A comparative study of molybdenum promoted vanadium phosphate catalysts towards epoxidation of cyclohexene

• High to excellent yield (91%) of epoxide was obtained with Mo-VPO.
• The synergetic effect between Mo and V made the active phase, VPO, more stable.
• The catalyst did not show any significant change in the activity after 40 h.
• The presence of couple V4+/V5+ on the surface of Mo-VPO facilitates the reaction.
• The present investigation is interesting in the industrial point of view.

This article describes our efforts in developing molybdenum promoted vanadium phosphate (Mo-VPO) catalyst by two distinct methods and its application in liquid phase oxidation reactions. The materials were characterized by various spectral techniques and their catalytic potential has been investigated for the oxidation of cyclohexene. The influences of various reaction parameters have also been studied. Under optimum reaction conditions excellent to higher yield of epoxide (91%) was obtained by Mo-VPO* prepared by impregnation method. The promoting effect of Mo on VPO solids was found to be a function of the way the ion was added during the preparation of the VOHPO4·0.5H2O phase. XPS analysis of the catalysts showed the presence of couple V4+/V5+ on the surface of Mo-VPO which facilitates the reaction. The catalyst showed its recapability more than four times without any appreciable change in conversion and selectivity. The synergetic effect between Mo and V, to the contrary, made the active phase, VPO, more stable.

Excellent to higher yields of epoxide were obtained from cyclohexene over Mo-VPO catalyst using TBHP as oxidant. The presence of couple V4+/V5+ on the surface of Mo-VPO facilitates the reaction.Figure optionsDownload high-quality image (125 K)Download as PowerPoint slide