Method for producing polysulphane-silanes by means of phase transfer catalysis

A process for preparing polysulfane silanes of the formula I

• (R1)3-mR2mSi—R3—Sx—R3—SiR2m(R1)3-m I
• where R1 are the same or different and are a C1-C10-alkoxy group, phenoxy group, or
• alkyl polyether group —(R′—O)rR″ where R′ is the same or different and is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic, or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon group, r is an integer from 1 to 30 and R″ is unsubstituted or substituted, branched or unbranched, monovalent alkyl, alkenyl, aryl, or aralkyl group,
• R2 are the same or different and are C6-C20 aryl groups, C1-C10 alkyl groups, C2-C20 alkenyl groups, C7-C20 aralkyl groups, or halogen,
• R3 are the same or different and are a branched or unbranched, saturated or
• unsaturated, aliphatic, aromatic, or mixed aliphatic/aromatic divalent C1-C30 hydrocarbon
• group,
• and m is the same or different and is 0, 1, 2, or 3, x is 2-10,
• by reacting at least one silane of the formula II
• (R1)3-mR2mSi—R3-Hal II
• where Hal is Cl, Br, or I
• with M(SH)y and/or MzS and/or MgSh and/or sulfur,
• where in the formula M(SH)y, y is 1 or 2, and M is Na or K when y is 1, and M is Ca or Mg when y is 2,
• and in the formula MzS, z is 1 or 2, and M is Ca or Mg when z is 1, and M is Na or K when z is 2,
• and in the formula MgSh, g is 1 or 2, and Mis Ca or Mg when g is 1, and M is Na or K when g is 2,
• h is a natural number from 1 to 10,
• in the presence of a base, an aqueous phase and a phase transfer catalyst of the
• formula III
• where Y is an element of main group 5,
• R4, R5, R6, and R7 are identical or different and are —(CH2)k CH3 alkyl radicals, with
• k=0-9, or wherein any of two substituents selected from the R4, R5, R6, and R7 groups can form a ring with one or two ring closures —(CH2)n— with n=2-5, between two substituents selected from the R4, R5, R6, and R7 groups, and X− is F−, I−, Cl−, Br−, ClO4−, PF6−, BF4−, (C6H5)4B−, H2PO4−, CH3SO3−, C6H5SO3−, HSO4−, NO3−, or ½ SO42−,
• wherein at least one carrier vapour distillation and/or ozone treatment is performed during or after the reaction,
• wherein the vapour distillation and/or ozone treatment removes degradation products of the phase transfer catalyst which are arsine, phosphine, or amines, and
• wherein the base is Na2CO3 or NaOH,
• wherein the carrier for the at least one carrier vapor distillation comprises a stream of steam and nitrogen,
• wherein the process comprises the ozone treatment, and
• wherein the ozone treatment comprises treatment with pure ozone or ozone produced in an ozone generator.