Journal of Molecular Catalysis A: Chemical 394 (2014) 170–176 Contents lists available at ScienceDirect Journal of Molecular Catalysis A: Chemical jou rnal h om epa ge: www.elsevier.com/locate/molcata Elucidating the role of cobalt phthalocyanine in the dehydration of carbohydrates in ionic liquids Kumar Karitkey Yadav, Sohail Ahmad, Shive M.S. Chauhan ∗ Bio-organic Research Laboratory, Department of Chemistry, University of Delhi, Delhi 110007, India a r t i c l e i n f o Article history: Received 4 April 2014 Received in revised form 8 July 2014 Accepted 10 July 2014 Available online 18 July 2014 Keywords: Cellulose Metallophthalocyanines 5-Hydroxymethylfurfural 2,5-Diformylfuran 5-Ethoxymethylfurfural a b s t r a c t The cobalt(II) phthalocyanine efficiently converts glucose and cellulose into 5-hydroxymethylfurfural in [EMIm]Cl ionic liquid. From various throughout screening of metal salts, metallophthalocyanines and ionic liquids, the combination of cobalt phthalocyanine with [EMIm]Cl ionic liquid gave the best results. Co(II)Pc interacts with glucose in [EMIm]Cl ionic liquid and in situ generates the Co(I)Pc and Co(III)Pc which are confirmed from UV–visible analysis. Co(III)Pc reacts with glucose and generates five membered ring chelate complex, which subsequently isomerizes to fructose. In the reaction fructose easily dehydrats to HMF. A single-pot EMF and DFF are produced by etherification and aerobic oxidation reaction of glucose, respectively. The catalyst is easily separated from the reaction by simple filteration and recycled upto 3–5 times without the significant loss of its catalytic activity. © 2014 Elsevier B.V. All rights reserved. 1. Introduction In recent years, the increasing consumption of natural petroleum feedstock leads us to find an alternative source. All the forest plants, woods and herbaceous energy crops contain good amount of cellulose, hemicelluloses and lignin as major constituent [1]. The presence of extensive hydrogen-bonded networks and van der Walls interactions in sugar polymers, make it difficult to hydrolyze. Therefore the replacement of petroleum feedstocks with biomass requires the development of efficient and cost-effective procedure to convert carbohydrates to a variety of useful chemical compounds [2–4]. 5-Hydroxymethylfurfural (HMF) is an important organic compound which serves as a versatile intermediate between biomass-based carbohydrate chemistry [5,6] and petroleum-based industrial organic chemistry [7–9]. HMF and its derivatives poten- tially replace voluminously consumed petroleum-based building blocks, which are currently used to make plastics and fine chem- icals. HMF is easily converted into smaller building blocks [10] like 2,5-diformylfuran (DFF) [11], 2,5-furandicarboxylic acid [12], polyethyleneterephthalate [10], 5-(ethoxymethyl)furfural (EMF) ∗ Corresponding author. Tel.: +91 11 27666845/9871969266; fax: +91 11 27666845. E-mail address: smschauhan@chemistry.du.ac.in (S.M.S. Chauhan). [10], polybutyleneterephthalate [10], 2,5-dihydroxymethylfuran, [11] etc. Previously starting with glucose and fructose, many cat- alytic systems for the synthesis of HMF are reported in organic solvents [13], water [14], ionic liquids [15] and in microwave con- ditions [16]. These procedures require either protonic acid [17] or metal salt as a Lewis acid catalyst [18]. This acid catalyzed dehydra- tion of carbohydrates leads to various side-products like levulinic acid [19], formic acid [10], furfural [20], humic acid, etc. and sepa- ration of HMF is tough from these side products. However starting with cellulose and other feedstocks, very few literature reports are available and these procedures require higher temperature with higher pressure [10]. In this paper, we have developed a simple and convenient strat- egy for the dehydration of cellulose and glucose to HMF by using the Lewis acidic character of cobalt phthalocyanine. Recently we have carried out various organic transformations like oxidation, reduc- tion and dechlorination of various organic moieties [21] by using cobalt phthalocyanines as a catalyst. Thus metallophthalocyanines easily replace metal catalysts from organic transformations and provide better substitute. The unsubstituted metallophthalocya- nines are insoluble in common organic solvents but they easily interact with ionic liquids. Ionic liquids have been used as a green solvent to replace the conventional organic solvents due to their unusual properties particularly low vapor pressure and flamma- bility, highly concentrated ionic atmosphere, thermal stability, fast ion transport and ease of recyclability [22]. The combination of ionic liquids and metal salts are effective catalysts [23] for the hydrolysis http://dx.doi.org/10.1016/j.molcata.2014.07.014 1381-1169/© 2014 Elsevier B.V. All rights reserved.