Herbicide Pine Synthesis Process Research

Bentazon is a sort of selective post-emergence herbicide which was researched and developed by BASF Co. Ltd in Germany in 1968. It is used widely in the Soya, corn, rice field and other paddy field and glebe in our country to prevent and cure sedge family and broadleaves, because it has strong adaptability to crop; safety and low toxicity, weed widely, and can be mixed with other herbicide. So bentazon is important herbicide in our country.In this paper, the synthesis processes of herbicide bentazon (the chemical name is 3-methylethyl-2,1,3-benzothiadiazin-(4)-one-2,2-dioxide) has been researched. The optimum synthetic route is made from methyl o-aminobenzoate by summarizing a mass of literatures and comparing different synthetic methods. And the optimum technological conditions, such as reactant proportion, solvent, reacting temperature, reacting time, etc., have been obtained. We acquire the total yield of optimum synthesis process is greater than 75% and the purity is greaten than 87% through a mass of test. The values of yield and purity are better than the report in current literatures. The method of synthesizing bentazon that has been gotten have the features of a simple progress, lower cost, and little environment pollution, which will produce better market prospect in the future.In this paper, the whole reaction process was monitoring by HPLC, at the same time, the chemical structure of bentazon was confirmed by IR, HNMR and other test methods. And the monocrystal of bentazon has been prepared by using solution volatilization method. The molecular structure of bentazon is also confirmed by X-Ray test.