摘要 |
In a first embodiment of the present invention, poisoning or deactivation of conventional homogeneous catalysts to be used in hydrogenation of the backbone unsaturation in liquid monofunctional and difunctional-terminated conjugated diene polymers, is prevented by reacting a blocking agent compound with the functional end groups present in these polymers. More specifically, subsequent to formation of a selected starting material monofunctional or difunctional-terminated conjugated diene polymer, a suitable blocking agent is reacted with the functional end groups of the polymer enabling relatively inexpensive titanium, iron, cobalt, or nickel-based homogeneous catalysts to be used in hydrogenating the backbone unsaturation of the polymer to a high degree. Subsequent to hydrogenation, the polymer is subjected to conventional hydrolysis using a mineral acid or base to remove the blocking groups and return the hydrogenated conjugated diene polymer to its original functionality. In a second embodiment, conventional homogeneous catalysts based on cobalt, nickel, titanium, or iron are utilized to hydrogenate low molecular weight liquid copolymers and homopolymers to a high degree. More particularly, butadiene-alkenylpyridine and butadiene-acrylate liquid copolymers and butadiene homopolymers are formed in a conventional manner are hydrogenated using such catalysts. |