The Direct Ethanol Conversion to Hydrocarbons over Pt- Containing Catalysts

Here, we present ethanol transformation into hydrocarbons C4-C12 through a one-step catalytic process. A number of industrial Pt-containing catalysts samples (AP-64, R-254, IP-62, Pt-Re/Al2O3) were used, as well as an original Pt-Sn/Al2O3 catalyst. All the catalytic experiments were carried out at 5 atm and 350 °C. After a pretreatment procedure under 50 atm of H2 at 450 °C during 12 hours, the catalysts improved a enhanced selectivity to hydrocarbons. After about 10 hours on stream, catalytic activity decreased due to coking issues. However, high catalytic performance could be recovered after calcination in air followed by reduction at 450 °C. In general, the hydrocarbons C4-C12 yield varied from 20 to 50 wt.% over the different catalysts samples. Depending on the support nature, the ethanol was preferentially converted to alkanes or olefins. The effect of metal addition to Pt-containing catalysts was studied on some industrial Pt-Re and one original Pt-Sn samples. Re addition led to high activity for the formation of olefins, of which the yield reached up to 40 wt.%. Sn addition promoted both olefins and oxygenates formation. The most suitable catalyst for obtaining fuel hydrocarbons (gasoline compounds) was found to be the platinum/alumina catalyst AP-64. The structural particularities of this sample were studied using the XAS technique. Relations between the Pt clusters structure and the catalytic properties were identified.