Sustainable Productions of Organic Acids and Their Derivatives from Biomass via Selective Oxidative Cleavage of C-C Bond

Biomass is renewable and the most abundant carbon resource, and it shows great potential for sustainable production of chemicals in the future. With respect to limited fossil reserves, biomass conversion has aroused global attention. The use of biomass as a resource has developed rapidly in recent years, and various kinds of chemicals could be produced from biomass. Although biomass is annually renewable and abundant, it is important to process it in the most efficient way. Before rushing into biomass conversion, it is necessary to consider what chemicals are reasonably and economically produced from biomass. In this Review, we first analyzed the products from biomass based on the structural properties and economics. Taking into account the oxygen-rich character of the feedstock, it is a reasonable route to convert the biomass into valuable oxygen-containing fine chemicals, among which organic acids are one class of important and widely used fine chemicals. Then, we provided insights into the recent progress in the oxidative cleavage of biomass into organic acids and their derivatives, such as esters and anhydrides. The biomass resources cover the lignocellulose biomass, sugars, chitin, platform molecules, and fats. As biomass resources are generally polymers and the C-C bond is the backbone, the oxidative cleavage of C-C bond can break up the biomass to small molecules and introduce acid functionality at the same time. This Review particularly focuses on the generation of acids via a C-C bond-oxidative-cleavage process. Various methods, catalytic systems, and C-C bond-cleavage mechanisms are summarized. Finally, we conclude with mentioning the challenges in the oxidative conversion of biomass and the possible research direction in this area.