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Structure-reactivity correlations in sulphated-zirconia catalysts for the isomerisation of α-pinene
被引:87
作者:
Ecormier, MA
Wilson, K
Lee, AF
[1
]
机构:
[1] Univ Hull, Dept Chem, Kingston Upon Hull HU6 7RX, N Humberside, England
[2] Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England
基金:
英国工程与自然科学研究理事会;
关键词:
solid acid catalysts;
clean technology;
green chemistry;
zirconia;
alpha-pinene;
D O I:
10.1016/S0021-9517(02)00150-1
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
A range of mesoporous sulphated zirconias with tuneable structural and catalytic properties have been prepared by direct impregnation. The surface sulphate coverage can be readily varied, achieving a maximum value of similar to0.2 monolayers. High-temperature calcination induces the crystallisation of tetragonal zirconia while suppressing the monoclinic phase and enhances surface acidity. Superacid sites only appear above a critical threshold SO4 coverage of 0.08 mL (corresponding to 0.44 wt% total S). Sulphated zirconias show good activity towards alpha-pinene isomerisation of under mild conditions. Conversion correlates with the number Bronsted acid sites, while the selectivity towards mono- versus polycyclic products depends on the corresponding acid site strength; superacidity promotes limonene formation over camphene. (C) 2003 Elsevier Science (USA). All rights reserved.
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页码:57 / 65
页数:9
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