Studies on the organic reactions using the catalysts supported mesoporous materials

Abstract

With transition metals, Pd, Pt, Co, loaded on the mesoporous materials, organic reactions (hydrogenation, hydrogenolysis, Heck reaction, and Pauson-Khand reaction) were investigated and new selectivity, compared with the reaction of other catalyst, was found. Pd@MCM48 selectively hydrogenolyzed benzyl ether of molecules including double bonds while other Palladium catalysts have no selectivity between hydrogenation and hydrogenolysis. And benzyl bromide makes hydrogenolysis to be 3 times faster, but it has no effect on hydrogenation. Pd@MCM48 hydrogenolyzed completely 1° benzyl ether but the hydrogenolysis of 2° and 3° benzyl ether wasn’t observed in the mixture of 1°, 2° and 3° benzyl ethers. Hydrogenation of the olefin including benzyl ether with Pt/CMK-1 gave no debenzylated product until the hydrogenation finished, while the hydrogenation with Pt/C gave 10% debenzylated product. The relative rates of hydrogenation with Pt/CMK-1 of di- and tri-substituted olefins were about two orders of magnitude slower than mono-substituted olefin. In the case of Pt/C, the relative rates of di- and tri-substituted olefins were about 3 times slower than mono-substituted olefin. The heterogeneous Pauson-Khand reaction with $Co_2(CO)_8$/MCM48 and $Co_2(CO)_8$/CMK-1 gave 20% yield and 26% yield. In according to the mechanism of Pauson-Khand reaction only one carbonyl group is participated. But we observed that only 0.35 equivalent of $Co_2(CO)_8$ in DME under a Ar atm gave 70% yield.