
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