Abstract:
This research has studied preparation and characterization of chromium-titanium silicalite-1 catalysts. In our study, every catalyst prepared by incorporation method composed of titanium about 2.22 %mol and chromium not over 0.5 %mol. From characterization, all synthesized samples have MFI structure and orthorhombic crystalline shape. Titanium and chromium atoms in the catalyst framework exist in form of tetrahedral, coordination number of both atoms are 4+ and 5+ respectively. Unlikely, some parts of chromium and titanium atoms are mantled in oxide form on the synthesized catalyst surface. Higher amount of loaded chromium increased the amount of Cr[superscript 5+] in the catalyst framework; in addition, weak acid site ratio and high oxidation state of chromium on the catalyst surface are also increased. Because of those properties, when the catalyst sample with higher loaded chromium is tested by 2-propanol oxidation, high selectivity of propylene isachieved. Only the sample with 0.15 % Cr yields high selectivity to acetone. To investigate on this sample, the surface analysis results suggest that the satisfied dispersion of Ti[superscript 4+] in the catalyst framework should be the reason for its unusual behavior
