Abstract: The degradation of β-D-glucose in formic acid solution has been studied. The effects of temperature (55-75℃) and retention time (0-2h) have been investigated. It has been revealed that β-D-glucose is only marginally degraded in formic acid, but severely degraded in formic acid with hydrochloric acid. The degradation products of β-D-glucose at 75℃ for 4h have been analyzed by GC-MS. The main degradation products are 1,3-dihydroxyl-2-acetone and hydroxyl acetaldehyde in 88% formic acid, however 5-methoxyl furfural in formic acid with hydrochloric acid. The route of degradation is the protonation and cleavage of the hydroxyl group on the C-4 in formic acid, while on the C-2 in formic acid with hydrochloric acid, where the protonation of hydroxyl group results in the rearrangement of carbon cation before completing the dehydration reaction. Experimental observations supported these two degradation pathways.

Key words: β-D-glucose, formic acid, degradation, mechanism