Process for the preparation of 2-dialkoxy phosphinylimino-1,3-dithietane

The process for the preparation of a dithietane having the formula:

• ##STR8## wherein R is a C.sub.1 -C.sub.4 alkyl radical comprising:
• reacting one molar equivalent of a compound of formula:
• ##STR9## wherein R is as defined above;
• M is a cation selected from the group consisting of sodium, potassium and ammonium in the presence of water, with a one to two molar equivalent of a methylene halide selected from the group consisting of methylene bromide and methylene iodide in the presence of 0.1% to 5%, by weight, of the reaction mixture of a phase transfer catalyst selected from the group consisting of a tri-(C.sub.3 -C.sub.12)alkylamine, a tri-(C.sub.3 -C.sub.12)alkylmethylammonium salt, a benzyltri-(C.sub.2 -C.sub.3)alkylammonium salt, a 1,2-dialkyl-3,5-diarylpyrazolium salt, a C.sub.2 -C.sub.4 alkyltriphenylphosphonium salt and a C.sub.1 -C.sub.3 alkylpyridinium salt at a temperature ranging from 25.degree. C to 45.degree. C and a pH of 5 to 8 for a period of time sufficient to essentially complete the reaction, and recovering said dithietane compound.