Patent ID: 6271407
Filing Date: 2001-08-07
Classification: C07F

Abstract:
A process for the preparation of hydrosilanes from polysilanes, comprising contacting gaseous hydrogen under pressure with polysilanes of formula (I):R.sub.a H.sub.b Si.sub.n X.sub.2n+2-a-b (I)in which:the R radicals are identical or different and are selected from the group comprising:linear or branched C.sub.1 -C.sub.6 alkyls, aryls, linear or branched C.sub.1 -C.sub.6 alkoxyls, a trifluoropropyl radical or a trimethylsiloxyl radicalthe X radicals are halogens which are identical to or different from one anothern=2 to 20a=0 to 2n+2b=0 to 2n+2a+b=0 to 2n+2in order to obtain monosilanes of formula (II):R.sub.c H.sub.d SiX.sub.4-c-d (II):in which:R and X are as defined abovec=1, 2, 3 or 4d=0, 1 or 2c+d=2, 3 or 4wherein polysilane (I) and hydrogen are brought into contact in the presence of a catalytic system comprising--A-- on the one hand, at least one precursor of at least one hydrogenation catalyst, this precursor A being selected from salts of at least one transition metal, the anionic or neutral ligands of which are devoid of 7-acceptor orbitals;--B-- and, on the other hand, at least one aid for dissolution of the precursor A in the reaction medium, this aid B being selected from nucleophiles which are soluble in an aprotic medium;with the exclusion of a reducing agent.