Catalytic transfer hydrogenolysis mechanism of benzyl phenyl ether over NiCu/Al2O3 using isopropanol as hydrogen source

Efficient transfer hydrogenolysis of benzyl phenyl ether (BPE) was accomplished over Ni1.5Cu1.5/Al2O3 using isopropanol as hydrogen source. The characterization results demonstrated that the formation of NiCu alloy and electron transfer between Ni and Cu were responsible for the excellent catalytic performance. Isopropanol displayed better hydrogen-donating ability than other low-carbon alcohols because of its unique dehydrogenation pathway and small steric hindrance. The results of isotopic experiments elucidated that active hydrogen species for the C-O bond cleavage originated from isopropanol rather than H2, while both isopropanol and H2 were responsible for hydrogenation of phenol to cyclohexanol when reaction was conducted with mixed hydrogen sources. A mechanism study illustrated that transfer hydrogenolysis of BPE proceeded through direct cleavage of C-O bond followed by phenol hydrogenation, in which the active hydrogen species were in the form of H+ and H  .

Automated summary

Efficient transfer hydrogenolysis of benzyl phenyl ether was achieved using Ni1.5Cu1.5/Al2O3 catalyst with isopropanol as hydrogen source. The formation of NiCu alloy and electron transfer between Ni and Cu were found to be responsible for the excellent catalytic performance. Isopropanol demonstrated better hydrogen-donating ability than other low-carbon alcohols due to its unique dehydrogenation pathway and small steric hindrance. The active hydrogen species for the C-O bond cleavage originated from isopropanol, while both isopropanol and H2 were involved in the hydrogenation of phenol to cyclohexanol.