Ethylene and Acetaldehyde Production by Selective Oxidation of Ethanol Using Mesoporous V-MCM-41 Catalysts

Vanadium-incorporated MCM-41 type catalytic materials, which were synthesized by a direct hydrothermal synthesis procedure, showed very high activity and high selectivity in the production of ethylene from ethanol in an oxidative process. Ethylene selectivity showed a significant increase with an increase in temperature over 300 °C, while relatively high acetaldehyde selectivities were observed at lower temperatures. An ethylene yield value of 0.66 obtained at 400 °C with an O2/ethanol feed ratio of 0.5 was beneficial from the point of view that these results might open a new pathway for the production of ethylene from a nonpetroleum environmentally friendly feedstock, namely, bioethanol. The optimum V/Si ratio of the catalyst, which gave the maximum ethylene yield, was found to be around 0.04. Experimental results showing the formation of acetaldehyde and not showing the formation of ethylene in the absence of gasphase oxygen and the catalyst deactivation observed in such conditions suggested a redox mechanism involving the surface lattice oxygen of the catalyst in acetaldehyde production, while the involvement of adsorbed oxygen was concluded to take place in the formation of ethylene.