Theoretical studies on thermal decomposition mechanism of arabinofuranose

Abstract

The thermal decomposition mechanism of arabinofuranose as hemicellulose model compound was investigated by using density functional theory methods M062X with the 6–31++G(d,p) basis set. Five possible pyrolytic reaction pathways were proposed and the standard kinetic parameters in all reaction pathways were calculated. In reaction pathway (1), arabinofuranose is transformed to acyclic containing-carbonyl isomer through a ring-opening reaction and the isomer further decomposes through five possible pyrolysis reaction pathways (1-1) ∼ (1-5). Reaction pathway (2) describes the evolutionary process of formic acid and reaction pathways (3)–(5) describe the formation process of furanones. The calculation results show that reaction pathways (1-2), (1-4) and (5) are the major reaction channels and reaction pathways (1-1), (1-5), and (2)–(4) are the competitive reaction channels in pyrolysis of arabinofuranose. The major pyrolysis products are low molecular products such as glycolaldehyde 4, acetaldehyde 12, 2-furaldehyde 20, 2-hydroxy-5-hydroxymethyl-furan-3-one 38 and CO. The main competitive products are formaldehyde, formic acid, ethanediol 5, acetol 9, 5-hydroxymethyl-furan-3-one 33, 5-hydroxymethyl-furan-2-one 36, CO2, H2, and so on.