Patent GB-981815-A (GB)
Title: A process for the exchange of silicon bound halogens
Inventor: KANNER BERNARD
IPC: C07F7/12
Filed: 1961-06-22
Abstract: A process for the redistribution of silicon-halogen bonds in organo-silicon compounds comprises forming a reaction mixture comprising at least one monomeric silane represented by the formula <FORM:0981815/C3/1> wherein R is a divalent hydrocarbon radical; Y is a hydrogen or halogen atom, or a -CN, <FORM:0981815/C3/2> or - NO2 radical; G is a monovalent hydrocarbon radical; R1 is a hydrogen atom, or a vinyl or a Y-R-radical; X is a halogen atom, e is 0, 1, 2 or 3; f is O or 1 and the sum of e and f is not greater than 3, or bistrichlorosily benzene; and a tertiary amine, a trihydrocarbyl phosphine, or a silylamine represented by the formula GmSi(NG2)4-m wherein G is a monovalent hydrocarbon radical and m is 0, 1, 2 or 3, there being present in the reaction mixture at least one silicon-fluorine bond and at least one other different silicon-halogen bond; and reacting the mixture to cause redistribution of the halogen atoms attached to silicon.  Many halogen-containing silanes, tertiary amines, phosphines and silylamines are specified.  The process may be performed in a batchwise or continuous manner and may be used in the preparation and/or purification of halogen-containing silanes.  In examples the following compounds are prepared by the process of the invention: (1) trimethylfluorosilane from trimethylchlorosilane, phenylmethyldifluorosilane and trihexylamine; (2) nitrophenylmethyldichlorosilane from nitrophenylmethyldifluorosilane silicon tetrachloride and triheptylamine; phenyl-trichlorosilane from phenyltrifluorosilane, silicon tetrachloride and trihexylamine; (3) phenyldiethylphosphine (4) or trimethyl-N,N-diethylaminosilane (5); (6) methyldifluorosilane and methylchlorofluorosilane from phenyltrifluorosilane, methyldichlorosilane and triheptylamine; (7) bis(nitrophenyl) dichlorsilane from bis(nitrophenyl)difluorosilane, silicon tetrachloride and triheptylamine; (8) g -cyanopropylmethyldichlorosilane from g -cyanopropylmethyldifluorosilane, silicon tetrachloride, triheptylamine and trilaurylamine; (9) phenylmethyldibromosilane from phenylmethyldifluorosilane, silicon tetrabromide and phenyldiethylphosphine; (10) phenylmethyldi-iodosilane from phenylmethyldifluorosilane, silicon tetraiodide and phenyldiethylphosphine; (11) g -cyanopropylmethyldibromosilane from g - cyanopropylmethyldifluorosilane, silicon tetrabromide and 4-picoline; (12) nitrophenylmethyldichlorosilane from nitrophenylmethyldifluorosilane, phenylmethyldichlorosilane and tributylamine; (13) nitrophenyltrichlorosilane and phenyltrifluorosilane (which may be nitrated to nitrophenyltrifluorosilane and recycled) from nitrophenyltrifluorosilane, phenyltrichlorosilane and tributylamine; (14) bis(nitrophenyl)dibromosilane and diphenyldifluorosilane (which may be nitrated and recycled) from bis(nitrophenyl)difluorosilane and diphenyldibromosilane and trihexylamine; (15) g -cyanoisobutylmethyldichlorosilane and g -chloroisobutylmethyldifluorosilane (which may be reacted with NaCN and then recycled) from g -cyanoisobutylmethyldifluorosilane, g  - chloroisobutylmethyldichlorosilane and tributylamine; (16) g -cyanopropylmethyldichlorosilane and methyldifluorosilane (which can be reacted with allyl cyanide and recycled) from g  - cyanopropylmethyldifluorosilane, methyldichlorosilane and tributylamine.  In other examples the process is used for the purification of diphenyldichlorosilane (17), trimethylchlorosilane (18), phenylmethyldichlorosilane (19), g -cyanopropylmethyldichlorosilane (20), methyldichlorosilane (21), methylvinyldichlorosilane (22), dimethyldichlorosilane (23), and dimethyldibromosilane (24).  Phenylmethyldifluorosilane, phenyltrifluorosilane, diphenyldifluorosilane, and g -chloroisobutylmethyldifluorosilane are prepared in examples by reacting the appropriate chlorosilanes with Na2SiF6 in tetrahydronaphthalene.  Nitrophenylmethyldifluorosilane and nitrophenyltrifluorosilane are prepared in examples by reacting the corresponding phenylsilanes in chloroform with a mixture of fuming nitric acid and concentrated sulphuric acid.  g  - cyanoisobutylmethyldifluorosilane is prepared in an example by reacting the chloroisobutyl compound with sodium cyanide in dimethylformamide containing potassium iodide.  g  - Cyanopropylmethyldifluorosilane is prepared in an example by reacting methyldifluorosilane and allyl cyanide in the presence of ethanolic chloroplatinic acid.