Oxalic acid

About: Oxalic acid is a research topic. Over the lifetime, 11584 publications have been published within this topic receiving 173263 citations. The topic is also known as: ethanedioic acid & H2ox.

Molecular distributions of dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in biomass burning aerosols : implications for photochemical production and degradation in smoke layers

Abstract: Aerosols in the size class 2 –C 11 ) and related compounds (ketocarboxylic acids and α-dicarbonyls) were identified using gas chromatography (GC) and GC/mass spectrometry (GC/MS). Among the species detected, oxalic acid was found to be the most abundant, followed by succinic, malonic and glyoxylic acids. Average concentrations of total dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the aerosol samples were 2180, 167 and 56 ng m −3 , respectively. These are 2–8, 3–11 and 2–16 times higher, respectively, than those reported in urban aerosols, such as in 14 Chinese megacities. Higher ratios of dicarboxylic acids and related compounds to biomass burning tracers (levoglucosan and K + ) were found in the daytime than in the nighttime, suggesting the importance of photochemical production. On the other hand, higher ratios of oxalic acid to other dicarboxylic acids and related compounds normalized to biomass burning tracers (levoglucosan and K + ) in the daytime provide evidence for the possible degradation of dicarboxylic acids (≥C 3 ) in this smoke-polluted environment. Assuming that these and related compounds are photo-chemically oxidized to oxalic acid in the daytime, and given their linear relationship, they could account for, on average, 77% of the formation of oxalic acid. The remaining portion of oxalic acid may have been directly emitted from biomass burning as suggested by a good correlation with the biomass burning tracers (K + , CO and EC a ) and organic carbon (OC). However, photochemical production from other precursors could not be excluded.

The use of manganese dioxide as a heterogeneous catalyst for oxalic acid ozonation in aqueous solution

Abstract: Heterogeneous catalysis by MnO2 of oxalic acid ozonation in aqueous solution has been investigated in the pH range 3.2–7.0. The influence of catalyst load and reaction temperature upon rate development of the ozonation process has also been examined. The observed dependence of system reactivity on pH and the results obtained by ozonation experiments with MnO2 catalysts of different pHzpc values agree with a reaction mechanism involving the formation of a surface Mn - oxalic acid complex.