Synthesis method of sodium trichloro pyridinol

Abstract

The invention provides a synthesis method of sodium trichloro pyridinol. The method comprises the following steps: (1) synthesis of butyl chloride: adding a solvent chlorobenzene to an addition reaction kettle, dropwise adding trichloro-acetic chloride and acrylonitrile to the solvent, carrying out addition reaction to generate butyryl chloride; (2) synthesis of pyridine ketone: transferring a solution generated after addition reaction to an enamel reaction still for cyclization, adding sodium hypochlorite, carrying out closed-pressure heat preservation at 50-70 DEG C and carrying out cyclization reaction to obtain the pyridine ketone; and (3) adding a certain amount of water to an alkaline hydrolysis reaction kettle, transferring the solution generated after cyclization reaction to the still, slowly dropwise adding liquid caustic soda with the mass fraction of 30%. According to the method provided by the invention, firstly, the solvent is heated at an addition section; and trichloro-acetic chloride and acrylonitrile are dropwise added at a high temperature, so that the defects of a traditional method that the reaction time is long, yield is low, and a high temperature condition is needed, and raw materials need to be distilled and repeatedly applied are overcome.

Description

technical field [0001] The invention belongs to the field of organic chemistry, and in particular relates to a method for synthesizing heterocyclic organic compounds. Background technique [0002] Sodium triclopyridinate, also known as 2-hydroxy-3,5,6-triclopyridinate sodium, is a synthetic low-toxic, broad-spectrum, low-residue organic phosphorus insecticide and acaricide chlorpyrifos and methyl chlorpyrifos, etc. The main intermediate of pesticide varieties. Sodium triclopyridinate currently industrial production process mainly adopts acrylonitrile and trichloroacetyl chloride to carry out addition reaction in the presence of catalyst and solvent, and the addition product carries out cyclization in the presence of solvent to obtain triclopyridinol, and then in sodium hydroxide Salt formation in the solution to obtain triclopyridin sodium. Due to the difficulty in the synthesis of sodium clopyridinate, the development of the domestic pesticide chlorpyrifos has been restri...

AI Technical Summary

Problems solved by technology

Due to the difficulty in the synthesis of sodium clopyridinate, the development of the domestic pesticide chlorpyrifos has been restricted for a long time

At present, in the production method of sodium clopyridinate in use, there are generally the disadvantages of low yield, high energy consumption and large pollution

[0003] At present, the comparison of various synthetic routes is as follows: the product yield of pyridine liquid phase chlorination method is very low, and a large amount of solvent is consumed during the reaction, so it is not practical to carry out industrialized large-scale production

Pyridine gas-phase chlorination has few steps and high yield, the first two steps are even as high as 90%, but the high-temperature reaction is difficult to operate, and the current domestic fixed-bed reaction technology is immature

The acryloyl chloride method first needs to prepare acryloyl chloride, which has many synthetic steps and a long route. The reaction process also needs to add precious catalyst organophosphorus and organotin, which is not suitable for large-scale industrial production; the phenyl trichloroacetate method needs a large amount of valuable solvent sulfolane, and the side The product is not easy to recover, the yield is low, and it is not easy to produce on a large scale; the raw materials of the trichloroacetyl chloride method are easy to get, the price is cheap, there is no special requirement for the process conditions, the operation is simple, but the reaction route is long

[0004] Since the raw material and process of trichloroacetyl chloride are better than other methods, it is possible to carry out in-depth research on its one-step method, shorten the reaction route, and increase the product yield. It is difficult to increase the reaction temperature under certain conditions. The usual solution is to add a large amount of solvent to increase the reaction temperature. However, this method needs to recycle the solvent so that it will not pollute the environment.

The pressurized "one-pot method" not only has certain requirements for equipment, but also the HCl and H produced by the reaction under airtight conditions 2 O generates a strong acid, resulting in a large amount of by-product tetrachloropyridine, which reduces the yield

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