Patent GB-699658-A (GB)
Title: Improvements in or relating to the manufacture of siloxanes and halosiloxanes
IPC: C08G77/06
Filed: 1951-06-05
Abstract: Organopolysiloxanes, varying from dimers to high polymers, are made by reacting one or more silanes of the formula RnSiX4-n, where R is a hydrogen atom, or an alkyl, aryl, or halogenated aryl hydrocarbon radical, X is fluorine, chlorine, bromine or iodine, and n has a value from 1 to 3, with an oxide of lead, calcium, magnesium, zinc or copper, in amount of at least one equivalent of the metal oxide per equivalent of silicon bonded halogen in the silane(s), in the presence of a solvent selected from liquid saturated aliphatic and aromatic nitriles and nitro-compounds, the solvent being present in amount of at least 1 per cent by weight of the silane(s). Organohalopolysiloxanes are made in a similar way by using the oxide in amount of less than one equivalent of the oxide per equivalent of silicon-bonded halogen in the silane(s).  Silanes specified are trichloro-, dichloro-, methyldichloro-, dimethylfluoro-, phenylmethyldichloro-, diphenyldichloro-, p  propyltrichloro-, octadecyldichloro-, trifluorotolyltrichloro-, bistrifluorotolyldichloro-, chlorophenylmethyldichloro-, xenyltrichloro-and bromoxenyltrichloro - silanes.  Solvents specified are aceto-, propio-, butyrovalero-, benzo-, cyclohexo- and capro-nitriles and nitromethane, -ethane, -propane, -octane, -benzene, -toluene and -cyclohexane.  Cupric or mercuric chloride may be used to catalyze the reaction.  In examples polysiloxanes are prepared from (1) bistrifluorotolyldichlorosilane; (2) together with dimethyldichlorosilane; (3, 9, 14) dimethyldichlorosilane; (4) trimethylchlorosilane; (5) diphenyldichlorosilane; (6) phenyldimethylchlorosilane; (7) dimethyl- and diphenyl-dichlorosilanes; (8) phenyldimethylchloro- and phenylmethyldichloro-silanes; (10-12) phenylmethyldichlorosilane; (13) dimethyldichloro- and methyltrichloro-silanes; and halopolysiloxanes are prepared from (16) phenylmethyldichlorosilane; (17, 18, 19, 21) dimethyldichlorosilane and (20) methylhydrogendichlorosilane. Specification 606,301 is referred to.ALSO:Organosiloxanes, varying from dimers to high polymers, are made by reacting one or more silanes of the formula RnSiX4-n, where R is a hydrogen atom or an alkyl, aryl or halogenated aryl hydrocarbon radical, X is fluorine, chlorine, bromine or iodine and n has a value of 1 to 3, with an oxide of lead, calcium, magnesium, zinc or copper, in amount of at least one equivalent of the metal oxide per equivalent of silicon bonded halogen in the silane or silane mixture, in the presence of a solvent selected from liquid saturated aliphatic and aromatic nitriles and nitro compounds, the solvent being present in amount of at least 1 per cent by weight of the silane(s). Organo-halosiloxanes are made in a similar way by employing the oxide in amount of less than one equivalent of the metal oxide per equivalent of silicon bonded halogen in the silane(s).  Silanes specified are trichloro-, dichloro-, methyldichloro-, dimethylfluoro-, phenylmethyldichloro -, ocphenyldichloro -, propyltrichloro -, octadecyldichloro -, trifluorotolyltrichloro -, bistrifluorotolyldi - chloro -, chlorophenylmethyldichloro -, xenyl - trichloro - and bromoxenyltrichloro - silanes.  Solvents specified are aceto-, propio-, butyro-, valero-, benzo-, cyclohexo- and capro-nitriles, and nitro-methane, -ethane, -propane, -octane, -benzene, -toluene and -cyclohexane.  Cupric or mercuric chloride may be used to catalyse the reaction.  Examples are given of the preparation of <FORM:0699658/IV (b)/1> and (20) Cl.H.CH3Si(OSi.CH3.H)xC. Specification 606,301, [Group IV (a)], is referred to.ALSO:Polysiloxanes, varying from dimers to high polymers, are made by reacting one or more silances of the formula HnSiX4-n, where X is fluorine, chlorine, bromine or iodine, and n has a value from 1 to 3, with an oxide of lead, calcium, magnesium, zinc or copper, in amount of at least one equivalent of the metal oxide per equivalent of silicon bonded halogen in the silane(s), in the presence of a solvent selected from liquid saturated aliphatic and aromatic nitriles and nitrocompounds, the solvent being present in amount of at least 1 per cent by weight of the silane(s). Halogenopolysiloxanes are made in a similar way by using the oxide in amount of less than one equivalent per equivalent of silicon bonded halogen in the silane(s).  Solvents specified are aceto-, propio, butyro-, valero-, benzo-, cyclohexo- and capro-nitriles and nitro-methane, -ethane, -propane, -octane, -benzene, -toluene and -cyclohexane.  Cupric or mercuric chloride may be used to catalyse the reaction.  In Example (15) SiHCl3 is refluxed with CuO in the presence of acetonitrile and CuCl2 to give a non-distillable polysiloxane having the unit formula <FORM:0699658/III/1>