Nickel and nickel–platinum as active and selective catalyst for the maleic anhydride hydrogenation to succinic anhydride

Pt, Ni, Co, Cu and bimetallic Pt–Ni, Pt–Co, Pt–Cu catalysts supported on γ-Al2O3 have been studied for the hydrogenation maleic anhydride (MA) to succinic anhydride (SA). X-ray diffraction (XRD) and H2 temperature programmed reduction TPR studies were performed to characterize the catalysts. The flow reactor studies demonstrated that Pt–Ni bimetallic catalyst is highly active and selective for the hydrogenation of MA. Hydrogenation of maleic anhydride produced mainly succinic anhydride and γ-butyrolactone, and the selectivity toward γ-butyrolactone increased with pressure. Using Al2O3 as support, it was possible to obtain the highest reaction rate ever obtained with 90% selectivity to SA at 100% conversion. The process appears to be controlled by H2 dissociation on nickel and the catalytic activity can be further improved, without loss of selectivity, by adding a very small amount of Pt(0.3) to increase the rate of H2 dissociation.TPR experiments show high-temperature reduction peaks in monometallic Ni catalysts. When Pt is present, the formation of Pt–Ni compound provokes the shift of the reduction peaks and the appearance of new reduction signals.

► The supported PtNi bimetallic catalysts exhibited the highest activity. ► A small amount of Pt further improves the activity and selectivity of Ni/Al2O3. ► The formation of Pt–Ni compound provokes the shift of the reduction peaks.