Preparation of organochlorosilanes

• Main Author: MCENTEE HARRY R
• Format: Patent
• Language: English
• Published: 26.03.1957
• Subjects: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAININGELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN,SULFUR, SELENIUM OR TELLURIUM; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

Organochlorosilanes, particularly diorganodichlorosilanes, are prepared by reacting 2 or more different chlorosilanes, one being of the formula RmSiCl4-m, and the other R1nSiCl4-n, where R is alkyl, R1 is alkyl or aryl, m is 1, 2, 3 or 4, and n is 0, 1, 2 or 3, m and n always being dissimilar, under anhydrous conditions and in the liquid phase, in the presence of aluminium trichloride and of catalytic amounts of a monomeric silane containing hydrogen bonded to silicon, at a temperature of from 50 DEG to 225 DEG C. Examples of alkyl radicals R and R1 are methyl, ethyl, propyl, isopropyl, butyl, amyl and octyl. Examples of aryl radicals which R1 may be are phenyl, tolyl, xylyl, biphenyl and naphthyl. The silane catalysts include those of the formula R11nSiH(4-m-n)Clm, where R11 has the same meanings as R and R1 and in addition may be a halogenated radical, or an alkaryl, aralkyl, cycloaliphatic or higher alkyl radical, and m and n are 0 to 3 and their sum not greater than 3. Amounts of 0.01 to 10% by weight of the total p chlorosilanes are generally used. The amount of aluminium chloride is usually 1 to 15%. The reaction is preferably effected at superatmospheric pressures, e.g. from 15 to 500 p.s.i. In the examples: (1) an equimolecular mixture of Me3SiCl and MeSiCl3 is heated with SiHCl3 and AlCl3 at 150 DEG C. at 150 p.s.i., to yield Me2SiCl2; (2) similar to (1) using MeSiHCl2 as second catalyst; (3) the second catalyst is MeSiHCl2 contained in SiMe4; (5) the second catalyst is PhSiHCl2; (6) a mixture of MeSiCl3, SiMe4, SiHCl3, MeSiHCl2 and Me2SiHCl with small amounts of Me2SiCl2 and Me3SiCl is heated at 58 DEG C. under reflux with AlCl3, to give a mixture containing larger amounts of Me2Si Cl2 and Me3SiCl and no SiMe4; (7) as in (1) using a polysiloxane containing an Si-H group, but with no effect; (8) Me3SiCl is heated with PhSiCl3 using SiHCl3 as second catalyst to give Me2SiCl2 and MePhSiCl2; (9) Me3SiCl is heated with SiCl4 using SiHCl3 as second catalyst, giving Me2SiCl2, and small amounts of MeSiCl3 and MeSiHCl2. Specification 575,667, [Group IV], and U.S.A. Specification 2,647,912 are referred to.