Photoinduced metathesis reaction of C3H6 on supported MoO3 catalyst

Abstract

Ultraviolet irradiation of MoO3 supported on porous Vycor glass (PVG) in the presence of C3H6 has been found to induce the formation of approximately equimolar amounts of C2H4 and 2-C4H8 as well as a small amount of CH3CHO, suggesting that the metathesis reaction of C3H6 occurs. The dependence of the yields upon the excitation wavelength is in good agreement with the excitation band of the phosphorescence of MoO3/PVG, which arises from the charge-transfer transition (Mo6+O2–) [graphic omitted] (Mo5+—O–).* The quenching of the phosphorescence of MoO3/PVG and the decrease in the yield of C3H6 metathesis on adding O2 and CO suggest that the photoinduced metathesis reaction is closely associated with the charge-transfer excited triplet state of MoO3/PVG. From these results, together with those of e.s.r. experiments reported previously, the mechanism of the photoinduced C3H6 metathesis, especially the primary process of metal–carbene formation, is discussed.