Acid-catalyzed pyrolytic synthesis of levoglucosan through salt-mediated ring locking

Abstract

The combination of Na2SO4/H2SO4 increases levoglucosan (LGA) yield from glucose pyrolysis from 6% to as high as 40%, as a result of sodium suppressing the opening of the glucose ring.

High production of furfural by flash pyrolysis of C6 sugars and lignocellulose by Pd-PdO/ZnSO4 catalyst

“…S11a. Indeed, LGA has been frequently reported as one of the principal products from the pyrolysis of glucose or cellulose in fixed-bed reactors 18,54,55 . DFT modeling in a previous study also suggested that LGA is the most kinetically favored product from the dehydration of glucose 56 .…”

“…glucose, C 6 H 12 O 6 ) to furfural is more complex, requiring both dehydration and Grob fragmentation for the removal of hydroxyls (-OH) and the side group formaldehyde (HCHO), respectively. So far, the C6 sugars were mostly converted to 5-hydroxymethyl furfural (5-HMF, C 6 H 6 O 3 ) by solvolysis [11][12][13][14][15][16][17] , or to levoglucosan (LGA, C 6 H 10 O 5 ) [18][19][20] , and/or levoglucosenone (LGO, C 6 H 6 O 3 ) 11,21 by pyrolysis in Fig. 1b, A maximum selectivity of 15.9% for furfural was only achieved from the flash pyrolysis of cellulose at 600 °C16, 22-24 . Herein, we report a novel heterogeneous catalyst, namely, Pd-PdO/ZnSO 4 for the doping of 1.1 mol% Pd, on zinc sulfate (ZnSO 4 ) to produce furfural from the flash pyrolysis of C6 sugars (Fig.…”

Effect of metal triflates on the microwave-assisted catalytic hydrogenolysis of birch wood lignin to monophenolic compounds

“…LGA was significantly enhanced when the metal triflates were added with the exception of weaker Lewis acids [Mg(OTf) 2 ; Ca(OTf) 2 ], which could be ascribed to the acid-induced dehydration of glucose (Bouxin et al, 2019;Chen et al, 2020a;Zhao et al, 2018). The highest yield (6.5 wt%) of Xyl was achieved for Sc(OTf) 3 (pH=3.78), with a high yield of LGA (6.3 wt%) and FF (7.7 wt%).…”