INFLUENCE OF MO-DOPING ON VPO CATALYST FOR PARTIAL OXIDATION OF ETHANE

Six MoVPO catalysts were prepared with Mo/V ratios of 0.0, 0.05, 0.1, 0.2, 0.3, 0.5 and P/V of 1.15 for all catalysts,using an isobutanol – benzylalcohol solvent. Molybdenum was introduced to the VPO catalyst by impregnation. XRD, ICP, BET and SEM were used for the catalyst characterization. A maximum acetic acid yield of 1.1 % was obtained using contact time of 3.6 Sec. at 573 K and 1360 kPa using VPO catalyst with Mo/V ratio of 0.2 calcined at 723 K under nitrogen flow. At these conditions the ethane conversion was 2.8% and acetic acid and ethylene selectivities were about equal at 37%. Mo has the effect of decreasing the ethane conversion and increasing acetic acid selectivity with the initial increase of Mo/V ratio then the selectivity drop to zero at Mo/V = 0.5. It was found that exposing the catalyst to a reactant mixture lean in ethane at elvated temperature overnight before starting the reaction ,resulted in an increase in acetic acid selectivity.