Recent Catalytic Advances on the Sustainable Production of Primary Furanic Amines from the One-Pot Reductive Amination of 5-Hydroxymethylfurfural

5-Hydroxymethylfurfural (5-HMF) represents a well-known class of lignocellulosic biomass-derived platform molecules. With the presence of many reactive functional groups in the structure, this versatile building block could be valorized into many value-added products. Among well-established catalytic transformations in biorefinery, the reductive amination is of particular interest to provide valuable N-containing compounds. Specifically, the reductive amination of 5-HMF with ammonia (NH₃ ) and molecular hydrogen (H₂ ) offers a straightforward and sustainable access to primary furanic amines [i. e., 5-hydroxymethyl-2-furfuryl amine (HMFA) and 2,5-bis(aminomethyl)furan (BAMF)], which display far-reaching utilities in pharmaceutical, chemical, and polymer industries. In the presence of heterogeneous catalysts contanining monometals (Ni, Co, Ru, Pd, Pt, and Rh) or bimetals (Ni-Cu and Ni-Mn), this elegant pathway enables a high-yielding and chemoselective production of HMFA/BAMF compared to other synthetic routes. This Review aims to present an up-to-date highlight on the supported metal-catalyzed reductive amination of 5-HMF with elaborate studies on the role of metal, solid support, and reaction parameters. Besides, the recyclability/adaptability of catalysts as well as the reaction mechanism are also provided to give valuable insights into this potential 5-HMF valorization strategy.

Sustainable Catalytic Transformation of Biomass-Derived 5-Hydroxymethylfurfural to 2,5-Bis(hydroxymethyl)tetrahydrofuran

5-Hydroxymethylfurfural (5-HMF), one of the most important platform molecules in biorefinery, can be directly obtained from a vast diversity of biomass materials. Owing to the reactive functional groups (-CHO and -CH₂ OH) in the structure, this versatile building block undertakes several transformations to provide a wealth of high value-added products. Among numerous well-established paradigms, the catalytic hydrogenation of 5-HMF towards 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) is of great interest because this downstream diol can be exploited in a wide range of industrial applications. Not surprisingly, incessant endeavors from both academia and industry to upgrade this catalytic process have been established over the years. The main aim of this Review was to provide a comprehensive overview on the development of heterogeneous metal catalysts for the 5-HMF-to-BHMTHF transformation. Herein, the rational design and utility of hydrogenating catalysts were elaborated in many aspects including metal types (Ni, Co, Pd, Ru, Pt, and bimetals), solid supports, preparation method, recyclability, operating conditions, and reaction regime (batch and continuous flow). In addition, the assessment of cooperative catalysts to convert carbohydrates into BHMTHF under one-pot cascade, tentative mechanism, as well as prospects and challenges for the chemo-selective hydrogenation of 5-HMF were also highlighted.