Study On Synthesis Of Amorphous Alloys And Application In Catalytic Hydrogenation

Recent heightened awareness of the environmental impacts associated with a large proportion of established chemical processes has led to the application of considerable pressures on the chemical industry, both regulatory and consumer driven, to adopt a cleaner and greener approach to manufacture. The amorphous alloy is a kind of new material with short-range ordering while long-range disordering structure. Its unique structural character results in the excellent catalytic properties, such as the high catalytic activity and selectivity, the high resistance to the sulfur poison, especially the less environmental pollution occurred during the catalyst preparation, which is accord with the development trend of current chemical engineering. Therefore, the amorphous alloys have been more concerned gradually.Now, the study on amorphous alloys as catalysts is still in the primary stage, the most investigation is concentrated on their application and fundamental characterization. In previous papers, hydrogenations of benzaldehyde, glucose, cyclopentadiene, adiponitrile, benzene, acrylnitrile, cinnamaldehyde, furfural, and nitrobenzene over various amorphous alloys have been reported. But hydrogenations of halogenated nitrobenzene with amorphous alloy have been not reported up to now. In this paper ultra fine amorphous alloys and supported amorphous alloys have been prepared by chemical reduction. The effect of preparation conditions on catalytic activity and selective of halogenated nitrobenzene hydrogenation have been investigated. The changes in structure of amorphous alloys have been investigated by XRD, TEM, SEM andSAED. The results of halogenated nitrobenzene hydrogenation show that they have better catalytic activity and selectivity than Raney Ni catalyst. The higher activity and better selectivity of the amorphous Ni-B catalyst could be attributed to the higher dispersion of the Ni active sites and was closely related to both the structural and electronic effects on the catalytic property of the Ni active sites. In comparison with other Ni-based catalyst, the Ni-B amorphous alloy catalyst exhibited higher activity and better selectivity for halogenated nitrobenzene. The dehalogenation was less than 4%.Supercritical fluids ( SCFS ) have gained recognition as attractive and environmentally benign media for chemical synthesis. The use of supercritical carbon dioxide ( SCC02) as a reaction solvent has attracted considerable interest during the past decade. SCC02 is highly compressible, and its density and transport properties can be continuously varied from gas-like to liquid-like values by relatively small variations in pressure. But hydrogenations of halogenated nitrobenzene with amorphous alloy have been not reported in SCC02 up to now. In this paper, we study the hydrogenation of amorphous alloy in SCC02.