常温常压下五元杂环的催化加氢反应

Investigation on Catalytic Hydrogenation of Five-Membered Heterocycles at Normal Temperature and Pressure

考察了常温常压下吡咯、呋喃和噻吩的催化加氢反应 ;用紫外吸收光谱、气相色谱和酸碱度测定分析了反应物质 ;用比表面积测定、X射线衍射、透射电镜及高分辨电镜表征了催化剂 .结果表明 ,在纳米量级的镍基催化剂作用下 ,双键五元杂环的加氢反应过程是多反应同时进行 :主要有环上双键先加氢生成四氢化物单键环 ,继而开环加氢生成若干小分子气体 ;也有直接开环反应 .总体上是在还原条件下实现降解反应 .超声波的介入有利于保持催化剂的活性 .对反应机理进行了探讨 .

Catalytic hydrogenation of pyrrole, furan and thiophene was investigated. It is verified that many reactions take place simultaneously for the hydrogenation of five-membered heterocycles on nanometer nickel-based catalyst. The double-bond of the ring is hydrogenated to single-bond ring of tetrahydro-compound at first, then the ring is broken and low-molecular gases are produced; while, there are also some reactions in which the ring is broken directly. In general, these reactions are degradation under reduction. UV absorbance spectroscopy, GC and pH detection are used to analyze the reactants and products, and the catalyst is characterized by specific surface area measurement, XRD, TEM and high-resolution electron microscopy (HREM). The experimental results indicate that the main path for hydrogenation of 5-membered heterocycles is on the cycle and open the cycle later; and that the employment of ultrasonic wave is of benefit to the maintenance of catalytic activity. Furthermore, the reaction mechanism has also been investigated.