Selective hydrogenation of olefinic bonds in styrene‐isoprene‐styrene triblock copolymer by palladium acetate catalyst

Homogeneous catalytic hydrogenation of styrene‐isoprene‐styrene triblock copolymer (SIS) has been carried out selectively at the carbon‐carbon double bond in the presence of palladium acetate catalyst under mild conditions. Degree of hydrogenation has been calculated with the help of infrared and nuclear magnetic resonance spectroscopic techniques. Almost 90 mol % complete hydrogenation has been achieved at 60°C under 1.4 MPa hydrogen pressure, 40 mg catalyst (for 2 g of polymer) in chloroform‐acetone solution for 1 h.