Consumption and over-exploitation of non-renewable resources, such as coal and oil contributed to the increased demand for lignocelluloses as a bio renewable feedstock [1]. Lignocelluloses (rice straw, bagasse, etc.) are the most abundant source of unutilized biomass comprising mainly of 40-50 % cellulose, 25-30% hemicellulose and 15-20% lignin which can be used for the production of value added products including cellulosic ethanol, fairness creams, platform chemicals, etc. [2] Anywhere in nature, except in cotton bolls, cellulose fibres are embedded in a matrix of different structural polymers. Prior to the utilization, first hurdle to overcome would be the primary conversion of the lignocelluloses considering the recalcitrant nature of such materials. This process known as pretreatment makes the material ready to use as a precursor for the manufacture of value added products but none of the methods existing now are established as efficient enough but are undeniably ‘non-green’ in nature[3]. T The quest for a better pretreatment solvents ended up using Ionic Liquids for the same application. Ionic liquids (ILs) are a new class of solvents which found suitable in different areas of research due to their interesting properties like high thermal stability, negligible vapour pressure, etc. [4] Till date, almost twenty ILs were found useful in biopolymer dissolution in which most of the studies are done with Imidazolium based ILs. In this study, we have synthesized diazabicyclo [5.4.0] undec-7-ene (DBU)-based protic ionic liquid, [DBU][OTf], and used it for the pretreatment of rice straw at two different temperatures 90 C and 120 C for 6 h. The pretreated solid was characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) Spectrum, and thermogravimetric analysis (TGA). DBU based ILs are comparatively new to this field and we do propose further analysis using a series of DBU ILs and coming up with a better explanation for the dissolution in the future prospective.
References:
[1] G. Brodeur, E. Yau, K. Badal, J. Collier, K. B. Ramachandran and S. Ramakrishnan, Enzyme Research, 2011, 2011, 1–17.
[2] J. A. Melero, J. Iglesias and A. Garcia, Energy and Environmental Science, 2012, 5, 7393–7420.
[3] D. A. Fort, R. C. Remsing, R. P. Swatloski, P. Moyna, G. Moyna and R. D. Rogers, Green Chemistry, 2007, 9, 63–69.
[4] H. Wang, G. Gurau and R. D. Rogers, Chemical Society Reviews, 2012, 41, 1519–1537.