Platform chemicals, derived from cellulose

Recent attempts aim at the controlled transformation of cellulose, hemicellulose, and lignin to platform molecules for a potential future biorefinery scenario. In this regard, the U.S. Department of Energy has published studies on potential future platform molecules that could be derived from renewable resources [35, 36]. Tailored transformation of biomass to these platform chemicals could serve as a starting point for biofuel production. This would allow the development of comprehensive biorefinery approaches that incorporate both the production of biofuels and chemicals. The... 

Cellulosic and hemicellulosic feedstocks may be converted into 100+ chemicals, among them drop-in products but also several novel chemicals. Aside from biofuels and their precursors, they may be classified as end products, platform chemicals, monomers, and chemical intermediates (leading to a specific end-product). Some of these are already produced commercially from carbohydrates whereas others are currently petroleum or natural gas derived. Most of the chemicals described here are not produced commercially to date. 

The next two sections of this review chapter will introduce the reader to the world of lactic acid. The acid is both a key platform chemical of the biorefinery concept, from which other interesting molecules may be formed (Sect. 2), and a monomer for commercial bioplastic polylactic acid (PLA) (Sect. 3). In the platform approach, the assessment from Chap. 1 in this volume [23] proves its value, as it is an equally useful tool to seek out the most desired routes for transforming a biomass-derived platform molecule as it is to select the most relevant carbohydrate-based chemicals from a chemist s point of view. In what follows, the desired catalytic cascade from cellulose to lactic acid will be described (Sect. 4) as well as the specific catalytic data reported for different feedstock (Sects. 5 and 6). Section 7 will introduce the reader to recent synthesis routes for other useful AHA compounds such as furyl and vinyl glycolic acid, as well as others shown in Fig. 1. Before concluding this chapter, Sect. 8 will provide a note on the stereochemistry of the chemically produced AHAs. 

Wood chips can also be utilized as such to produce bioethanol. The cellulose and hemicellulose material is hydrolyzed in the presence of acids (H2SO4, HCl, or HCOOH) or enzymes to yield glucose and other monosaccharides [16]. Lignin is separated by filtration as a solid residue and the monosaccharides are fermented to ethanol, which, in turn, is separated from water and catalyst by distillation. Ethanol can be used not only as energy source but also as a platform component to make various chemicals, such as ethene and polyethene. Today green acetaldehyde and acetic acid from wood-derived bioethanol is manufactured by SEKAB Ab, at the Ornskoldsvik Biorefinery of the Future industrial park. 

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