%0 Journal Article
%T Br£¿nsted Acidic Ionic Liquid 1-(1-Propylsulfonic)-3-methylimidazolium-Chloride Catalyzed Hydrolysisof D-Cellobiose in Aqueous Medium
%A Ananda S. Amarasekara
%A Bernard Wiredu
%J International Journal of Carbohydrate Chemistry
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/948652
%X Br£¿nsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride (PSMIMCl) shows a higher catalytic activity than sulfuric acid in the hydrolysis of D-cellobiose to D-glucose in water at 90¨C120¡ãC. This catalytic activity enhancement is more significant at higher temperatures, and at 120¡ãC, PSMIMCl produced 64.5% glucose yield, whereas H2SO4 produced only 42.2% after 40£¿min. reaction, and this is a 52.8% enhancement of catalytic activity due to the alkylimidazolium group attached to the sulfonic acid group. 1H NMR monitoring of the D-cellobiose hydrolysis in PSMIMCl and sulfuric acid mediums failed to reveal intermediates in the hydrolysis reaction, and this is probably due to rapid conversion of the intermediate(s) to a mixture of D-glucose anomers with . 1. Introduction Hydrolysis of lignocellulosic biomass to fermentable sugars is an essential step in the production of cellulosic-ethanol and is the most challenging step in the whole process [1¨C5]. Enzymatic hydrolysis is the widely used technology in current pilot plants, but this method requires a drastic pretreatment at high temperature and pressure to disrupt the strong hydrogen bonding network in cellulose, before exposure to the enzyme. Furthermore, commercialization of the enzymatic process is hindered by the prohibitive cost of the currently available enzyme preparations as well [6]. As an alternative to the enzymatic methods, dilute aqueous solution of sulfuric acid can also be used as a catalyst for the direct hydrolysis of cellulose at high temperature and pressure. Even though, the direct dilute acid saccharification gives lower sugar yields compared to enzymatic saccharification, a number of research groups have taken an interest in this old process [7¨C9] taking a second look at this technology due to its simplicity, and lower cost when compared to enzymatic saccharification, which anyhow requires an energy consuming pretreatment. Ionic liquids are well known for their unique combination of attractive properties and as green solvents for numerous applications, but currently there is a marked interest in using ionic liquids in a number of other functions such as electrolytes [10], polymeric materials [11, 12], and catalysts [13]. In addition to this, 2002 discovery [14] of the use of ionic liquids as a cellulose dissolving solvent has sparked a new field of research on the use of ionic-liquid-based systems for the depolymerization of cellulose. The initial efforts in this direction were reported by Li et al. in 2007, where they published the use of catalytic amount of H2SO4
%U http://www.hindawi.com/journals/ijcc/2012/948652/