The Synthesis Of Methyl Pirimiphos

With improving environment, many countries ban or limit the use of high toxic pesticide. The development of substitutes for high toxic organic phosphorus pesticide has been a very popular fashion in our country. Extensive,high effectual,safe,low toxic and low residual pyrimiphos-methyl is one of ideal substitutes for high toxic organic phosphorus It recommended by the Food and Agricultural Produce Organization of the United Nations as one of the good-quality agricultural chemicals.The new pesticide, what is more, may be manufactured by using our available equipment, and thus its production needs less investment and cost.This paper studys mainly the synthesis of pyrimiphos-methyl and its intermediates 2-diethylamino-6-methyl-4-pyrimdone, diethylguandine nitrate and diethylguandine surfide, thus obtaining its better technologye in our experiments. The structures of pyrimiphos-methyl and its intermediates are characterized by IR/H-NMR and MSAccording to concerned papers ,we have designed our own way in which diethylguandine nitrate is synthesized from cyanamide. Compared with the s-methyl-iso-thiourea method, our way has advantages of low material cost and high yield. Thus, we select the cyanamide way. The better reaction conditions of the way are as follows: Reaction temperature is 75C ; The ratio of cyanamide to diethylamine(molar ratio)is 1:2.0; Reaction time is 5 hour. Its yisld is 80%.After many experiments, we choose a better way in which 2-diethylamino-6-methyl-4-pyrimdone is synthesized. The better reaction conditions are as follows: Reaction temperature is 110C, Reaction time is 2 hour, The ratio of-3-diethylguandine nitrate to NaOH and ethyl acetodcetate (molar ratio) is 1:1.2:1.2; Its yield is 91%.The better reaction conditions in which pyrimiphos-methyl is synthesized are as follows: The ratio of 2-diethylamino-6-methyl-4-pyrimdone to o,o-dimethyl phosphorochloriclothionate(molar ratio)is 1:1.1; Reaction temperature is 30~35; Reaction time is 2 hour; pH is 8 in the reaction system. Its yield is 90%. The content of crude oil is above 90%. So the total yield is 65.5%.According to the experimental results, we have done the design of the pyrimiphos-methyl project which gives an an output of 500 tons per year.The pyrimiphos-methyl project has been industrialized. The yield of the three steps reaction is 90%^ 95%> and 90% respectively. Its total yield is 77%. Now we are in the leading in our country. The project has been authenticated as a new product in our province...