Effect of aluminium oxide on the properties of CuMo catalyst in the oxidative dehydrogenation of butene-1 to butadiene

Abstract

Copper molybdate catalysts show catalytic activity for the oxidative dehydrogenation of butene-1, giving butadiene and carbon dioxide as main products, but not for its isomerization to butene-2. The isomerization reaction is catalysed at the centers of acidic nature; thus, aluminum oxide and aluminum molybdate catalysts having such acidic properties may be active catalysts for the conversion of butene-1 to butene-2. The effect of composition on the activity of a Co-Mo system, the influence of surplus trioxide of molybdenum on properties and catalytic activity of a Cr-Mo catalyst, and the effect of molybdenum trioxide on physiochemical and catalytic properties of some molybdates have been studied earlier. Here, the effect of supplementary aluminum oxide giving rise to extra acidic centers in copper molybdate catalyst has been studied with regard to the activity of the catalyst in the reaction of oxidative dehydrogenation of butene-1 to butadiene in the temperature range of 285 to 450 C in a continuous fixed-bed reactor. Introduction of extra acidic centets in copper molybdate catalyst by supplementary aluminum oxide provides a way to establish how to much the acidity of the catalyst surface serves to affect the oxidative dehydrogenation of butene-1 to butadiene. Cu-Mo oxide catalysts with supplementary aluminummore » oxide were prepared by two methods: (1) coprecipitation, and (2) shower impregnation. X-ray analysis of the synthesised catalyst showed that phases of free aluminum oxide were absent. In the diffraction patterns of catalyst samples with different compositions of aluminum oxide prepared by both methods, no shifts in the diffraction maxima were revealed; however, redistributions of the relative intensities of characteristic diffraction peaks were observed. Results are discussed.« less