Physico-chemical properties of MoO3/ZrO2 catalysts prepared by dry mixing for isobutane alkylation and butene transformations

MoO3/ZrO2 catalysts were prepared either by wet impregnation or tableting dry mechanical mixtures of corresponding zirconium hydroxide and molybdenum containing precursors. It was shown that synthesis parameters influence the phase composition, structure, nature and strength of the acid sites. The structural and textural properties of MoO3/ZrO2 catalysts were characterized by a range of techniques including DTA, XRD, N-2-physisorption, pH-measurements, selective adsorption of a series of acid-base indicators and FTIR spectroscopy of adsorbed pyridine. It is shown that an increase in the concentration of MoO3 gave a rise to Bronsted acidity concomitant with an increase of 1-butene conversion in isobutane alkylation and butene dimerization. Introduction of up to 6.6% of MoO3 resulted in sharp changes in physico-chemical properties as well as in catalytic behaviour allowing generation of products with an increased content of C-8 compounds because of alkylation and dimerization. A further increase of MoO3 content to 13.2% predominantly led to isomerization of 1-butene to 2-butene which can be related to elevated Bronsted acidity.