Abstract
The aim of this work is to prepare three series of stoichiometric Ti incorporated ammonium salt of 12-molybdophosphoric acid catalysts in order to study the effect of Ti atoms incorporation on physico-chemical properties of the Keggin structure. Catalysts were prepared by increasing the amounts of Ti atoms from 1 to 3 and a consequence decrease of Mo atoms from 11 to 9 to maintain the stoichiometry of the Keggin unit. Prepared catalysts each subjected to calcination at different temperature in the range 300-500°C. The catalysts were characterized by elemental analysis, powder X-ray diffraction, FTIR, TG, N2 gas adsorption and 31P MAS NMR techniques. The redox properties of the Ti incorporated AMPA samples were determined by performing the vapor phase oxidation of benzyl alcohol. Increase of thermal stability, acidity and redox properties with increase of Ti atoms was observed. AMPTi3 catalyst offered highest activity and time on stream analysis revealed that this catalyst is stable under reaction conditions without any deactivation.