Formation of lactic acid from glycolaldehyde by alkaline hydrothermal reaction

Non-stoichiometric formation of formic and levulinic acids from the hydrolysis of biomass derived hexose carbohydrates

“…Kishida et al, 20 detected formic acid yields of 5.3 mol% from glyceraldehyde at 300 C under alkali conditions.…”

“…For instance Kishida et al, achieved formic acid yields of 13 mol% at 300 C catalysed by NaOH. 20 Potential formic acid formation from D-glycolaldehyde is not investigated in our study due to the difficulty in obtaining it as reactant.…”

“…18 Formic acid has also been reported as a degradation product of well-known hexose decomposition products such as dihydroxyacetone, glyceraldehyde and pyruvaldehyde at high temperatures (>300 C) in subcritical water. 20,21 Joshi et al, using a zirconium dioxide catalyst suggested that the excess in formic acid is formed from a D-glucose starting material through the formation of 1,6-D-anhydroglucose which then subsequently undergoes hydrolysis forming furfural, formic acid and hydrogen stoichiometrically. 12 Moreover, of recent signicance is the study conducted by Yang et al, who used computational density functional theory to elaborate a "micro-kinetic" model for the glucose/Bronsted acid aqueous system.…”

Enhanced methane and hydrogen yields from catalytic supercritical water gasification of pine wood sawdust via pre-processing in subcritical water

“…The pH of the liquid residuals were 7.88 for LA, 2.18 for LB and 2.15 for LN; these pH values indicate that both neutral and Nb 2 O 5 pre-processing routes produced acidic liquid residuals, which could result from the presence of simple organic acids such as acetic and lactic acids [12,[31][32][33]. The liquid residual LA, from the alkaline preprocessing appeared darker and contained more carbon than those from either the Nb 2 O 5 or neutral pre-processing, according to TOC results.…”

“…It would appear that different mechanisms were involved during alkaline, neutral and acidic pre-treatment processes. For instance, neutral and acid treatment of biomass mostly involved dehydration [27], while the use of alkaline additives led to biomass degradation to simple water-soluble molecules [10,[31][32][33]. Research has shown that hydrothermal degradation of biomass could proceed via two distinct routes depending on the reaction medium [10,34].…”