DEVELOPMENT OF IONIC LIQUID TECHNOLOGIES FOR THE INTEGRATION OF PRE-TREATMENT, FRACTIONATION, EXTRACTION, HYDROLYSIS AND CONVERSION OF BIOMASS IN THE FRAME OF THE BIOREFINERY CONCEPT

Two innovative strategies for biomass valorization with ionic liquids (ILs) were approached in this work. A first strategy was based on a three-step fractionation of lignocellulosic biomass into cellulose, hemicellulose and lignin assisted by 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). Simultaneously, this IL allowed further valorization by extraction of high value added phenolic compounds from biomass during the process. Purification of vanillin, tricin, p-hydroxybenzaldehyde, syringaldehyde, p-coumaric and vanillic acids from IL was accomplished using polymeric resins and supercritical CO2. The second strategy was focused on the ability of acidic ILs, such as 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim][HSO4]) and 1-ethyl-3-methylimidazolium hydrogen sulfate ([emim][HSO4]), to hydrolyze and to convert selectively hemicellulose into reducing sugars and furans. In this scenario, depending on specific properties of ILs, such as basicity and acidity, biomass is physically and chemically altered allowing the integration of biomass pre-treatment, fractionation, hydrolysis and conversion processes to produce desired compounds.