Hydrogenation Of Maleic Anhydride Succinic Anhydride Catalysts

In this paper, PtNi bimetallic and Ni monometallic catalysts supported on HY-Al2O3,HX-Al2O3,ZSM-5-Al2O3,USY-A12O3,Beta-A12O3 and A12O3 were prepared and evaluated for the hydrogenation of maleic anhydride in the temperature range of 40-260℃. The catalysts, which contained 3-30 wt % Ni, were prepared via a kneading and impregnation method. The catalysts were characterized by an array of techniques, including X-ray diffraction (XRD) and H2 temperature-programmed reduction (TPR). The nature of the Ni species on the support, and their interaction with the support, were studied. XRD and TPR studies showed that nickel was present as Ni2+ and Ni3+ species on the support, and that there was no elemental nickel (Ni0) in the unreduced samples. Pretreatment using pure H2 at different temperatures affected the reactivity. Pretreatment at 350℃for 3 h was the best among the conditions tested. XRD and TPR studies showed that Ni was present as Ni2+ (NiO, NiAl2O4) and Ni3+(Ni2O3) on the support, and that there was no Ni0 in the unreduced samples. The calcination temperature and Ni loading have a significant effect on catalyst structure and activity. For the impregnation catalyst, the activity Ni content increased with decreasing the calcination temperature. For the kneading catalyst, higher calcination temperature decreases their activities. The hydrogenation of MA showed that the catalyst calcined at 550℃gave the best results. Results from flow reactor studies showed that supports strongly affected the catalytic properties of different bimetallic and monometallic catalysts. The results showed that the HY-Al2O3 support exhibited the highest activity and selectivity. Using NiPt/Al2O3-HY catalyst and performing the reaction, it was possible to carry out the lowest reaction temperature (40℃) ever carried at 100% conversion. Adding a small amount of Pt (0.5) to the Ni (5%)/Al2O3-HY catalyst that is effective for increasing the selectivity and activity. The conversion of maleic anhydride (100%) and selectivity to succinic anhydride (95%) were obtained over Ni (5%)/Al2O3-HY at a reaction temperature 190℃and WHSV of 2h-1 under 0.8 MPa pressure.