Patent ID: 6075157
Filing Date: 2000-06-13
Classification: C07F

Abstract:
A process for producing O,S-dimethyl phosphoramidothioate comprising:a. isomerizing O,O-dimethyl phosphoramidothioate in the presence of dimethyl sulfate at a temperature of from about 20.degree. C. to about 80.degree. C., to form a reaction mixture containing from about 70% to about 85% by weight of O,S-dimethyl phosphoramidothioate, and the balance being unreacted O,O-dimethyl phosphoramidothioate and by-products; andb. passing said reaction mixture through a wiped film evaporator at a temperature of from about 55.degree. C. to about 120.degree. C. and a pressure of from about 3 to about 10 mm Hg, with the distillate containing O,S-dimethyl phosphoramidothioate, unreacted O,O-dimethyl phosphoramidothioate and by-products, and the residue containing O,S-dimethyl phosphoramidothioate in an amount greater than the amount of O,S-dimethyl phosphoramidothioate contained in said reaction mixture of step a).