Manufacture of Platform Chemicals from Pine Wood Polysaccharides in Media Containing Acidic Ionic Liquids

Abstract

Pinus pinaster wood samples were subjected to chemical processing for manufacturing furans and organic acids from the polysaccharide fractions (cellulose and hemicellulose). The operation was performed in a single reaction stage at 180 or 190 °C, using a microwave reactor. The reaction media contained wood, water, methyl isobutyl ketone, and an acidic ionic liquid, which acted as a catalyst. In media catalyzed with 1-butyl-3-methylimidazolium hydrogen sulfate, up to 60.5% pentosan conversion into furfural was achieved, but the conversions of cellulose and (galacto) glucomannan in levulinic acid were low. Improved results were achieved when AILs bearing a sulfonated alkyl chain were employed as catalysts. In media containing 1-(3-sulfopropyl)-3-methylimidazolium hydrogen sulfate as a catalyst, near quantitative conversion of pentosans into furfural was achieved at a short reaction time (7.5 min), together with 32.8% conversion of hexosans into levulinic acid. Longer reaction times improved the production of organic acids, but resulted in some furfural consumption. A similar reaction pattern was observed in experiments using 1-(3-sulfobutyl)-3-methylimidazolium hydrogen sulfate as a catalyst.

Performance of 1-(3-Sulfopropyl)-3-Methylimidazolium Hydrogen Sulfate as a Catalyst for Hardwood Upgrading into Bio-Based Platform Chemicals

“…The same IL was employed by Sievers et al [41] to obtain HMF and FF (at low mass yield) from loblolly pine using trifluoroacetic acid as a catalyst. López et al [38] employed 1-butyl-3-methylimidazolium hydrogen sulfate as a catalyst to achieve 60.5% conversion of pine wood pentosans into FF. Under the considered operational conditions, little conversion of cellulose into LevA was achieved, which is ascribed to the limited acidity of the catalyst.…”

“…[C3SO 3 Hmim]HSO 4 and [C4SO 3 Hmim]HSO 4 , two AIL of enhanced acidity (caused by the sulfonic group attached to the cation) have been successfully employed for processing purified cellulose and native LB. A near-quantitative conversion of xylosyl and arabinosyl groups in native pine wood into FF was achieved using these catalysts [38]. Concerning the production of LevA, 39.4-55% molar conversion was reached using microcrystalline cellulose as a substrate [26], [37], or 32.8% molar conversion of precursos (hexosans) in pine wood [38].…”

“…A near-quantitative conversion of xylosyl and arabinosyl groups in native pine wood into FF was achieved using these catalysts [38]. Concerning the production of LevA, 39.4-55% molar conversion was reached using microcrystalline cellulose as a substrate [26], [37], or 32.8% molar conversion of precursos (hexosans) in pine wood [38]. Obtaining higher LevA yields entailed the utilization of high catalyst charges (up to 4 g/g cellulose) [29], whereas the manufacture of soluble products from LB was favored when susceptible substrates of low lignin content (such as bagasse) were employed [42].…”

“…SO 3 H-functionalized ILs have been employed to achieve the dehydration of xylose into FF [34], whereas 1-butyl 3-methylimidazolium hydrogen sulfate ([bmim]HSO 4 ) has been employed to convert the hemicellulose fraction of lignocellulosic biomass into hemicellulosic sugars and FF [35], and to produce FF from xylose or soluble hemicellulose-derived saccharides obtained by the hydrothermal processing of Eucalyptus wood [32], eventually in the presence of a cosolvent [36]. Dealing with the conversion of cellulose, 1-(3-sulfopropyl)-3-methylimidazolium hydrogen sulfate ([C3SO 3 Hmim]HSO 4 ), alone or in combination with metal chlorides, has been employed for LevA production from pure cellulose [37]; whereas [C3SO 3 Hmim]HSO 4 and 1-(3-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([C4SO 3 Hmim]HSO 4 ) provided good results as catalysts for the conversion of Pinus pinaster wood polysaccharides [38]. Sulfonated ILs were successfully employed as catalysts to achieve the conversion of pure cellulose into LevA [26].…”