Page 4 of 5
Peter J. Deuss, Katalin Barta and Johannes G. de Vries
The transition from a petroleum-based infrastructure to an industry which utilises renewable resources is one of the key research challenges of the coming years. Biomass, consisting of inedible plant material that does not compete with our food production, is a suitable renewable feedstock. In recent years, much research has been focused on developing new chemical strategies for the valorisation of different biomass components. In addition to the many heterogeneous and enzymatic approaches, homogenous catalysis has emerged as an important tool for the highly selective transformation of biomass, or biomass derived platform chemicals. This Perspective provides an overview of the most important recent developments in homogeneous catalysis towards the production and transformation of biomass and biomass related model compounds. The chemical valorisation of the main components of lignocellulosic biomass â€“ lignin and (hemi)cellulose is reviewed. In addition, important new catalyst systems for the conversion of triglycerides and fatty acids are presented.
Isolation of Functionalized Phenolic Monomers through Selective Oxidation and C-O Bond Cleavage of the Î²-O-4 Linkages in Lignin
Christopher S. Lancefield, Dr. O. Stephen Ojo, Dr. Fanny Tran and Prof. Nicholas J. Westwood
Functionalized phenolic monomers have been generated and isolated from an organosolv lignin through a two-step depolymerization process. Chemoselective catalytic oxidation of Î²-O-4 linkages promoted by the DDQ/tBuONO/O2 system was achieved in model compounds, including polymeric models and in real lignin. The oxidized Î²-O-4 linkages were then cleaved on reaction with zinc. Compared to many existing methods, this protocol, which can be achieved in one pot, is highly selective, giving rise to a simple mixture of products that can be readily purified to give pure compounds. The functionality present in these products makes them potentially valuable building blocks.
Saumya Dabral, Jakob Mottweiler, Torsten Rinescha and Carsten Bolm
A base-catalysed transformation and cleavage of lignin Î²-O-4 model compounds in dimethyl carbonate is reported. The reaction system consists of readily available bases and inexpensive dimethyl carbonate as a solvent and reagent, affording methoxy benzene or 2-aryloxyvinyl benzene derivatives in good to very good yields. The applicability of the system for the bond cleavage in an organosolv lignin sample was demonstrated.