Synthetic process of 2,4-dichloro-5-isopropoxyl phenyl hydrazine

Abstract

The invention provides a synthetic process of 2,4-dichloro-5-isopropoxyl phenyl hydrazine. According to the method, 2,4-dichloro-5-isopropoxyl aniline, ketazine and water are used as raw materials, and the 2,4-dichloro-5-isopropoxyl phenyl hydrazine is synthesized through reaction at a certain temperature. Excessive ketazine and water are added in the reaction process to make the 2,4-dichloro-5-isopropoxyl aniline completely react in a reaction system, reduced pressure distillation is adopted to remove the water and the ketazine after reaction is completed, and a solid substance is washed and dried to obtain the 2,4-dichloro-5-isopropoxyl phenyl hydrazine. Compared with a traditional diazo-reaction process for synthesizing the 2,4-dichloro-5-isopropoxyl phenyl hydrazine, the process includes few reaction steps and is simple, the device requirements are not high, reaction is easy to control, the yield is high, the production process is low, waste discharge is little, and the process is a green and environment-friendly production process.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a synthesis method of 2,4-dichloro-5-isopropoxyphenylhydrazine. Background technique [0002] 2,4-Dichloro-5-isopropoxyphenylhydrazine is an important intermediate for the synthesis of the pesticide oxadiazone, and also an intermediate for the synthesis of various medicines and pesticides, and has wide application value. [0003] At present, the synthesis methods of 2,4-dichloro-5-isopropoxyphenylhydrazine cannot avoid operations such as diazotization, reduction, acidification, and alkali analysis of 2,4-dichloro-5-isopropoxyaniline , these operations have strict requirements on the reaction temperature, diazotization and reduction reactions must be carried out at low temperature, and the addition rate of sodium nitrite solution and the degree of reaction are not well controlled, and side reactions will occur and lead to the generation of by-products. It w...

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Problems solved by technology

[0003] At present, the synthesis methods of 2,4-dichloro-5-isopropoxyphenylhydrazine cannot avoid operations such as diazotization, reduction, acidification, and alkali analysis of 2,4-dichloro-5-isopropoxyaniline , these operations have strict requirements on the reaction temperature, diazotization and reduction reactions must be carried out at low temperature, and the addition rate of sodium nitrite solution and the degree of reaction are not well controlled, and side reactions will occur and lead to the generation of by-products. will affect the following reduction reaction

The process route using sodium sulfite or sodium bisulfite as a reducing agent is relatively mature and has been widely used in the industrial production of 2,4-dichloro-5-isopropoxyphenylhydrazine, but its control conditions are many and the process is complicated. The operation is cumbersome, if you need to use sodium hydroxide solution to adjust the pH value to 6.5~7, if the control is not good, there will be asphalt-like by-products, and the reaction temperature needs to be adjusted many times during the whole process

When stannous chloride is used as reducing agent, not only the price is relatively expensive, but the reaction temperature is low, refrigeration equipment is needed, energy consumption is large, the cost is high, and the yield is not high. SnCl 4 and SnCl 2 Difficult to recycle, easy to cause environmental pollution

[0004] In addition, the existing technology still has the following problems and disadvantages: (1) many reaction steps, complex process, high requirements for equipment, low yield (the total reaction yield is only 70-80%), and high production cost; (2) In the production process, the hydrochloric acid, sodium hydroxide, sulfite or stannous chloride and reaction by-products used eventually enter the wastewater, resulting in a large amount of salt-containing organic wastewater, which is difficult to treat. The treatment cost is high, the waste discharge is large, and it is easy to cause environmental pollution; (3) There are many safety hazards in the diazotization and reduction process, and the concentration of diazonium salt should not be too high, otherwise it will increase the danger of production. The sulfite used will produce sulfur dioxide gas as a by-product, which is toxic and corrosive to a certain extent, and requires high equipment

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