Preparation method of 4, 6-dichloropyrimidine

Abstract

The invention provides a preparation method of 4, 6-dichloropyrimidine. The preparation method comprises the following steps: feeding formamide, absolute ethyl alcohol and sodium ethoxide into a container; stirring and heating; dropping diethyl malonate; reflowing and maintaining the temperature after the dropping; recovering the absolute ethyl alcohol and water-containing ethyl alcohol; dropping hydrochloric aqueous solution until the pH (Potential of Hydrogen) of the reaction liquid is 2 to 6; cooling; centrifuging and drying to obtain 4, 6-dihydroxypyrimidine; feeding the 4, 6-dihydroxypyrimidine, dichloroethane and a chlorination catalyst into the container; stirring and slowly heating until reaching reflowing; dropping thionyl chloride; maintaining the temperature after the dropping; then cooling; recovering the dichloroethane; collecting the dichloroethane and finished product; cooling the finished product in a crystallizing kettle; and centrifuging and drying to obtain the finished product of 4, 6-dichloropyrimidine. The preparation method can reduce the risk, is more reasonable in technology, simple and convenient, low in cost, high in quality, environmentally friendly, and more specifically suitable for industrial production, and can reach over 83% of the total reaction yield based on diethyl malonate; and the quality of the 4, 6-dichloropyrimidine meets international standard.

Description

technical field [0001] The invention relates to a method for preparing pesticide raw materials, in particular to a method for preparing 4,6-dichloropyrimidine. Background technique [0002] 4,6-dichloropyrimidine is the raw material for the synthesis of azoxystrobin. The chemical name of azoxystrobin is (E)2-[2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]benzene Base]-3-methyl methoxyacrylate, this product is a methoxyacrylate (Strobilurin) fungicide, highly efficient, broad-spectrum, for almost all fungal kingdoms (Ascomycotina, Basidiomycotina, Flagella Mycotina and Deuteromycotina) diseases such as powdery mildew, rust, glume blight, net spot, downy mildew, rice blast, etc. have good activity. It can be used for stem and leaf spray, seed treatment, and soil treatment. It is mainly used for grain, rice, peanut, grape, potato, fruit tree, vegetable, coffee, lawn, etc. [0003] Currently reported synthetic methods, due to consideration of the yield and manufacturing costs, the cy...

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Problems solved by technology

[0008] However, in the actual production process, it is found that phosgene is dangerous, has high technical requirements, and the yield and product quality are not very high; phosphorus oxychloride production needs phosphorus oxychloride, and phosphorus oxychloride is a highly toxic chemical, and the production Production accidents are easy to occur during the process, the risk is also high, the amount of three wastes is large, separation is difficult, and energy consumption is high

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