Boosted nitrilation of dimethyl adipate with NH₃ to adiponitrile over bimetallic oxide: Synergetic effect between Nb and W

To reach highly active and selective gas-phase nitrilation of dimethyl adipate (DMA) with NH₃, a series of Nb_xW_10-x (x = 10, 9, 7, 5 and 0) composite were fabricated by a sol–gel method to approach the homogeneous combination of NbO_x and WO_x. As a result, the single-pass yield of adiponitrile (ADN) reached 85.2% over Nb₉W₁ under lower reaction temperature and lower NH₃/DMA molar ratio. Consequently, the space–time yield (STY) of ADN over Nb₉W₁ was 1.7 ∼ 30 times higher than that of previous catalysts. Mechanistic experiments demonstrated the activity strongly correlates the interaction between the carbonyl functionality and the composite. Further, a significant synergistic effect between W and Nb was disclosed, wherein the Nb-based domains account for activating DMA while the W-based domains mainly adsorb and activate NH₃ feedstock.