The presence of heavy unknown oligomeric sugar products in bio-oil is evidenced in experimental results reported in the literature. In this paper, we study the fragmentation reactions yielding hydroxyacetone and hydroxyacetaldehyde from oligomeric sugars following previous work on dehydration reactions to propose structures of these oligomers. Hydroxyacetone and hydroxyacetaldehyde are primary products of cellulose fast pyrolysis, but the fragmentation reaction mechanism of these compounds from oligomers merits further study. The density functional theory approach was employed to study this reaction. Results revealed that hydroxyacetone and hydroxyacetaldehyde fragments are more favorably removed from the nonreducing end based on their thermodynamic stabilities. As a result of this study, we proposed new potential structures of unknown oligomeric sugars. Theoretical FTIR and NMR spectra were calculated so that in the future when these molecules are separated their experimental spectra and the theoretical ones herein reported can be used to confirm the structures of these oligomeric sugars. Also, the thermodynamics and physical properties of these compounds were estimated by using the group contribution method. These properties are essential in the design of technologies for bio-oil refining.
ASJC Scopus subject areas
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology