Hydrogenation of Bisphenol A-Type Epoxy Resin (BE186) over Vulcan XC72-Supported Rh and Rh-Pt Catalysts in Ethyl Acetate-Containing Water

Abstract

This study demonstrates the hydrogenation of a bisphenol A-type epoxy resin (BE186) through solvent selection, development of a catalyst for aromatic ring hydrogenation, and control of epoxy loss. A functional greener solvent, water in ethyl acetate, was proposed based on solvatochromic parameters, high α and low β. RhOx present in Vulcan XC72-supported monometallic Rh and bimetallic Rh-Pt catalysts prepared by the polyol method acted as a promoter for hydrogenation. The hydrogenation pathway to control epoxy loss was proposed through changes of the reactant to the catalyst ratio and temperature. Though Rh-Pt catalysts were superior to Rh for aromatic ring hydrogenation, they led to higher epoxy loss owing to excessive C-O bond cleavage. Using Rh5/Vulcan XC72-polyol, 3 wt % water in ethyl acetate, and a reactant to catalyst ratio of 100:1, complete hydrogenation of BE186 with 3.4% epoxy loss was achieved at a H2 pressure of 1000 psi and 60 °C for 3.5 h.