The Study Of Supported Ni-Pt-B/γ-Al₂O₃ Amorphous Alloy Catalyst

The amorphous alloy is a kind of new material has been developed in recent years. Because of its unique structure of short-range ordering while long-range disordering and the excellent catalytic properties, besides, its simple preparing process and easily controlled condition. It has theoretic significance and use value to develop it as a new type of catalyst.The supported Ni-Pt-B/γ-Al₂O₃ amorphous alloy catalyst has been prepared by chemical reduction-deposition. Using gas-phase hydrogenation of benzene as probe reaction, the effects of impregnation order, platinum salt, alkali concentration, potassium borohydride concentration and platinum concentration on the hydrogenation activity of the catalyst were systematically studied. And the optimal preparation conditions were determined. The results indicate that the activity of AM-4 catalyst is higher when take chloroplatinic acid as reagents and distilled water as the solvent. Furthermore, with increasing the concentration of potassium borohydride or platinum salt, the hydrogenation activity of the catalyst increased.The effects of the hydrogen benzene ratio, the space velocity and the pressure on the reaction of hydrogenation of benzene were investigated further in this experiment, and the optimal reaction condition was determined by experiment. Under the condition that the Ni concentration 5%, Ni/Pt/B amole of proportion as 150:1:510, the hydrogen benzene ratio 4:1, reaction pressure 0.5MPa, space velocity 1.3h-1, when the reaction temperature was higher than 120℃, the ratio the dearomatization reached 100%.The reasons of deactivation of the catalyst were further studied: (1)At high temperature, the deactivation was resulted from crystallization, and its deactivation process was unreversible. (2)Water and sulfur in the feed were the main reason to cause the catalyst deactivation. (3)The oxidation of air resulted in the deactivation of the catalyst.On the basis of above work, a kind of new and highly effective hydrogenation catalyst was prepared, and the study on the deactivation phenomenon of the catalyst in this thesis is valuable to the increasing of the stability of the catalyst and its application on industry.