Carbohydrate Polymers 159 (2017) 146–151 Contents lists available at ScienceDirect Carbohydrate Polymers j ourna l ho me pa g e: www.elsevier.com/locate/carbpol Synergistic effect of chloro and sulphonic acid groups on the hydrolysis of microcrystalline cellulose under benign conditions Firdaus Parveen, Kritika Gupta, Sreedevi Upadhyayula ∗ Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India a r t i c l e i n f o Article history: Received 6 October 2016 Received in revised form 4 December 2016 Accepted 7 December 2016 Available online 14 December 2016 Keywords: Hydrolysis Cellulose Copolymerised ionic liquid Glucose Synergistic effect a b s t r a c t The hydrolysis of cellulose catalysed by ionic liquid (IL) immobilized on chloromethyl vinyl benzene (CMVB) with different IL/CMVB ratio was carried out in water as a solvent. The influence of process variables like IL/CMVB ratio in catalyst, temperature and time were investigated in a batch reactor. It was found that 40% IL/CMVB catalyst afforded maximum%TRS and glucose yield 58.5 and 47.9% respectively at 160 ◦ C in 6 h reaction time. This can be attributed to the synergistic effect of chloro and sulfonic groups, to dissolve the cellulose by breaking the intra and inter molecular hydrogen bonds and cleave the -1, 4 glycosidic bonds respectively. The catalysts synthesized in the laboratory were characterized by FTIR, CHNS and TGA. The catalyst can be recovered three times without any significant loss in activity and characterized by FTIR to show the peaks of chloro and sulfonic groups in the recovered catalyst. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Biomass is a renewable feedstock that can overcome the prob- lems related to both depletion of fossil fuel as well as global warming. Biomass can be divided into three classes of feedstock: starchy, triglycerides and lignocellulose (Wyman et al., 2005). Starchy feedstock consists of polymer of glucose unit in the form of amylose and amylopectin, and can be easily hydrolyzed into sugar components and bioethanol. Triglycerides consist of glycerol and fatty acids from plant or animal origin and can be transformed into biodiesel. The fuels obtained from starchy and triglyceride feedstock constitute first generation fuels and compete with the food supply (Naik, Goud, Rout, & Dalai, 2010). Lignocellulose is an abundantly available non-food based biomass, majorly consisting of cellulose (40–50%) lignin (15–20%), and hemicellulose (25–35%). Lignocellulose based fuels are classified as second generation biofu- els. Cellulose is a highly crystalline structure consisting of repeated units of glucose linked via -1, 4 glycosidic bonds. Cellulose hydrol- ysis to glucose or direct conversion to biofuel is highly desirable. Cellulose transformation to furan derived fuels goes through vari- ous intermediates such as furfurals (Liu & Zhang, 2016b). One pot catalytic conversion of cellulose to furfurals can be achieved using magnetic catalysts and various solid acid catalysts with two types of ∗ Corresponding author. E-mail address: sreedeviupadhyayula@gmail.com (S. Upadhyayula). catalytic sites Lewis acidic and Bronsted acidic (Liu & Zhang, 2016a; Zhou & Zhang, 2016). However, the presence of extensive inter and intra molecular hydrogen bonding makes its structure recalci- trant towards hydrolysis (Huber, Iborra, & Corma, 2006; Remsing, Swatloski, Rogers, & Moyna, 2006; Vitz, Erdmenger, Haensch, & Schubert, 2009). Till date various schemes have been developed for the hydroly- sis of cellulose, such as mineral acid based catalysis, enzymes, solid catalyst and ionic liquids. However, these methods have their own drawbacks such as reactor corrosion, disposal of large quantity of gypsum (neutralization waste), expensive enzymes and harsh reac- tion conditions like high temperature, pressure and concentrated acids (Akpinar, Erdogan, & Bostanci, 2009). Ionic liquids are found to be promising catalysts for hydrolysis of cellulose and its disso- lution. However, their high cost limits the practical utility (Dong & Zhang, 2012; Swatloski, Spear, Holbrey, & Rogers, 2002). Bron- sted acidic ionic liquids with SO 3 H functionality are found to be better than COOH and OH functionalized ionic liquids for the hydrolysis of cellulose using BMIMCl as a solvent. The high cost of ionic liquid and its reusability always remain an issue of concern (Parveen, Patra, & Upadhyayula, 2016). Until recently, various results have been reported for the immo- bilization of ionic liquids on polymer, solid support, and silica. Amarasekara et al. reported silica supported ionic liquid for hydrol- ysis of cellulose to achieve 48% TRS (Total Reducing Sugar) yield (Wiredu & Amarasekara, 2014). Zhang et al. reported immobiliza- tion of sulphonic acid groups on the surface of silica encapsulated http://dx.doi.org/10.1016/j.carbpol.2016.12.021 0144-8617/© 2016 Elsevier Ltd. All rights reserved.