Verfahren zur Herstellung aequilibrierter Gemische von Polydiorganosiloxanylsulfaten

摘要

1306311 Equilibrated polydiorganosiloxanyl sulphates TH GOLDSCHMIDT AG 6 Jan 1971 [28 Jan 1970] 688/71 Headings C3S and C3T Equilibrated polydiorganosiloxanyl sulphates of the formula wherein n is 2 to 20, m is 1 to 10, R is the same or different in the molecule or molecule mixture and denotes a methyl or ethyl group which may be substituted with a group inert to sulphuric acid and some of which may be replaced by aromatic groups or groups of the formula pairs of which may form through intermolecular or intramolecular condensation groups of the formula are prepared by (a) separating sulphuric acid from an equilibrated mixture of compounds of the formula which mixture of compounds is in equilibrium with sulphuric acid and compounds of the required formula; or (b) reacting organopolysiloxanes having structural units of the formula (wherein b is 0 to 20, a is 1 to 105 when b is 0 and a is 1 to 20 when b is greater than or equal to 1) with 10-5 to 0À5 mole of sulphur trioxide per silicon atom in the presence of a trace amount of a proton acid, or with 10-5 to 0À5 mole of chlorosulphonic acid per silicon atom; or (c) reacting silylhalide group terminated organopolysiloxanes of the formula (wherein a and b are as defined for (c) and X denotes a halogen atom, some of which may be replaced by sulphate groups, one sulphate group replacing two halogen atoms) with about 0À5 mole of sulphuric acid per silylhalide group. If desired the polydiorganosiloxanylsulphates obtained by methods (a), (b) and (c) may be further reacted with a diorganopolysiloxane such as (wherein x is 3 to 7 and R denotes methyl or ethyl) in the presence of a trace amount of a proton acid, suitably having -OSO 3 H groups. Separation of the sulphuric acid in method (a) may be effected either by forming a poorly soluble salt therewith or by dissolving the equilibrium mixture in a solvent such as dichloromethane in which the sulphuric acid is insoluble. Uses.-Equilibration catalysts for preparation of organopolysiloxanes, catalysts for polymerization of dialkylcyclopolysiloxanes, and water-repellent impregnation agents for glass, ceramics, textiles and paper.