Qiao, Yan2; Pedersen, Christian Marcus3; Wang, Yingxiong2; Hou, Xianglin2
1 Administration, Department of Chemistry, Faculty of Science, Københavns Universitet2 Chinese Academy of Sciences3 Administration, Department of Chemistry, Faculty of Science, Københavns Universitet
The solvent properties of ZnCl2 molten salt medium and its synergic effect with the Lewis acid catalyst, Sn4+, for biomass conversion, were investigated by nuclear magnetic resonance. The tautomeric distribution of fructose in the ZnCl2 molten salt medium was examined, and its effect for humins formation during the biomass conversion was evaluated. The ion complex composed by Sn4+ and Zn2+ indicated that there is a synergic catalytic effect between these two Lewis acid ions. 13C NMR spectra of fructose in different ZnCl2 molten salt hydrate concentrations revealed that the concentration of β-furanose and α-furanose tautomers, which lead to 5-HMF, were significantly decreased with increased salt concentration. Meanwhile the β-pyranose tautomer, which is correlated with humins formation, was increased significantly.
A C S Sustainable Chemistry and Engineering, 2014, Vol 2, Issue 11, p. 2576-2581
5-HMF; Fructose; Molten salt hydrate medium; NMR; ZnCl