REDUCTION IN SULFANE CHAIN IN BIS-(SILYLORGANYL) POLYSULFANE

PROBLEM TO BE SOLVED: To reduce the length of a sulfane chain in the subject compound useful as a reinforcing agent, etc., for rubbers by reacting a bis(silylorganyl) polysulfane with an anhydrous sulfide and an organic halogenated silicon com pound in a specific molar ratio. SOLUTION: A bis-(silylorganyl)polysulfane represented by formula I Z is a group represented by formula II [R is a 1-5C alkyl, a 5-8C cycloalkyl, benzyl or a (substituted)phenyl; R is a 1-5C alkoxy, a 5-8C cycloalkoxy, phenoxy or benzyl] or formula III or IV; Alk is a 1-10C bivalent hydrocarbon, a group represented by formula V [(n) is an integer of 1-4]; (x) is an integer of 3-8, especially 4-6} is reacted with an anhydrous sulfide represented by the formula; Me2 S (Me is an alkali metal, 1 equiv. of an alkaline earth metal, zinc or ammonium) and an organosilicon compound represented by the formula Z-Alk-Y (Y is Cl or Br) by selecting the molar ratio of the poluysulfane represented by formula I to the anhydrous sulfide represented by the formula; Me2 S according to the S content of the polysulfane to be partially desulfurized to thereby reduce the length of the sulfane chain.