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, N₂-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 Brønsted 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 C₈ 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 Brønsted acidity.