Highly efficient catalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid using bimetallic Pt-Cu alloy nanoparticles as catalysts

Catalytic conversion of cellulosic biomass to harvest high-valued organic acids

Catalytic conversion of biomass provides an alternative way for the production of organic acids from renewable feedstocks. The emerging process contains complex reactions and strategies to cut down those complex biogenic materials into target molecules. Here, we review the catalytic conversion of cellulosic biomass toward high-valued organic acids. This work has summarized the key controlling reactions which lead toward formic acid, glycolic acid, or sugar acids in oxidative conditions and the main pathways for lactic acid or levulinic acid in the anaerobic environment from cellulosic biomass and its derivatives. We evaluate and compare different strategies and methods such as one-pot and two-step conversion. Additionally, the optimization of catalytic reactions has been discussed to realize the design of C-C coupling reactions, the development of multifunctional materials, and new efficient system. In all, this article gives an insight guide to precisely convert cellulosic biomass into target organic acids.

5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid on Noble Metal-Free Nanocrystalline Mixed Oxide Catalysts

Noble metal-free catalysts based on earth-abundant and inexpensive mixed oxides are active catalysts of all steps of the reaction cascade leading from 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using tert-butyl hydroperoxide (TBHP) as oxidation agent. Catalysts covering the whole range of composition in the Cu-Mn and Co-Fe series have been prepared and characterised. The nature and composition of the catalyst strongly affect conversion and selectivity. The distribution of products indicates that radical-type oxygen species, deriving from the activation of TBHP, play a determining role in the reaction. The early steps of reaction mainly follow the pattern expected for heterogeneous Fenton catalysts. Mixed oxide catalysts are the most effective in further oxidation steps, leading to the formation of FDCA, both in the Cu-Mn and Co-Fe systems. This behaviour can be related to the distribution of charge in the mixed oxides, suggesting a possible implication of the lattice oxygen in the last reaction steps. The results provide indications on how to optimize the reaction and minimize the formation of byproducts (humins and oligomers).

Research Progress of Highly Efficient Noble Metal Catalysts for the Oxidation of 5-Hydroxymethylfurfural

5-hydroxymethylfurfural (HMF) is considered to be one of the most pivotal multifunctional biomass platform chemicals. This Review discusses recent advances in catalytic oxidation of HMF towards high-value products. The reaction mechanism of different noble metals and the path of HMF oxidation to high-value products have been deeply investigated in the noble metal catalytic system. The reaction mechanisms of different noble metals and HMF conversion paths were compared in detail. Moreover, the factors affecting the performance of different noble metal catalysts were summarized. Finally, effective strategies were put forward to improve the catalytic performance of noble metal catalysts. The purpose is to provide a valuable reference for the academic research on the preparation of oxidation products from biomass-based HMF and the industrial application of noble metal catalysts.