Abstract: The supported Pd/Al2O3 membrane samples with controllable Pd loading were prepared by impregnation with Pd-containing microemulsion. Pd nanoparticles in the microemulsion and in the pore structure of Al2O3 membrane were characterized by scanning electron microscopy and atomic absorption spectroscopy. The catalytic performance of the Pd/Al2O3 membrane samples for the hydrogenation of1,5-cyclooctadiene over a catalytic contactor membrane reactor was measured. The results showed that the Pd loading amount, impregnation methods, calcination temperature, and pore size of the Al2O3 support affected the activity and selectivity of the Pd/Al2O3 membrane samples. The optimal preparation conditions for Pd/Al2O3 membrane with high activity and higher selectivity for cyclooctene were that the Pd nano-particles were slowly deposited from Pd-containing microemulsion while the Al2O3 membrane support was circularly impregnated with Pd-containing microemulsion, the calcination temperature was 300 ℃, and the pore size of the Al2O3 support was 1.9 μm.

Key words: palladium, alumina, membrane reactor, microemulsion, cyclooctadiene, hydrogenation, cyclooctene, cyclooctane