T 1652 (OTTO) Thiophosphoryl chloride, 98% Cas 3982-91-0 - used in the synthesis of O-ethyl dichlorothiophosphate. T 1652 (OTTO) Thiophosphoryl chloride, 98% Cas 3982-91-0 - used to thiophosphorylate organic compounds, such as to produce insecticides.