Study On Synthesis And Process Of Primisulfuron-methyl

Primisulfuron-methyl which belongs to sulfonylurea herbicide is coming to thearisen herbicide for cornfield because of its strongpoints such as high efficiency, wide use,low toxicity, high selectivity. For the vast market potential, we made the research on itstechnological process and technological conditions to consummate the yield, also made itfor industrialization and economic benefit.Primisulfuron-methyl was synthesized in sequence by cyclization, methylation,difluoromethoxidation, oxidation, ammonolysis and addition reaction with thiourea anddiethyl malonate as starting materials. The products were determined by the ways ofqualitative and quantificational analysis such as HNMR, IR, MS, HPLC.This dissertation made a research on the following factors such as reactiontemperature, time, catalyst and dosage of all kinds of materials. Following dissertationintroduced single factor to consummate the technological process and technologicalconditions, the optimum process parameters can be obtained as follows: for thecyclization, n(thiourea):n(diethyl malonate):n(sodium methoxide)=1:1:1.3, reflux reactiontime 5 hours, yield 94.5%. For the methylation, n(2-Thiobarbituric acid sodiumsalt):n(dimethyl sulfate):n(sodium hydroxide)=1:1.2:3, range of reaction temperature0-10℃, reaction time 4 hours, yield 92.8%. For bis-difloromethoxidation, n(sodiumhydroxide):n(4,6-dihydroxy-2-methyl mercapto pyrimidine)=8:1, dosage of the catalyst A4%, difluorochloromethane 0.5MPa, range of reaction temperature 60-70℃, reaction time4 hours, yield 50%. For oxidization and ammonolysis, technological processrepresentatively, stabilized yield 94.7% and 93.6% respectively. For addition,n(MPSI):n(4,6-Bis(difluoromethoxy)-2-aminopyrimdine)=1.4:1, reaction temperature80℃, reaction time 3 hours, yield 78%. And the total yield was increased to 30.3%.