Selective oxidation of biomass-derived carbohydrate monomers

Abstract

Current efforts in the decarbonisation and electrification of the chemical industry drive the interest in green production processes. We looked at the potential production processes for glucaric acid, which was recognized as one of the “highest value-added biomass-derived chemicals” by the US Department of Energy in 2004. Glucaric acid is a very interesting and important base chemical that can be converted into numerous end products, ranging from pharmaceuticals to bio-based polymers. Widespread use of glucaric acid would drastically reduce the carbon dioxide emissions and enable the renewable production of polymers, e.g. nylon 66. The current industrial nitric acid oxidation of glucose pushed the research towards the development of more sustainable oxidation practices, which can be classified into four broad categories: biocatalysis, heterogeneous catalysis, electrocatalysis, and photocatalysis. Since each approach requires a unique experimental setup, the comparison among them is often tedious. Enzymes require milder temperatures and pressures and provide high selectivity, but are fragile and thus unstable, compared with metallic catalysts, where selectivity is lower but productivity is usually higher. Electro- and photocatalytic processes are relatively new and promising techniques for glucose oxidation, harnessing electric potential and the power of photons, but currently suffer from low space-time yield. Furthermore, we used space-time yield as a robust comparison parameter, even though it is not as universal as, say, techno-economic analysis, which is almost impossible at this scale, due to the lack of data provided by each study. Therefore, we briefly review each approach, analyse the state of the art, and provide general guidelines for future research.