Study On The Improvement On The Synthesis Technology Of Triazophos

Triazophos, an organophosphate insecticide and acaricide, which can combat wirewonn, is highly effective, poisonous at intermediate lavel and of broad spectrum. Highly killing when touched, having contact and stomach poison,and highly penetrating, it highly effective in killing insect eggs. It is also a good pesitiside for main crops (cotton, grains, vegetables, fruit and so on).Triazophos was first reported by Farbuwerke Hoechst AG in 1970. German chemists Scherer Otto and Mildenberger Kilmer published their patants one after another. Triazophos was started to study in our country in 1980. It is an ideal insecticide in stead of highly toxic pesticides. Triazophos is one of the ten new agrochemical pesticides that expansioned to apply during our country's eighth five-year plan. Now the demand of Triazophos is increasing .My dissertation comes up with two improved methods for the prepation of triazophos . The first method is a process for synthesis of triazophos by phase transfer catalyt in two steps which is more particularly related to improvements in the yield and purity. This method comprises: (1)Synthesis of 1-phenyl-3-hydroxytrizole from urea and phenylhydrazine hydrochloride in presence of HCOOH and (2)Synthesis of triazophos from 1-phenyl-3-hydroxytrizole and (EtO)₂P(S)Cl at 70～75℃ as phase transfer catalysts. The yield and purity of triazophos is 83.4% and 84.6% under selected conditions.This paper put an emphasis on the synthesis of 1-phenyl-3-hydroxytrizole , the selection of amount of catalysts and solvent, and reaction time .The yield and purity of 1-phenyl-3-hydroxytrizole is up to 90.6% andABSTRACTover 99.8%, respectively. This is advanced in our country.The second method employs an only one step for synthesis of triazophos insecticide. That is, Triazophos is prepared by reaction of formic acid with 1-phenyl semicarbazide which prepared from urea and phenylhydrazine hydrochloride in presence of H2SO4 and then followed by reaction of 1-phenyl -3-hydroxytrizole with (EtO)2O(S)Cl. There is no any seperation process in the second method.