SELECTIVE HYDROGENATION OF OLEFINIC BONDS IN STYRENE-ISOPRENE STYRENETRIBLOCK COPOLYMER BY PALLADIUM ACETATE CATALYST

Homogeneous catalytic hydrogenation of styrene-isoprene styrene triblo ck copolymer (SIS) has been carried out selectively at the carbon-carb on double bond in the presence of palladium acetate catalyst under mil d conditions. Degree of hydrogenation has been calculated with the hel p of infrared and nuclear magnetic resonance spectroscopic techniques. Almost 90 mol % complete hydrogenation has been achieved at 60-degree s-C under 1.4 MPa hydrogen pressure, 40 mg catalyst (for 2 g of polyme r) in chloroform-acetone solution for 1 h. (C) 1993 John Wiley & Sons, Inc.