Hydrogenation of High Molecular Weight Bisphenol A Type Epoxy Resin BE503 in a Functional and Greener Solvent Mixture Using a Rh Catalyst Supported on Carbon Black

Abstract

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.

Production of Environmentally Friendly Polyester by Hydrogenation of Poly(butylene terephthalate) over Rh–Pt Catalysts Supported on Carbon Black and Recovery by a Compressed CO2 Antisolvent Technique

“…52,53 A similar advantage of RhO x and emergence of RhO x due to the polyol synthesis method was observed by us in previous studies for the hydrogenation of BPA-type epoxy resins, BE186 and BE503, as well as for the hydrogenation of poly(ethylene terephthalate) (PET) also using VulcanXC72-supported Rh and Rh−Pt catalysts synthesized using the polyol method. 28,48,52 At the same time, the lower conversions were observed for Rh 5 / VulcanXC72 (WI) and Rh 5 /VulcanXC72 (CFD) that were devoid of RhO x , once again validating its part as a promoter in this reaction. The presence of RhO x coupled with the fact that the metal NPs in Rh 5 /VulcanXC72 (polyol) were located on the external surface of VulcanXC72 led to the conclusion that the polyol method was superior to WI or CFD for the hydrogenation of PBT to PBC.…”

“…For Rh and Rh–Pt/VulcanXC72 (polyol), the average particle size lies in between 2 and 4 nm. From the TEM images of the polyol-synthesized catalysts, it was confirmed that the Rh and Rh–Pt NPs were located majorly on the external surface of VulcanXC72 . Eguizabal et al also reported that for WI of Pt NPs on VulcanXC72, Pt NPs were deposited on the external surface of VulcanXC72 rather than inside its pores.…”

“…From the TEM images of the polyol-synthesized catalysts, it was confirmed that the Rh and Rh−Pt NPs were located majorly on the external surface of VulcanXC72. 48 Eguizabal et al 49 also reported that for WI of Pt NPs on VulcanXC72, Pt NPs were deposited on the external surface of VulcanXC72 rather than inside its pores. The rapid polyol method was therefore thought to not have provided enough time to precipitate metal NPs inside the pores of the catalyst.…”

“…The reaction for the hydrogenation of PBT to PBC could be said to be first order and was also confirmed from our previous study for the hydrogenation of BE503. 48 The measured rate constants for the hydrogenation of BE503 by assuming a pseudo-first-order reaction devoid of For the HFIP + H 2 system, the gas solubility of H 2 in HFIP is expected to increase at increasing pressures, thereby enabling more H 2 to be available for dissociation to H atoms in the liquid phase, similar to what was experimentally observed for the solubility of H 2 in methanol in a similar H 2 pressure range during the hydrogenation of p-chloronitrobenzene. 55 The observed results are shown in Table 4, wherein a directly proportional relationship was found between the conversion and H 2 pressure.…”

Structural Adhesives Tapes Based on a Solid Epoxy Resin and Multifunctional Acrylic Telomers

“…The field of application of epoxy resins (ERs) as structural binders and polymer matrices is constantly expanding [ 1 , 2 , 3 , 4 ]. Adhesives based on ERs are classified as reactive systems and show excellent properties, especially when joining ceramics and metals [ 5 , 6 , 7 ].…”