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

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.