Lignin depolymerization is one of the most significant barriers to reaching the full potential of lignocellulosic biofuels as fossil fuel replacements. The problem stems from the fact that lignin comprises 15−25% of the mass found in lignocellulose and up to 40% of the energy content. For lignocellulosic biofuels to be sustainable, chemistry must be developed to convert lignin into small molecules that can be upgraded into a fuel stream. Homogeneous and heterogeneous catalytic processes for both oxidative and reductive lignin depolymerizations are known. We are currently developing a tandem catalytic dehydrogenation/C−O bond cleavage that enables a redox neutral approach for lignin depolymerization. This approach is noteworthy both as a novel C−O bond-cleavage reaction and as a process for depolymerization that requires no added reagent.
Read More: Jason Nichols, Lee Bishop, Robert Bergman, and Jonathan Ellman, Catalytic C-O Bond Cleavage of 2-Aryloxy-1-arylethanols and its Application to the Depolymerization of Lignin Related Polymers, Journal of the American Chemical Society, 2010, 132, 12554.
New catalysts to promote the transformation of biobased materials are of great interest. There are a number of renewable feedstock based chemicals that are coming onto the market, and the large scale use of these chemicals will depend on the development of new catalysts and processes to turn these chemicals into valuable products.
Valorization of Ethylene Glycol: Elena Arceo, Jonathan Ellman, and Robert Bergman, Rhenium-Catalyzed Didehydroxylation of Vicinal Diols to Alkenes Using a Simple Alcohol as a Reducing Agent, Journal of the American Chemical Society, 2010, 132, 11408.
100% Bio-PET: Shiramizu, M. and Toste, F. D. , On the Diels–Alder Approach to Solely Biomass-Derived Polyethylene Terephthalate (PET): Conversion of 2,5-Dimethylfuran and Acrolein into p-Xylene. Chemistry - A European Journal, 2011, 17, 12452, doi: 10.1002/chem.201101580
Biomass-Based Benzoic Acid: Arceo, E.; Ellman, J.A.; Bergman, R.G. "A Direct, Biomassed-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid" ChemSusChem. 2010, 3, 811-813.