Ultrauniform Ru Nanoclusters as Efficient Hydrogenation Catalysts for Phthalates

Cyclohexane dicarboxylic acid (CHDA) ester, a kind of environmental-friendly plasticizer, can be produced by phthalates hydrogenation. However, the synthesis of catalysts with high activity and selectivity is a challenge due to the stability of aromatic rings. In this work, a series of ultrauniform Ru nanoclusters supported by γ-Al2O3 are synthesized for the hydrogenation of diisononyl phthalate (DINP). Results show that the conversion of DINP and the selectivity of diisononyl-cyclohexane-1,2-dicarboxylate (DINCH) both reach 100% at 140 °C and 3 MPa H2 pressure. Diisononyl-cyclohexene-1,2-dicarboxylate (4H-DINP) and 1,2-cyclohexanedicarboxylate-7-methyloctyl ester are found; the hydrogenation reaction network of DINP is constructed. Alkali metal ions adsorbed on the surface of Ru nanoclusters prepared by the polyol method can stabilize Ru3+-Hδ− species by electrostatic interaction, thus affecting the hydrogenation activity of the catalyst, following the order of Li+ > Na+ > K+ > Cs+. Ru-based catalysts prepared by the polyol method have good prospects for application in phthalates hydrogenation.