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. RhO x present in Vulcan XC72supported 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 Rh 5 /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 H 2 pressure of 1000 psi and 60 °C for 3.5 h.

A functional greener solvent mixture containing water, isopropyl alcohol (IPA) and ethyl acetate with the ratio 10:20:70 (wt%) was found to accelerate hydrogenation of bisphenol A type epoxy resin BE503 with a molecular weight of 1500 through an on-water mechanism, and led to an increased H2 availability, due to high solubility of H2 in IPA. Different carbon-based supports were tested and VulcanXC72 was found as the best support among the tested carbon-based ones as it possessed the highest amount of electron deficient promoter, RhOx. The catalyst, Rh5/VulcanXC72-polyol, synthesized by the microwave assisted polyol method, yielded a 100% hydrogenation of aromatic rings with an epoxy ring opening below 20.0% at 50 °C and a H2 pressure of 1000 psi in 2.25 h. Intrinsic activation energies for the hydrogenation of aromatic rings and epoxy ring opening were experimentally estimated and a mechanism for the hydrogenation of BE503 was proposed, wherein the hydrogenation of aromatic rings and epoxy ring opening in BE503 proceeded simultaneously in parallel and in-series with parallel being the major pathway.