Patent GB-590654-A (GB)
Title: Improvements in and relating to methods of producing organo-silicon-compounds
IPC: C07F7/16
Filed: 1944-09-27
Abstract: An apparatus for preparing organo-silicon compounds by treating powdered silicon with an organic halide or an alcohol, of which one form is shown in Fig. 1, comprises a vertical reaction tube 3 of restricted cross-section in which powdered silicon delivered through conduit 2 is heated to reaction temperature and is swept upward by a stream of, for example, methyl chloride entering by pipe 1, a chamber 4 provided with a baffle 5 in which the excess of powdered silicon collects on the inclined floor 6, and flows down into a vertical cooling pipe 7 of restricted cross-section communicating with the conduit 2 through the controllng valve 8, and provided with a conduit 25 through which fresh silicon powder is supplied, a cyclone separator 12 which removes the entrained powder, a filter 15 which removes residual silicon dust and a condenser 17 the condensate from which is collected in a vessel 19.  The downward <PICT:0590654/III/1> <PICT:0590654/III/2> flow of the powder in the cooling tube 7 is assisted by the injection of methyl chloride or of another gas, e.g. nitrogen, through conduits 21.  In a modification, Fig. 3, the restricted reaction tube 3 is replaced by a cylindrical vessel 60 of large cross-section in which the reagents are violently agitated, the cooled silicon powder being admitted through a distribution plate 62 from a cooler 61.  In another arrangement silicon powder is withdrawn from the bottom of the reaction vessel for circulation through the cooler.ALSO:<PICT:0590654/IV/1> <PICT:0590654/IV/2> In the preparation of an organic compound containing silicon by the reaction of powdered silicon with an organic halide (cf. Specification 575,667) or alcohol, the control of the exothermic reaction is effected by causing the mixture of reagents to circulate through a reaction zone to a cooling zone.  The silicon may be in the form of a powdered mixture or alloy of silicon with a catalyst or a solid diluent.  Specified organic silicon halides are the methyl, ethyl propyl, butyl amyl, isoamyl hexyl, phenyl, phenylethyl, tolyl, methyl-ethyl-phenyl and ethylene silicon halides and a specified alcohol is methyl alcohol (which yields methyl silicate).  The cooled powder separated from the reaction products may be returned to the reaction zone in quantities sufficient to maintain that zone at the desired temperature.  The action may be continued in successive reaction and cooling zones and may be assisted by the introduction of a gas capable of accelerating the reaction.  In one arrangement (Fig. 1), circulating powdered silicon is delivered through a conduit 2 and is carried upward through the vertical reaction tube 3 initially heated to reaction temperature and of restricted cross-section, by a steam of methyl chloride entering by pipe 1, and the reaction mixture passes into the chamber 4 preferably provided with a baffle 5 in which the excess of powdered silicon collects on the inclined floor 6 and flows into a vertical cooling pipe 7 of restricted cross-ssction communicating with the conduit 2 through a controlling valve 8. Fresh powdered silicon is supplied to chamber 4 through a conduit 25. The gaseous products pass to a cyclone separator 12 which removes entrained powder, and thence to a filter 15, which removes residual silicon dust and a condenser 17 provided with cooling coils 18, the condensate being collected in a vessel 19.  The downward flow of the powder in the cooling tube 7 is assisted by injection of methyl chloride or of another gas, e.g. nitrogen, through conduits 21.  In a modification (Fig. 3), the restricted reaction tube 3 is replaced by a cylindrical vessel 60 of large cross-section in which the reagents are violently agitated, the cooled silicon powder being admitted through a distribution plate 62 from a cooler 61.  In another arrangement silicon powder is withdrawn from the bottom of the reaction vessel for circulation through the cooler.  The spent silicon powder may be decarbonized and reactivated by sintering treatment.