Tuesday, April 20, 2010
8-83

Tributyl methyl phosphonium methyl sulphate dissolution of hemicelluloses from bagasse

Sai Keskar, Les Edye, and William Doherty. Queensland University of Technology, 2 George St, Brisbane, Australia

The dissolution of sugarcane bagasse was studied in the ionic liquid (IL) tributyl methyl phosphonium methyl sulphate. The FTIR results and the recovered dissolved fractions show that this hydrophilic IL can effectively remove lignin and hemicelluloses. The results obtained were compared to the results from the dissolution of bagasse in hydrophobic trihexyl tetradecyl phosphonium chloride. While the hydrophobic IL could not dissolve any hemicellulose, the hydrophilic IL had a significant capacity to dissolve hemicelluloses. This was confirmed by dissolution of isolated hemicellulose standards in the IL. Both ILs dissolved lignin to varying degrees depending on the temperature of the reaction. Unlike trihexyl tetradecyl phosphonium chloride, the dissolved fractions in tributyl methyl phosphonium methyl sulphate can be precipitated using an antisolvent  (water) and characterized. The lignin recovered from the IL was characterized using gel permeation chromatography. The results suggest that dissolution of cellulose and hemicellulose could be related to the hydrophilic nature of the ILs as most of the imidazolium ILs that dissolve cellulose and hemicellulose are hydrophilic.