Trimerization of isobutene over WOx/ZrO2 catalysts Original Research Article

Trimerization of isobutene to produce isobutene trimers has been investigated over WOx/ZrO2 catalysts that were obtained by wet-impregnation and successive calcination at high temperatures. Very stable isobutene conversion and high selectivity for trimers are attained over a WOx/ZrO2 catalyst obtained by calcination at 700 °C. From the XRD study it can be understood that tetragonal ZrO2 is beneficial for stable performance; however, monoclinic ZrO2 is not good for trimerization. Nitrogen adsorption and FTIR experiments suggest that amorphous WOx/ZrO2 is inefficient catalyst even though it has high surface area and high concentration of acid sites. The observed performance with the increased selectivity and stable conversion demonstrates that a WOx/ZrO2 having tetragonal zirconia, even with decreased porosity and acid sites, is one of the best catalysts to exhibit stable and high conversion, high selectivity for trimers and facile regeneration.