Lignin, Cellulose Hemicellulose and Wood Valorisation
More and more is the demand for valorisation of lignin. As the industry focus in Finland starts to shift from utilisation of Finnish biomass for production of the higher-value pulp to the lower-value biofuels, valorisation of lignin becomes more and more important, form technoeconomical standpoint. New methods for conversion of lignin, a highly complex heteropolymer, into materials, chemicals and energy are required. New methods for this purpose are under development at our University of Helsinki laboratory but are not public at present.
One recent article we published (DOI: 10.1002/cssc.201402794) concerns the upgrading of cellulose with dimethylcarbonate (DMC). DMC is low toxicity and regarded as a ‘green reagent’ to replace existing noxious chemicals in the chemical industry, e.g. phosgene, methyl iodide or dimethylsulphate.
Cellulose can be converted into Cellulose MethylCarbonate (CellMC, Figure 1) in ionic liquid media.
Figure 1. Conversion of cellulose to Cell MC in [P8881][OAc]:DMSO with DMC.
After regenerate this allowed for a material that could be regenerated into films (Figure 2). Initial results showed modest water transmission and oxygen barrier properties. The sustainability of the process also needs improvment but this is a highly promising functionality to have in cellulose, little biopolymer degradation was observed and the system is recyclable.
Figure 2. Solvent-cast CellMC films.