Hydroisomerization of n-heptane over bimetal-bearing H3PW12O40 catalysts supported on dealuminated USY zeolite

• 来源期刊: 中国科学B辑(英文版)
• 年，卷（期）: 2008,（2）
• 页码范围: 120-127
• 页数: 8页
• 语种: 英文
• DOI: 10.1007/s11426-008-0009-4

摘要

The bimetal-bearing (CePt or LaPt) 12-tungstophosphoric acid (H3PW12O40 (PW)) catalysts supported on dealuminated USY zeolite (DUSY) were prepared by impregnation and characterized by XRD, BET, IR, and H2-chemisorption.Their catalytic activities were tested in the hydroisomerization of n-heptane with a continuous atmospheric fixed-bed reactor.After the steam treatment combined with the acid leaching, as well as the supporting with PW and the bimetals, the DUSY support retains the Y zeolite porosity and the PW well keeps its Keggin structure in catalysts.The doping of Ce into the catalysts enhances the dispersion of Pt on the catalyst surface.The Pt-bearing PW catalysts doped with Ce or La, especially Ce, exhibit much higher catalytic activity and selectivity than the catalysts without dopants at lowered re-action temperatures.At the optimal reaction conditions, i.e., the reaction temperature of 250℃ and WHSV of 1.4 h-1, the catalyst with a Pt loading of 0.4%, PW loading of 10% and a molar ratio of Ce to Pt of 15:1 shows a conversion of n-heptane of 70.3% with a high selectivity for isomerization products of 94.1%.