Mediating acid-catalyzed conversion of levoglucosan into platform chemicals with various solvents

Abstract

Acid-catalyzed conversions of levoglucosan have been investigated in mono-alcohols, poly-alcohols, water, chloroform, toluene, acetone, N,N-dimethyl formamide, dimethyl sulfoxide and some mixed solvents, aiming to mediate conversion of sugars into platform chemicals with solvents. The monoalcohols can stabilize soluble polymers and thus suppress formation of insoluble polymers. Water does not have such an effect, leading to lower yields of levulinic acid. Chloroform cannot effectively dissolve levoglucosan, leading to "dissolving" of levoglucosan in the catalyst and the consequent rapid polymerization. Acetone reacted with sugars, forming substantial amounts of polymer. N,N-Dimethyl formamide poisoned the acid resin catalyst, leading to negligible conversion of levoglucosan. Dimethyl sulfoxide (DMSO) mainly catalyzed the conversion of levoglucosan into 5-(hydroxymethyl)furfural (HMF), 2,5-furandicarboxaldehyde, and the sulfur ether of HMF. DMSO has a low ability to transfer protons, which helps to avoid further contact of HMF with catalytic sites and stabilizes HMF.

Deactivation of solid catalysts in liquid media: the case of leaching of active sites in biomass conversion reactions

“…This behavior has been found in ion exchange resins employed in the esterification of bio-oils, where the main cause of deactivation was ion exchange with metal ions. 38 . Therefore, the presence of impurities in the initial feedstock can potentially deactivate the 10 catalyst.…”

Acid-catalyzed conversion of C6 sugar monomer/oligomers to levulinic acid in water, tetrahydrofuran and toluene: Importance of the solvent polarity

“…Detailed procedures can be found in our previous work [7,9,11]. In a typical experiment, 11.9 g sugar and 18.1 g A70 in its wet form or 8.15 g in its dry form (equals to 18.1 g wet catalyst) were mixed with 85 ml solvent and loaded into autoclave.…”

“…Due to the important roles of solvents, a wide range of solvents have been evaluated for acid-catalyzed conversion of sugars including alcohols [7][8][9][10][11], ionic liquids [12][13][14][15], DMSO [16,17], sulfolane [18], imidazolium chloride-based solvents [19,20], glycerol carbonate [21], N,N-dimethyl formamide [22], alkylphenol [23], biphasic solvent [24] and others. The criteria for selection of these solvents depend on their interactions with sugars and/or products, their polarities and so on.…”

Steam reforming of bio-oil derived small organics over the Ni/Al2O3 catalyst prepared by an impregnation–reduction method

“…It should be clarified that the simulated bio-oil here is different from the bio-oil produced from the pyrolyzed biomass. The pyrolyzed bio-oil contains a number of light and heavy organic compounds, including the sugar derived light components (i. e. carboxylic acids, aldehydes, ketones and alcohols), sugars (i. e. glucose, levoglucosan, and xylose), and phenolics (i. e. phenol and other big aromatics) [23][24][25][26][27][28].…”