ORGANIC PHOSPHORUS COMPOUNDS: II: PREPARATION OF CHLOROMETHANEPHOSPHONYL DICHLORIDE

Hydroxymethanephosphonic acid was prepared by treating paraformaldehyde with phosphorus trichloride at atmospheric pressure and subsequent hydrolysis of the resultant complex. Chloromethanephosphonyl dichloride was obtained by chlorination of hydroxymethanephosphonic acid with thionyl.chloride in the presence of pyridine. On the other hand hydroxymethanephosphonic acid combined slowly with phosphorus pentachloride to give the hitherto unknown dichlorophosphorylmethanephosphonyl dichloride, Cl 2 P(O)OCH 2 P(O)Cl 2 , together with chloromethanephosphonyl dichloride. The structure of dichlorophosphorylmethanephosphonyl dichloride was confirmed by its conversion with phosphorus pentachloride at 78 °C into chloromethanephosphonyl dichloride and phosphorus oxychloride. The preparation of chloromethanephosphonyl dichloride by interaction of paraformaldehyde and phosphorus trichloride in an autoclave at 250 °C was studied in reference to the influence of heating time on the yield.