Process for preparing alkane bis-dihalophosphines

Alkane bis-dihalophosphines are prepared by reacting an olefin with a trivalent phosphorus compound having three halogens attached thereto, such as phosphorus trichloride, in the presence of elemental phosphorus under at least autogenous pressure at a temperature of from 150 DEG C. to 350 DEG C. The compounds obtained are useful as intermediates in preparing organophosphorus compounds which can be used as insecticides, fungicides, pharmaceuticals, flame retardant compounds, and in forming metal complexes which are catalyst activators.