Topic
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.
Papers published on a yearly basis
Papers
More filters
TL;DR: This photocatalytic system can be applied for reduction of aminonitrobenzenes to corresponding diaminobenzenes (DAB) in the presence of oxalic acid as a hole scavenger and high yields of m-ABS and DAB were achieved even when the reactions were performed in the absence of oxygen.
Abstract: Photocatalytic reduction of nitrobenzenes to corresponding aminobenzenes in aqueous suspensions of titanium(IV) oxide (TiO2) containing hole scavengers under various conditions was examined. In photocatalytic reduction of m-nitrobenzenesulfonic acid (m-NBS) in the presence of formic acid (FA) under deaerated conditions, m-aminobenzenesulfonic acid (m-ABS) was produced almost quantitatively in acidic suspensions and high efficiency (>99%) in FA utilization as a hole scavenger was achieved. No re-oxidation of m-ABS occurred in acidic conditions both in the presence and absence of FA. The high yield of m-ABS was explained by strong ability of FA as a hole scavenger and possible repulsion of the reduced functional group (ammonium group, –NH3+) from the protonated, i.e., positively charged TiO2 surface in acidic suspensions avoiding re-oxidation of m-ABS. Using TiO2 samples of various physical properties, which had been synthesized by a solvothermal method and post-calcination at various temperatures, effects of physical properties of the TiO2 samples on m-ABS yield were also investigated. A linear correlation between the amount of m-NBS adsorbed and the m-ABS yield was observed, suggesting that ability of TiO2 for m-NBS adsorption is one of the key factors for effective photocatalytic reduction of m-NBS to m-ABS. This photocatalytic system can be applied for reduction of aminonitrobenzenes to corresponding diaminobenzenes (DAB) in the presence of oxalic acid as a hole scavenger. High yields of m-ABS and DAB were achieved even when the reactions were performed in the presence of oxygen.
91 citations
TL;DR: The electrochemical oxidation of phenol in basic media using a diamond thin-film electrode has been studied in this paper, where the main intermediates formed are maleic, fumaric, and oxalic acids.
Abstract: The electrochemical oxidation of phenol in basic media using a diamond thin-film electrode has been studied. Within the parameter ranges used (temperature: 15−60 °C, initial total carbon concentration: 360−1450 mg of C dm-3; current density: 15−60 mA cm-2), almost complete mineralization of the organic waste is obtained. The mineralization rate increases with current density and temperature. Current efficiency depends mainly on mass transfer limitations: in the absence of mass transfer limitations, instantaneous current efficiencies of 1 are obtained. The main intermediates formed are maleic, fumaric, and oxalic acids. A simple model based on mass transfer and kinetic considerations, which involves four species (phenol, maleic/fumaric acid, oxalic acid, and carbon dioxide), can be used to explain the experimental behavior of the system, regardless of the conditions applied.
91 citations
TL;DR: In this paper, the effect of organic (acetic, oxalic, citric) and inorganic (hydrochloric, nitric, sulfuric) acids on the dissolution of ripidolite was studied at 25°C over an acid concentration range of 0.03 to 10 mM.
Abstract: Although chlorites are an important source of Mg and micronutrients in soils, little is known about their weathering behavior in acidic environments. The effect of organic (acetic, oxalic, citric) and inorganic (hydrochloric, nitric, sulfuric) acids on the dissolution of ripidolite was studied at 25°C over an acid concentration range of 0.03 to 10 mM. The increasing ripidolite dissolution with increasing acid concentration can be described by the same empirical equation for all six acids used in this study. Because proton and ligand promoted dissolution mechanisms are additive, the influence of ligands can be calculated by subtracting the influence of protons from the total dissolution of ripidolite. We assume that the influence of Cl - in HCI systems can be neglected. Greater dissolution of ripidolite in the presence of the other acids at the same pH is attributed to the accompanying anion. At pH 3.5 and an anion concentration of 10 -35 mol L -1 , the relative effectiveness of the acids used in this experiment in promoting dissolution was nitric (enhancement factor: 0.97) = hydrochloric (1.00) ≅ acetic (1.01) < sulfuric (1.19) < citric (2.70) < oxalic acid (3.27). The dissolution of ripidolite was nonstoichiometric with a preferential release of Si relative to Al, Fe, and, in some cases, Mg at low proton and ligand concentrations for all six acids. At higher acid concentrations the dissolution becomes almost stoichiometric in the presence of inorganic acids, whereas in the presence of oxalic acid Al, Fe, and Mg were released preferentially relative to Si. In the presence of citric acid, Fe is released preferentially relative to Si. The alteration of chlorites in soils and the amount of released elements into the soil solution therefore depends on the composition of acidifying agents in soils.
91 citations
TL;DR: The role of iron on the degradation of different organic compounds, differing in their structure (aliphatic versus aromatic) and iron complex formation capacity, by conventional and photo-Fenton processes was investigated in this paper.
91 citations
TL;DR: In this article, the degradation of lipidic paint binders induced by irradiation with UV light (365 nm), exposure to urban air pollutants such as NOx and SO2 and combinations of the various treatments was investigated.
90 citations