Olefin production from polyols via deoxydehydration (DODH) was carried out over Ag-modified CeO 2 -supported heterogeneous Re catalysts with H 2 as a reducing agent. Both high DODH activity and low hydrogenation ability for C=C bonds were observed in the reaction of erythritol, giving a 1,3butadiene yield of up to 90 % under "solvent-free" conditions. This catalyst is applicable to other substrates such as methyl glycosides (methyl α-fucopyranoside: 91 % yield of DODH product; methyl β-ribofuranoside: 88 % yield), which were difficult to be converted to the DODH products over the DODH catalysts reported previously. ReO x -Ag/CeO 2 was reused 3 times without a decrease of activity or selectivity after calcination as regeneration. Although the transmission electron microscopy energy-dispersive X-ray spectroscopy and X-ray absorption fine structure analyses showed that Re species were highly dispersed and Ag was present as metal particles with various sizes from well-dispersed species (< 1 nm) to around 5 nm particles, the catalysts prepared from size-controlled Ag nanoparticles showed similar performance, indicating that the catalytic performance is insensitive to the Ag particle size.

Hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by...

CeO2-supported Ru (Ru/CeO2) worked as an effective and reusable heterogeneous catalyst for the selective dissociation of the C-N bond in amides, particularly primary amides, with H2 in water solvent at low reaction temperature of 333 K, and high yields of the corresponding alcohols were obtained from primary amides.

No abstract

Selective reduction of alkylbenzenes, which are supplied by refining heavy hydrocarbons, to methylbenzenes by selective CÀC hydrogenolysis was accomplished by Ru/CeO 2 catalyst. Hydrogenolysis of ethylbenzene was carried out with gas-phase fixed-bed flow reactor and various noble metal catalysts. The catalyst with high Ru loading (4 wt%) on CeO 2 support precalcined at high temperature (1073 K; Ru(4)/CeO 2 1073 catalyst) showed both good activity and selectivity to toluene. The yield of toluene reached 65 %-C in the conditions of 533 K and H 2 partial pressure of 0.075 MPa. Hydrogenolysis of other alkylbenzenes including p-ethyltoluene, propylbenzene and cumene was also carried out. Hydrogenolysis of C aryl -C alkyl bond and hydrogenation of benzene ring was slow in all substrate cases. Hydrogenolysis of p-ethyltoluene can give p-xylene as the main product (highest yield: 53 %-C). These high yields of methylbenzenes make a marked contrast to the traditional bifunctional hydrocracking systems which preferably dissociate C aryl -C alkyl bond in alkylbenzenes. Characterization of Ru catalysts suggests that the block-shaped Ru particles with small size (< 2 nm) in Ru(4)/CeO 2 1073 give good catalytic performance. Too strong interaction between Ru species and CeO 2 support induced by decreasing the loading amount rather gives ring-hydrogenation activity and decreases methylbenzenes selectivity.[a] S.