Gas‐Phase Reactions of Glyceraldehyde and 1, 3‐Dihydroxyacetone as Models for Levoglucosan Conversion during Biomass Gasification. Issue 7 (19th February 2016)

• Record Type: Journal Article
• Authors: Fukutome, Asuka; Kawamoto, Haruo; Saka, Shiro
• Is Part Of: ChemSusChem. Volume 9:Issue 7(2016:Apr.)
• Page Start: 703
• Page End: 712
• Publication Date: 2016-02-19
• Subjects: biomass -- carbohydrates -- density functional calculations -- gas-phase reactions -- pyrolysis; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201501612
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Levoglucosan, the major intermediate in wood gasification, is decomposed selectively to C1 /C2 fragments at 550–600 °C. Kinetic analyses suggest that radical chain mechanisms with the involvement of short‐lived carbonyl intermediates explain the lower production of larger fragments. To address this hypothesis, the gas‐phase reactivities of glyceraldehyde (Gald), 1, 3‐dihydroxyacetone (DHA), and glycerol, as simple C3 model compounds, were compared at 400–800 °C under N2 flow at residence times of 0.9–1.4 s. Retro‐aldol fragmentation and dehydration proceeded for the pyrolysis of Gald/DHA at 400 °C, far below the 600 °C decomposition point of glycerol. Pyrolysis of Gald/DHA generated exclusively syngas (CO and H2 ). On the basis of the results of theoretical calculations, the effects of carbonyl intermediates on reactivity were explained by postulating uni‐ and bimolecular reactions, although the bimolecular reactions became less effective at elevated temperatures. Abstract : Gas‐phase pyrolysis of sugars : Glyceraldehyde (aldose) and 1, 3‐dihydroxyacetone (ketose) are more reactive than glycerol during gas‐phase pyrolysis and are converted selectively to CO and H2 via methyl glyoxal, glycolaldehyde, and formaldehyde. The results suggest that bimolecular keto–enol tautomerization occurs, even in the gas phase.