Catalytic activities of niobium oxide for the liquid-phase hydrogenation of maleic anhydride and hydration of succinonitrile

Co and Pd supported on Nb₂O₅ catalyst was active for the hydrogenation of maleic anhydride to γ-butyrolactone and tetrahydrofuran in the liquid-phase. The catalyst was more active than Co and Pd supported on diatomaceous earth, SiO₂ and Al₂O₃. Co and Pd seem to be stable on Nb₂O₅.

Nb₂O₅ · nH₂O was active for the hydration of succinonitrile to β-cyanopropionamide, that is an intermediate for -pyrrolidone, in the liquid-phase. Niobium oxide showed unique catalytic activities, especially, in the presence of water.