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.