Process for preparing tertiary phosphine sulfides and oxides

A method of preparing compounds of the formula:

• ##STR9## wherein R.sup.(1,2) is selected from the group consisting of C.sub.1 to C.sub.7 alkyl;
• the aryl substituted derivatives thereof, said aryl substituted derivatives having 1 or 2 fused rings;
• cycloalkyl 0f 5 - 6 carbons in the ring;
• aryl of up to 3 fused rings;
• biphenyl and the C.sub.1 to C.sub.4 alkyl substituted derivatives of said cycloalkyl, aryl and biphenyl and Z is selected from the group consisting of sulfur and oxygen, provided that when Z is oxygen R.sup.(1,2) is methyl, comprising contacting under at least an autogenous pressure at a temperature of from about 200.degree. C. to about 400.degree. C. a reactant of the formula:
• R.sup.1 ZR.sup.2 (II)
• wherein R.sup.1 and R.sup.2 are the same or different and have the same definition as R.sup.(1,2) as defined above and Z is as defined above, with elemental phosphorus in the presence of a catalyst selected from the group consisting of iodine, alkyl halide, aryl halide and iodide salt.