Patent ID: 7378556

Claim:
A process for making a thiophosphine compound of formula (I): wherein X represents SH or with R 1 being H or —CH 3 , R and R′ represent, independently from each other, an alkyl radical, an alkoxy radical, an aryl radical or a phenyl radical which may be substituted with one or more alkyl and/or alkoxy groups, n is an integer from 0 to 4, n′ an integer from 0 to 5, x is an integer from 0 to 2, y is an integer from 1 to 5 with the proviso that y+n is an integer from 1 to 5, wherein y=1, X is in para position with regard to phosphorus and represents —SH, the process comprising: a) reacting in the presence of a catalyst a component A of formula: in which R′, n′ and x are defined above with a component B of formula: in which R and n are defined above and G is a blocking radical of the SH function, the molar ratio of components A to B being: 1/3 when x=0 1/2 when x=1, and 1/1 when x=2; b) isolating from step a) a first intermediate compound C of formula: in which R′, n′, R, n, and x are defined above; c) reacting compound C with elemental sulphur; d) isolating from step c) an intermediate compound D of formula: in which R′, n′, R, n, and x are defined above; e) reacting intermediate compound D with an alkaline thiolate in a solvent under reflux; and f) isolating from step e) a thiophosphine monomer of formula (I).