Synthesis of cyclic sulfur silanes
AssigneeWitco Corporation
InventorsKeith J. Weller, Lesley Hwang
Life of this patent
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Abstract
Sulfur-containing norbornanyl silanes are prepared in a simple, solventless manner by the reaction of a norbornenylsilane with sulfur in the presence of a chlorosilane. The resulting silanes may be used without further purification. The silanes were found to give good properties in rubber compositions for low-rolling-resistance tire applications.
Claims10
A process for preparing a reaction mixture containing a sulfur containing norbornanyl silicon compound characterized by the following structure (Formula I):
- [Sy—R]n—SiX4−n Formula I
- wherein each X is chosen from monovalent hydrocarbon groups or hydrolyzable groups;
- y is 1 to 5, when y is 1 the compound is an episulfide, and when y is 2 to 5 the sulfur atoms form a polysulfide wherein each sulfur atom is bonded to another sulfur atom and the terminal valences of the polysulfide are bonded to vicinal carbon atoms;
- n is 1, 2 or 3;
- R is a polyvalent polycycloaliphatic hydrocarbon radical, the process comprising:
- reacting sulfur with an unsaturated silicon compound of the formula
- [R3]n—SiX4−n (Formula Va)
- where R3 is a polycycloaliphatic group containing at least one reactive strained double bond and each X is as defined for Formula I above,
- the sulfur and silicon compound being reacted in the presence of an acid catalyst.
A process for preparing a reaction mixture containing a sulfur-containing norbornenyl silicon compound of the formula
- [Sy—R]n—SiX4−n (Formula I)
- wherein each X is chosen from monovalent hydrocarbon groups, or hydrolyzable groups, y is 1 to 5, when y is 1 the compound is an episulfide, and when y is 2 to 5 the sulfur atoms form a polysulfide wherein each sulfur atom is bonded to another sulfur atom and the terminal valences of the polysulfide are bonded to vicinal carbon atoms;
- n is 1, 2 or 3;
- R is a polyvalent polycycloaliphatic hydrocarbon radical, the process comprising:
- heating a mixture of an unsaturated silicon compound of the formula
- [R3]n—SiX4−n (Formula Va)
- where R3 is a polycycloaliphatic group containing at least one reactive strained double bond and each X is as defined for Formula I above,
- the sulfur and silicon compound being reacted in the presence of an acid catalyst defined by the formula
- [R3]n—SiX4−n (Formula Vb)
- wherein at least one of X is occupied by a halogen, and the remainder are as defined for X, and R3 is a polycycloaliphatic group containing at least one reactive strained double bond;
- wherein the molar ratio of the unsaturated silicon compound to chlorosilane is within the range of from 1000:1 to 10:1 and the molar ratio of unsaturated silane to elemental sulfur is within the range of from 1:3 to 1:4.
Dependencies are inferred from the claim text.