Continuous Transfer Hydrogenolysis of Diphenyl Ether Using 2-Propanol and Ni Catalyst-Fixed Bed Reactor

Continuous liquid-phase transfer hydrogenolysis of diphenyl ether (DPE), a lignin model compound, was carried out utilizing 2-propanol (IPA) as a hydrogen-donating solvent and a Ni catalyst-fixed bed reactor. Approximately 90% conversion of DPE and the corresponding formation of monomeric products (benzene, phenol, cyclohexane, and cyclohexanol) were observed without short-term catalyst deactivation under the following conditions: 160 °C, 0.10 M DPE in IPA, 4.4 min average catalyst contact time, and 6.0 MPa system pressure. Further analysis showed that the continuous reaction system was capable of suppressing undesired subreactions such as H2 gas formation and phenol hydrogenation, while catalyst regeneration was also possible under certain conditions.