The insights into the catalytic performance of rare earth metal ions on lactic acid formation from biomass via microwave heating

Coproduction of Glyceric Acid and Glycolic Acid from Biomass-Based Sugars over a Ru/Co3O4 Catalyst

“…These results illustrated that glyceric acid formation might proceed via glyceraldehyde as a precursor, while glycolaldehyde was the precursor of glycolic acid. Based on these results and those in the literature, 49,50 it was proposed that the transformation of xylose to glyceric acid and glycolic acid might involve the following (Figure 5c): (i) cyclic-xylose transformed to chainxylose via a ring-opening reaction, (ii) chain-xylose underwent C2−C3 cleavage yielding glyceraldehyde (C 3 intermediate) and glycolaldehyde (C 2 intermediate); and (iii) glyceraldehyde and glycolaldehyde were further oxidized to glyceric acid and glycolic acid, respectively. Based on this mechanism, the [glyceric acid]/[glycolic acid] ratio should theoretically be 1:1.…”

“…It is generally accepted that the transformation of xylose to C 2 and C 3 chemicals passes through complex cascade reactions, including ring-opening and C–C cleavage via a retro–aldol condensation reaction . Two possible C–C cleavage sites (C2–C3 or C3–C4) are generally considered to depend on the catalyst employed, which is considered as the key step in the process of xylose transformation to short-chain acids. , To clarify the reaction mechanism of xylose conversion to glycolic acid and glyceric acid, 4- 13 C-xylose was employed as the probe molecule to perform the isotopic probe experiment.…”

Homogeneous and Heterogeneous Catalysis of Glucose to Lactic Acid and Lactates: A Review

“…This generation of Brønsted acidity using sulfate could explain the decrease in LA yields, as Brønsted acidity favors fructose dehydration instead of the retro-aldol reaction pathway. 61 Elliot et al (2018) reported that the catalytic performances of salts of strong acids increase with the salt concentration until it reaches a plateau. 62 Indeed, a low concentration of strong salt is sufficient to get to total conversion, while higher salt concentrations do not affect the reaction.…”

“…Interestingly, placing Yb 2 (SO 4 ) 3 in water decreased the pH of the medium to 3.0. This generation of Brønsted acidity using sulfate could explain the decrease in LA yields, as Brønsted acidity favors fructose dehydration instead of the retro-aldol reaction pathway . Elliot et al (2018) reported that the catalytic performances of salts of strong acids increase with the salt concentration until it reaches a plateau .…”

Production of lactic acid mediated by compressed carbon dioxide on heterogeneous Ni(ii) catalysts: a facile approach

“…Thus, to stimulate the lactic acid yield, effective measures are harsh reaction conditions (temperature >200 °C) and the presence of stoichiometric amounts of bases, which restricted large-scale applications. 10,11 To avoid these obstacles, and to obtain an impressive yield of lactic acid or lactate, instead of carbohydrates, advances are made with glycerol (a side product of bio-diesel industry) 12 as well as high-priced oxidation products of glycerol such as glycolaldehyde, 13 pyruvaldehyde 14 and dihydroxyacetone 15 in an oxidative environment using mainly Cr and Sn salts under alkaline conditions but easy over-oxidation is a major issue.…”