负载型钼基催化剂上甲烷、乙烷无氧芳构化反应研究  

Methane and Ethane Aromatization without Using Oxidant over Supported Mo Catalysts

作　　者：姜辉[1] 崔巍[1] 王林胜[1] 徐奕德[1] 

机构地区：[1]中国科学院大连化学物理研究所催化基础国家重点实验室

出　　处：《分子催化》1998年第5期335-341,共7页Journal of Molecular Catalysis(China)

摘　　要：研究了不同载体钼基催化剂上甲烷、乙烷的无氧芳构化反应．在所采用的载体（Ａｌ２Ｏ３、ＳｉＯ２、ＨＺＳＭ－５）中，ＨＺＳＭ－５具有最佳性能．对甲烷的芳构化反应，Ｍｏ／ＨＺＳＭ－５催化剂表现出较高的活性和芳烃选择性；而Ｍｏ／Ａｌ２Ｏ３或Ｍｏ／ＳｉＯ２催化剂则相对较差．对于乙烷的反应，钼物种的存在更有利于甲烷（ＨＺＳＭ－５或ＳｉＯ２上）或乙烯（Ａｌ２Ｏ３上）的生成，芳烃选择性相对较低．钼物种较强的断键能力可能是使甲烷Ｃ－Ｈ键活化的原因．在各种载体的催化剂上，对甲烷反应均有诱导期，而对乙烷反应却没有．ＴＰＳＲ实验表明，对于甲烷的反应，苯生成前的诱导期内出现ＣＯ２和Ｈ２Ｏ的双峰结构，这表明催化剂体系钼物种的还原是分步进行的；而对于乙烷的反应，却没有此结构．甲烷反应的诱导期应与催化剂体系钼物种的还原有关．Methane and ethane aromatization without using oxidant over various supported Mo catalysts has been studied. Among all the used supporters (Al 2O 3, SiO 2, HZSM 5), HZSM 5 is the best one. For methane reaction, Mo/HZSM 5 catalyst shows higher reactivity and aromatics selectivity than Mo/Al 2O 3 or Mo/SiO 2 catalysts. For ethane reaction, however, the existence of molybdenum species is favorable for production of methane ( over Mo/HZSM 5 or Mo/SiO 2 ) or ethene (over Mo/Al 2O 3 ), which results in lower aromatics selectivity. The good cracking ability of molybdenum species may be responsible for the activation of methane. It is found that all the reactions using methane as reactant show induction period prior to the initiation of benzene formation, while those using ethane as reactant do not do so. TPSR results show that there is doublet structure on the corresponding curves of CO 2 and H 2O for methane reaction, which demonstrates the step reduction of molybdenum species. As for ethane reaction, however, there is no such phenomenon. Therefor, we suggest that induction period of methane reaction ( prior to the initiation of benzene formation) should be related to the reduction of molybdenum species.

关 键 词：甲烷 乙烷 无氧芳构化 钼基 催化剂 芳构化 

分 类 号：O625.1[理学—有机化学] O643.36[理学—化学]