NiO-MnO2/Nb2O5-TiO2 catalyzed reaction integration of butanal self-condensation and successive hydrogenation and its kinetics

BACKGROUND The reaction integration of butanal self-condensation and successive hydrogenation (that is, one-step synthesis of 2-ethylhexanol from butanal) is an efficiency way to simply process flow and reduce energy consumption for the commercial manufacture of 2-ethylhexanol (2EHO). In the present work, a NiO-MnO 2 /Nb 2 O 5 -TiO 2 catalyst was prepared for the integration reaction to reach a high 2-ethylhexanol selectivity. Furthermore, the reaction integration was investigated kinetically for the next scale-up. RESULTS A 2EHO selectivity of 90.0% was achieved at a complete conversion of butanal with the help of reduction-in-reaction technique in this reaction integration. The reaction rate of butanal is determined by the reversible aldol self-condensation reaction and its direct hydrogenation reaction. The reaction order with respect to butanal in the two reactions is, respectively, 2.004 and 1.004. The activation energy of the hydrogenation reaction is higher than that of the forward reaction of the self-condensation, suggesting the suppressive effect the reaction integration on the direct hydrogenation. CONCLUSION The reaction integration promotes butanal self-condensation and successive hydrogenation and it suppresses butanal direct hydrogenation by using NiO-MnO 2 /Nb 2 O 5 -TiO 2 catalyst with the help of reduction-in-reaction technique, giving rise to a pretty high selectivity of 2-ethylhexanol. The establishment of the integration reaction kinetics will lay the foundation for reactor design and analysis. © 2021 Society of Chemical Industry