Green Synthesis of Tetrahydrofuran Aminoalcohols From HMF and Ammonia in Aqueous Phase: Boosting Activity and Stability Using Non‐noble Bimetallic Carbon Encapsulated NiCo Alloy Catalyst

The synthesis of the 5‐hydroxymethyl‐2‐tetrahydrofurfuryl amine (THMFA) by the reductive amination of 5‐Hydroxymethylfurfural (HMF) with ammonia through a single reaction step has been studied in aqueous phase using monodispersed Ni and Co nanoparticles encapsulated in a thin carbon layer. The Ni@C and Co@C catalysts were prepared starting from the corresponding oxides and using glucose a carbon source following a hydrothermal method. While the Co@C catalyst showed low selectivity to the target THMFA due to the formation of byproducts coming from the over‐hydrogenation of HMF, Ni@C catalyst resulted in much more selective, however, it showed poor stability. The catalyst instability was solved by preparing a bimetallic NiCo alloy sample (Ni 1 Co 1 @C molar ratio Ni/Co 1:1) which not only resulted more active than Ni, but it was stable and reusable upon several reaction cycles, maintaining activity and selectivity. The high selectivity of THMFA obtained when using water as reaction media (95%), compared with the obtained when tetrahydrofuran is used as a solvent (51%) suggest that water plays a key role on selectivity, inhibiting the accumulation of the secondary imine intermediate by accelerating the transimination process between de secondary imine and ammonia.