碳四歧化反应网络的调控与催化机制研究

国家西气东输工程的实施和国际市场液化天然气的大量输入对液化气资源的转化利用提出新的要求，多相催化剂上烯烃歧化反应是解决碳四烯烃高附加值利用的重要手段。本课题拟对比和澄清不同结构碳四烯烃分子在Mo基催化剂上的歧化活化机制，在此基础上实现碳四烃定向生产不同高附加值烯烃催化剂的制备。以优化的Mo/Al2O3为模型催化剂，采用氘代烯烃对金属卡宾物种的滴定方法，对比不同结构碳四烯烃分子生成金属卡宾物种及后继反应性能的差异，结合DFT理论计算揭示反应分子与活性中心结构的关联；研究反应温度、烯烃分压对碳四分子歧化反应动力学的影响，由此设计1-丁烯出发分别定向制备乙烯（3-己烯）与丙烯（2-戊烯）的高效催化剂。针对活泼异丁烯分子参与的歧化网络，通过催化剂的功能化修饰，实现碳四烯烃异构与歧化活性中心的匹配，选择性促进丁烯制丙烯与异戊烯反应的进行，为碳四烯烃的高值化利用提供有效的理论支撑。

Olefin metathesis has received increasing attention and is now considered one of the most important C-C bond formation reactions. From practical reasons, development of new metathesis pathways on basis of the direct utilization of C4 olefin streams to value-added olefin is very attractive both in industrial and academic contexts. This proposal focuses on the elucidation of competitive metathesis reaction network of different C4 olefin molecules and elemental reaction pathways over heterogeneous catalysts. Activation ability and the following reactivity of C4 olefin with different molecular structure on Mo/Al2O3 model catalyst will be compared with the assistance of deuterated olefin titration. Combined with DFT modeling, definite active site structure corresponding to different olefin is expected to be obtained. On basis of the above work, metathesis of 1-butene to ethene or propene will be adjusted according to market demanding. Through optimizing the support and active metal precursors, metathesis of butene and iso-butene to propene and iso-pentene is expected to be promoted with high selectivity. Besides, deactivation mechanism of the catalyst from impurities in the C4 effluent may be clarified on basis of the in-situ IR and EPR experimental results which may further guide the scale-up production of non-noble olefin metathesis catalysts over heterogeneous system.