Preparation of (poly)sulfide alkoxysilanes and novel intermediates therefor

A process for preparing at least one (poly)sulfide alkoxy- and/or halosilane, comprising:

• reacting at least one sulfur reactant (Rs) with at least one alkoxy- and/or halosilane of formula (I):
• in which:
• the symbols R1, which may be identical or different, are each a linear, branched or cyclic alkyl radical having 1 to 20 carbon atoms, an aryl radical having 6 to 18 carbon atoms an alkoxy radical —OR2, wherein R2 is a linear, branched or cyclic alkyl radical having 1 to 20 carbon atoms or an aryl radical having 6 to 18 carbon atoms, an arylalkyl radical or an alkylaryl radical (C6-C18 aryl, C1-C20 alkyl), a hydroxyl radical, or a halogen,
• at least one of these radicals R1 being —OR2, —OH or a halogen, and such radicals R1, when they are neither hydroxyls nor halogens, optionally bear at least one halogen-containing substituent;
• the symbol Y is a monovalent organic functional group, optionally a functional group R3 containing at least one site of ethylenic and/or acetylenic unsaturation, optionally selected from among:
• linear, branched or cyclic alkenyl radicals R3.1 having 2 to 10 carbon atoms,
• linear, branched or cyclic alkynyl radicals R3.2 having 2 to 10 carbon atoms,
• linear, branched or cyclic -(alkenyl-alkynyl) or -(alkynyl-alkenyl) radicals R3.3 having 5 to 20 carbon atoms,
• with the proviso that Y may optionally comprise at least one heteroatom and/or to bear one or more aromatic substituents;
• and
• with the further proviso that, where at least two of the radicals R1 are each halogen, the reaction mixture is essentially free of free-radical initiator(s).

A sulfide alkoxy- and/or halosilane of formula (III):

• in which:
• the symbols R1, which may be identical or different, are each:
• a linear, branched or cyclic alkyl radical having 1 to 20 carbon atoms,
• an aryl radical having 6 to 18 carbon atoms,
• an alkoxy radical —OR2, wherein R2 is a linear, branched or cyclic alkyl radical having 1 to 8 carbon atoms or an aryl radical having 6 to 18 carbon atoms,
• an arylalkyl radical or an alkylaryl radical (C6-C18 aryl, C1-C20 alkyl),
• a hydroxyl radical,
• or a halogen, at least one of such radicals R1 being —OR2, —OH or a halogen, at least one of such radicals R1 not being —OR2, and such radicals R1, when they are neither hydroxyls nor halogens, optionally bearing at least one halogen-containing substituent;
• the symbols R3 and R4, which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from among a linear, branched or cyclic alkyl radical having 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having 1 to 20 carbon atoms;
• the symbols R6 and R7, which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from among a linear, branched or cyclic alkyl radical having 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having 1 to 20 carbon atoms;
• the symbol R11 is —S—CO—R8, —SCS—R8, —SR8, —SCS—NR82 or —SCS—OR8, wherein R8 is:
• a linear, branched or cyclic alkyl radical having 1 to 8 carbon atoms,
• an aryl radical having 6 to 18 carbon atoms,
• an acyl radical —R10—CO—OR8, wherein R10 is an alkylene radical having 1 to 8 carbon atoms,
• a hydroxyalkyl radical having 1 to 8 carbon atoms,
• or an arylalkyl radical or an alkylaryl radical (C6-C18 aryl, C1-C20 alkyl), with the proviso that such radicals R8 may bear at least one halogen-containing substituent.