Transformation of cellulosic saccharides into alkyl glucosides catalyzed by bifunctional ionic liquids

Abstract

Three kinds of hydrophobic/acidic bifunctional ionic liquids were synthesized and utilized as catalysts for the conversion of cellulosic saccharides into alkyl glucosides, which exhibit a high catalytic conversion for cellobiose and cellulose with a low degree of crystallinity; the catalyst can be easily recovered and reused.

Hydrodeoxygenation of potential platform chemicals derived from biomass to fuels and chemicals

“…Similar to the hydrolysis of cellulose in water, 107–110 alcoholysis is also accelerated in the presence of acid catalysts such as heteropolyacids, 111 sulfonated carbon, 112 and mesoporous zeolite. 113 Likewise, the combination of acid catalysts and ionic liquids, the latter of which are effective for improving the reactivity of cellulose, has achieved outstanding yields of alkyl glucosides; 114–116 for example, a hydrophobic and acidic bifunctional ionic liquid produced 93.1% yield of methyl glucosides including both α- and β-anomers from ball-milled cellulose ( i.e. , amorphous cellulose) at 413 K for 4 h. 115 Jérôme et al reported that after the sulfuric acid-assisted mechanochemical reaction of cellulose induced by ball-milling, which was the same procedure first reported for cellulose hydrolysis, 117–119 the resulting cello-oligosaccharides were easily converted in 1-butanol into n -butyl glucosides in 70% yield at a relatively low temperature of 390 K for 3 h. 120 Such mild alcoholysis conditions are favorable for the production of desired alkyl glucosides, since under harsh conditions in the presence of acids, alkyl glucosides undergo further transformation into 5-alkoxymethylfurfural and alkyl levulinate.…”

“…113 Likewise, the combination of acid catalysts and ionic liquids, the latter of which are effective for improving the reactivity of cellulose, has achieved outstanding yields of alkyl glucosides; 114–116 for example, a hydrophobic and acidic bifunctional ionic liquid produced 93.1% yield of methyl glucosides including both α- and β-anomers from ball-milled cellulose ( i.e. , amorphous cellulose) at 413 K for 4 h. 115 Jérôme et al reported that after the sulfuric acid-assisted mechanochemical reaction of cellulose induced by ball-milling, which was the same procedure first reported for cellulose hydrolysis, 117–119 the resulting cello-oligosaccharides were easily converted in 1-butanol into n -butyl glucosides in 70% yield at a relatively low temperature of 390 K for 3 h. 120 Such mild alcoholysis conditions are favorable for the production of desired alkyl glucosides, since under harsh conditions in the presence of acids, alkyl glucosides undergo further transformation into 5-alkoxymethylfurfural and alkyl levulinate. 121,122 The direct production of alkyl glycosides via alcoholysis has also been reported for other poly- or oligo-saccharides such as starch, 123,124 which consists of glucose linked by α-1,4-glycosidic bonds and is known to undergo depolymerization more easily than cellulose, 108 and mannotetraose, 125 which is a tetramer of mannose connected by β-1,4-glycosidic bonds and a model compound of naturally occurring β-mannan.…”

Fischer–Helferich glycosidation mechanism of glucose to methyl glycosides over Al-based catalysts in alcoholic media

“…13 The glucose could form alkyl glucoside in the alcohol system through Fischer-Helferich glycosidation which is described in Scheme 1. 14,15 Fischer-Helferich glycosidation is one of the most promising choices to prepare alkyl or aryl glycosides from sugars. Most studies have concentrated on the conversion experiments and development of high-efficiency catalysts due to the wide application of high value-added alkyl glucosides.…”

“…(1)(2)(3)(4)(5)(6)(7)(8)(9)(10) four-(11)(12)(13)(14)(15)(16)(17)(18) five-(19)(20)(21)(22)(23)(24) and six-(25-28) membered ring-closure reaction from IM2. (unit kcal mol À1 ) bond length.…”