411 / 2018-07-25 17:37:26

Thermo Conversion of Monosaccharides of Biomass to Oligosaccharides Via Mild Conditions

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The conversion of monosaccharides, such as glucose and xylose, to valuable compounds is very important considering the downstream chemical processing from lignocellulosic biomass. A novel and green approach for production of oligosaccharides (Cello-oligosaccharides and Xylo-oligosaccharides) from monosaccharides (glucose and xylose) of biomass by thermo conversion in nitrogen atmosphere under mild conditions was investigated. The exploration of optimal conditions was used to evaluate the conversion process which showed the conversion procedure was similarly under varied reaction temperatures, and it can be summarized into three stages, i.e. water evaporation stage, formation of oligosaccharide stage and complete decomposition of monosaccharides stage. Oligosaccharides yield that more than 40% can be obtained by adjusting the reaction time under varies temperatures, and the air was considered to be the appropriate quenching method for low temperature preparation process. The highest oligosaccharides yields (above 47%) and selectivities (above 75%) of this study could be reached within few seconds without introduce any chemical reagent. Besides, the optimized thermo conversion temperature was at 500℃, and the by-products in precursor oligosaccharides were analyzed by IC, HPLC, HRMS, MALDI-TOF MS. Simultaneously, the thermal decomposition characteristics of precursor oligosaccharides were demonstrated. Finally, the possible reaction pathways for monosaccharides of biomass to oligosaccharides in sugar pyrolysis system were also proposed, meanwhile, stage of oligosaccharides production was an important transition state for other functional products in sugar pyrolysis system.