abstract
The one-pot hydrolysis/dehydration of mono/di/polysaccharides into furfural (FUR) or 5-hydroxymethyl-2-furaldehyde (HMF) in the presence of an acidic ionic liquid. 1-ethyl-3-methylimidazolium hydrogen sulfate ([EMIM][HSO(4)]), at 100 degrees C, was investigated and the results were compared with those using 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), with or without CrCl(3) or H(2)SO(4). The ionic liquid [EMIM][HSO(4)] is effective in converting xylose and fructose or related polysaccharides into FUR (e.g. from xylose: 84% yield at 6 h) or HMF (e.g. from fructose: 88% yield at 30 min), but not glucose and polymers containing these units, which contrasts to that observed for the [BMIM][Cl]/CrCl(3) system. The latter is quite effective in converting glucose and related disaccharides into HMF, but not the polysaccharides cellulose and starch. For the latter feedstocks, the addition of H(2)SO(4) or [EMIM][HSO(4)] to cellulose/[BMIM][Cl]/CrCl(3) enhances HMF yields, presumably by accelerating the hydrolysis step, although the selectivity of the dehydration of glucose monomers seems rather poor (HMF yield < 13 wt.%). In the case of the xylose to FUR conversion in [EMIM][HSO(4)], two systems involving the reaction and simultaneous separation of the target product were investigated, namely reaction/solvent extraction and reaction/evaporation systems, and for both the ionic liquid could be recovered and reused without a significant drop in FUR yield in recycling runs. (C) 2009 Elsevier B.V. All rights reserved.
keywords
D-FRUCTOSE; DEHYDRATION; BIOMASS; FUELS; WATER; DECOMPOSITION; DISSOLUTION; CHEMICALS; CELLULOSE; CATALYST
subject category
Chemistry; Environmental Sciences & Ecology
authors
Lima, S; Neves, P; Antunes, MM; Pillinger, M; Ignatyev, N; Valente, AA
our authors
Anabela Tavares Aguiar Valente
Principal Researcher
Maria Margarida Feitor Pintão Moreno Antunes
Junior Researcher
Martyn Pillinger
Principal Researcher
Patrícia dos Santos Neves
Assistant Researcheracknowledgements
We are grateful to the FCT, POCI 2010, OE and FEDER for funding (Projects POCI/QUI/56112/2004 and PTDC/QUI/71198/2006). We acknowledge Dr. F. Domingues (Department of Chemistry) for access to HPLC equipment. S.L. is grateful to the FCT for a post-doctoral grant and P.N. for a grant from CICECO (FCT funding).