Synthesis of Organohalosilane Monomers From Conventionally Uncleavable Direct Process Residue

A catalytic process for producing an organohalosilane monomer composition from a high-boiling residue, said process comprising

• (A) heating the high-boiling residue in the presence of a catalyst comprising (1) one or more heterocyclic amines and/or one or more heterocyclic ammonium halides, and (2) one or more quaternary Group 15 onium compounds,
• optionally in the presence of an organohalide and/or a hydrogen halide and/or an inert gas,
• at a temperature within the range of about 75° C. to about 300° C. under atmospheric pressure or superatmospheric pressure
• to convert the high-boiling residue to an organohalosilane monomer composition containing at least one organohalosilane monomer having a general formula selected from the group consisting of R1SiHX2, R12SiHX, R12SiX2 and R13SiX, R1 being an aromatic, aliphatic, alkaryl or cycloaliphatic univalent hydrocarbyl group, X being a halogen atom selected from the group consisting of fluorine, chlorine, bromine, and iodine, and
• (B) optionally recovering the catalyst,
• wherein the high-boiling residue comprises (1) an uncleavable component containing at least one of tetraorganodihalodisilanes and optionally one or more compounds selected from carbosilanes, organohalopolysilanes, hexaorganodisilanes, and pentaorganohalodisilanes;
• and (2) optionally a cleavable component containing at least one of diorganotetrahalodisilanes and triorganotrihalodisilanes with the proviso that if present, the cleavable component has a concentration less than that of the uncleavable component;
• and
• wherein the quaternary Group 15 onium compound is of the general formula, R4Q+X−, wherein each R is independently an alkyl, cycloalkyl, aryl or alkaryl group of from 1 to 30 carbon atoms, Q is phosphorus, arsenic, antimony and bismuth, and X is a halide selected from the group consisting of F, Cl, Br or I.