Selective Conversion of HMF into 3-Hydroxymethylcyclopentylamine through a One-Pot Cascade Process in Aqueous Phase over Bimetallic NiCo Nanoparticles as Catalyst

Abstract

5-hydroxymethylfurfural (HMF) has been successfully valorized into 3-hydroxymethylcyclopentylamine through a one-pot cascade process in aqueous phase by coupling the hydrogenative ring-rearrangement of HMF into 3-hydroxymethylcyclopentanone (HCPN) with a subsequent reductive amination with ammonia. Mono- (Ni@C, Co@C) and bimetallic (NiCo@C) nanoparticles with different Ni/Co ratios partially covered by a thin carbon layer were prepared and characterized. Results showed that a NiCo catalyst, (molar ratio Ni/Co=1, Ni_0.5 Co_0.5 @C), displayed excellent performance in the hydrogenative ring-rearrangement of HMF into HCPN (>90 % yield). The high selectivity of the catalyst was attributed to the formation of NiCo alloy structures as hydrogenating sites that limited competitive reactions such as the hydrogenation of furan ring and the over-reduction of the formed HPCN. The subsequent reductive amination of HPCN with aqueous ammonia was performed giving the target cyclopentylaminoalcohol in 97 % yield. Moreover, the catalyst exhibited high stability maintaining its activity and selectivity for repeated reaction cycles.

Keywords: 5-hydroxymethylfurfural; biomass; heterogeneous catalysis; hydrogenative ring-rearrangement; reductive amination.