低碳烷烃催化反应机理的固体核磁共振研究  

In situ MAS NMR Spectroscopy Study on Catalytic Reaction Mechanism of Light Alkanes

作　　者：贺鹤勇[1] 邹艳[1] 马卓娜[1] 岳斌[1] 

机构地区：[1]复旦大学化学系,上海市分子催化和功能材料重点实验室,上海200433

出　　处：《物理化学学报》2004年第F08期1024-1031,共8页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20005310);上海市科学技术委员会重大基础研究(03DJ14004);国家重点基础研究发展计划(2003CB615807)资助项目~~

摘　　要：结合实验研究,介绍了13C原位固体核磁共振技术及其在催化反应机理研究中的应用,主要工作包括温和条件下丙烷在镓改性H-ZSM-5上的活化研究,SO2-4/ZrO2、CsxH3-xPW12O40和H-MOR催化剂上正丁烷的异构化反应机理研究,以及利用原位13CMASNMR测定催化剂超强酸性.In situ MAS NMR spectroscopy has been successfully applied to study catalytic re action mecha-nisms.Examples taken from our own study illustrate that the batch-like c ondition in situ MAS NMR technique with strategically 13 C labeled reactants can contribute t o the understanding of reaction path way.The results indi-cate that the ion-exchanged and /or i ts related Ga species are the highly a ctive catalytic components for the a ctiva-tion of propane under mild condition over Ga-modified H-MFI catalysts.Reaction mechanism of skeletal isome r-ization of n-butane over a series of solid acid ca talysts in the acidic strength order of SO 2-4 /ZrO 2 ,Cs x H 3-x PW 12 O 40 and H-MOR was also studied.The mechanism of n-butane isomerization is dependent on the type of solid acid catalyst.Under low temperature,n-butane isomerization onSO 2-4 /ZrO 2 and Cs x H 3-x PW 12 O 40 catalysts proceeds through a monomolecular pathway in t he initial stage of the reaction.At t he later stage,C 3 and C 5 are detected,giving the evidence of the contribut ion of the bimolecular process.On H-MOR catalyst,n-butane isomerization occurs primarily via a bimolecular pathway.Further stud y shows that the kinetics of n-butane isomerization on SO 2-4 /ZrO 2 catalyst at ambient temperature can be well represented by Langmuir-Hin shelwood equation for a re-versible first order surface reaction.The calculated isomerization re action rate constant can be used as a measure of the solid superacidity of the cata lysts.

关 键 词：原位 固体核磁共振 机理 催化反应 低碳烷烃 

分 类 号：O643[理学—物理化学]