The Conversion of Fructose and Glucose in Acidic Media: Formation of Hydroxymethylfurfural

Abstract

The effects of several variables on the reactions of fructose and glucose in acidic media have been studied at moderate reaction conditions. Glucose gives rise to the reversible formation of oligosaccharides (reversion products). Fructose was dehydrated into mixtures of hydroxymethylfurfural, levulinic acid, and humines. In addition, substantial reversible dimerisation of fructose occurred in acidic aqueous solutions. The dimerisation equilibrium, which is shifted by a decrease in the water concentration, lowers the concentration of reactive fructose thereby affecting the selectivity of the dehydration process. p-Toluenesulfonic acid proved to be the most effective catalyst for the formation of HMF from fructose. No specific salt effects were found for the hydrochloric acid catalyzed dehydration of fructose. Die Umwandlung von Fructose und Glucose in sauren Medien: Bildung von Hydroxymethylfurfural. Die Wirkungen verschiedener Variablen auf die Reaktionen von Fructose und Glucose in sauren Medien wurden bei maBigen Reaktionsbedingungen untersucht. Glucose fuhrte zur reversiblen Bildung von Ohgosacchariden (Reversionsprodukten). Fructose wurde zu Mischungen von Hydroxymethylfurfural, Laevulinsaure und Huminen dehydratisiert. Zusatzlich trat in betrachtlichem MaBe reversible Dimerisierung von Fructose in sauren wassrigen Losungen auf. Das Dimerisierungsgleichgewicht , welches durch Verringerung der Wasserkonzentration verschoben wird, vermindert die Konzentration an reaktiver Fructose und beeinfluat damit die Selektivitat des Dehydratisierungsprozesses. p-Toluolsulfonsaure envies sich als der wirkungsvollste Katalysator fur die Bildung von HMF aus Fructose. Fur die durch Salzsaure katalysierte Dehydratisierung von Fructose wurde kein spezifischer Salzeffekt gefunden. _______ starchistarke 38 (1986) Nr 3, S. 95-101 starchlstarke 38 (1986) Nr. 3, S . 95-101

Synthesis, Chemistry and Applications of 5‐Hydroxymethyl‐furfural and Its Derivatives

“…Antal et al 21 analysed very profoundly the reaction of sugar decomposition in an aqueous solution and they found four groups of products formed in the course: the isomerisation, the dehydration, the fragmentation and the condensation. Van Dam 22 and Cottier 23 showed that the aqueous and nonaqueous processes led to about 37 products. They demonstrated that the reactions carried out in an aqueous medium provoked the degradation of HMF and that the polymerisation occurred in both aqueous and non-aqueous media.…”

Liquid‐Phase Catalytic Processing of Biomass‐Derived Oxygenated Hydrocarbons to Fuels and Chemicals

“…[6] The HMF product can also undergo further rehydration to form levulinic acid and formic acid in the presence of water. [63] Previous studies suggested that HMF formation can take place through an open-chain 1,2-enediol mechanism or through fructofuranosyl intermediates. [24,27,64] However, Antal et al showed that the formation of HMF from fructose proceeds via cyclic intermediates, providing evidence such as 1) facile conversion of 2,5-anhydro-dmannose (an intermediate enol in cyclic mechanism) to HMF; 2) facile formation of HMF from the fructose part of sucrose; and 3) lack of carbon-deuterium bond formation in HMF owing to keto-enol tautomerism in the open-chain mechanism when the reaction is carried out in D 2 O.…”

Green Chemicals from d-glucose: Systematic Studies on Catalytic Effects of Inorganic Salts on the Chemo-Selectivity and Yield in Aqueous Solutions

“…For instance, Van Dam et al studied the dehydration of D-fructose using HCl as the catalyst [11]. The presence of certain salts (e.g.…”