Direct synthesis of LPG from synthesis gas over Pd-Zn-Cr/Pd-β hybrid catalysts

The reaction of synthesis gas to liquefied petroleum gas (LPG) over Zn-Cr-based hybrid catalysts was systematically investigated in this paper. The results show that the synergistic effect, existed in the Zn-Cr-based methanol synthesis component and beta zeolite, results in the high performance of hybrid catalysts for synthesis gas to LPG. Active metal Pd in the beta zeolite mainly play the role of olefin hydrogenation, which promotes the reaction of the title-mentioned overall reaction. The ratio of SiO2/Al2O3 in Pd-beta has a large influence on the stability of hybrid catalysts for syngas to LPG. As the SiO2/Al2O3 ratio increases, CO conversion slightly decreases, however, the catalytic stability of Zn-Cr-based hybrid catalysts is largely improved. The characterization results indicated that during the reaction, the decreasing of acidic sites is the main reason of catalyst deactivation. (c) 2007 Elsevier B.V. All rights reserved.