Highly active palladium nanocatalyst for selective hydrogenation of 1,5-cyclooctadiene under atmospheric H2 pressure

An ionic liquid [CH3(OCH2CH2)22N+Et3][p-CH3C6H4SO3−] was synthesized and employed for stabilizing Pd nanocatalyst, which possesses the thermoregulated phase-separable property. The as-prepared Pd nanocatalyst was applied for the selective hydrogenation of 1,5-cyclooctadiene under atmospheric H2 pressure. The >99% conversion of 1,5-cyclooctadiene with 95% selectivity towards cyclooctene was achieved under the optimal reaction conditions. The Pd nanocatalyst could be reused for six cycles without evident loss in conversion and selectivity. The turnover frequency of 4232 h−1 is greater than those of previously reported Pd nanocatalyst under atmospheric H2 pressure.