Diquat synthesizing and refining technology

Abstract

The invention belongs to the technical field of pesticide preparation synthesis, and specifically relates to a diquat synthesizing and refining technology. According to the diquat synthesizing and refining technology provided by the invention, a diquat aqueous solution is prepared by the steps such as desolvation, synthesis, layering, filtering, regulation of pH value, extraction and distillation.

Description

technical field [0001] The invention belongs to the technical field of pesticide preparation synthesis, and specifically relates to a diquat synthesis and refining process. Background technique [0002] Diquat, the chemical name is 1,1'-ethylene-2,2'-bipyridine dibromide, is a non-selective contact herbicide and desiccant developed by British Syngenta Chemical Company. It is also one of the most widely used herbicide products in the world, second only to glyphosate and paraquat in global sales and usage. [0003] Diquat is generally used as a conductive contact-killing biogenic herbicide, which can be quickly absorbed by green plant tissues, and will lose its activity soon after contact with the soil. It is mostly used for weeding in fields, orchards, non-arable land, and before harvesting. It can be used as stem and leaf withering of potatoes and sweet potatoes; in places where grass weeds are serious, it is better to use diquat and paraquat together. Diquat generally exi...

AI Technical Summary

Problems solved by technology

But in prior art method, adopt reflux insulation reaction more, make whole reaction cycle reach more than 18h; The solid obtained by the filtration process not only cannot remove the impurities generated during the reaction, which affects the reaction yield, but also because the dibromoethane raw material has strong corrosion and volatility, it will increase the tail gas during the filter press drying process. The difficulty of processing makes the consumption of dibromoethane raw material higher, which increases the production cost; moreover, after the prior art method obtains the solid, it is dissolved and extracted with water, which requires multiple toluene extractions and the pH value of the material is adjusted by hydrochloric acid. Only qualified materials can be obtained. On the one hand, the consumption of the extractant is too high, and the use of hydrochloric acid also increases the impurities in the materials. At the same time, the processing steps are also relatively cumbersome, which seriously affects the synthesis efficiency of diquat and increases the cost of refining.