Shape-selective hydrogenation of naphthalene over zeolite-supported Pt and Pd catalysts
Shape-selective hydrogenation of naphthalene over zeolite-supported Pt and Pd catalysts
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DOI：
10.1016/0920-5861(96)00033-8
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发表时间：
1995-12
期刊：
影响因子：
5.3
通讯作者：
A. Schmitz;G. Bowers;Chunshan Song
中科院分区：
文献类型：
--
作者：
A. Schmitz;G. Bowers;Chunshan Song
将沸石负载的铂、钯催化剂用于高反式/顺式十氢萘(Dehn)异构体的加氢反应。研究了四种沸石：三种不同SiO_2/Al_2O_3比(17、21和38)的氢丝光沸石(HM)和HY沸石(SiO_2/Al_2O_3比为5.0)。催化剂的选择性与金属和沸石有关。因此，催化剂的组成可以被定制以选择性地生产顺式或反式-德恩。例如，铂/HY催化剂对顺式-Dehn的选择性特别高(80%)，与所有其他催化剂不同的是，它不能促进顺式-Dehn的异构化。另一方面，Pd/HM21催化剂实现了Dehn异构体之间的平衡，在200℃时得到了约93%的反式Dehn。总的来说，Pd催化剂的初始选择性高于铂催化剂。Pd催化剂上顺式-Dehn异构化为反式-Dehn的反应速度较快。反式-Dehn的选择性随着分子筛上弱酸中心比例的增加而增加(用正丁胺的TPD重量法测量)。未发现金属微晶尺寸(由X射线衍射线加宽确定)与Dehn异构体选择性之间的相关性。
Zeolite-supported Pt and Pd catalysts were used to effect naphthalene hydrogenation with high trans/cis decahydronaphthalene (DeHN) isomer selectivity. Four zeolites were studied: three hydrogen-mordenites (HM) with different SiO2/A12O3ratios (17, 21 and 38) and HY (SiO2/A12O3of 5.0). Catalytic selectivity was found to depend on both the metal and the zeolite. Consequently, the catalyst composition could be tailored for selective production of either cis-DeHN or trans-DeHN. For example, Pt/HY showed especially high selectivity (80%) for cis-DeHN and unlike all other catalysts tested, did not promote the isomerization of cis-DeHN. On the other hand, equilibrium between the DeHN isomers was achieved with Pd/HM21, giving ca. 93% trans-DeHN at 200°C. In general, Pd catalysts showed higher initial selectivity for trans-DeHN than Pt catalysts. Also, the isomerization of cis-DeHN to trans-DeHN was more rapid on Pd catalysts. Selectivity for trans-DeHN increased with the fraction of weak acid sites on the zeolite (measured gravimetrically, using TPD of n-butylamine). No correlation between metal crystallite sizes (determined from XRD line-broadening) and DeHN isomer selectivity was found.