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2 into Industrial Products
Published in Ashok Kumar, Swati Sharma, 2 Utilization, 2020
Ramya Thangamani, Lakshmanaperumal Vidhya, Sunita Varjani
The oxalic acid is generally produced from oxalate salt; however, it can also be produced under laboratory conditions by the cationic reduction of CO2 in an electrolytic cell. The porous membrane separates the anode and cathode compartments, and the catholyte acts as an organic solvent. The preferred solutes for the catholyte are tetraethylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, and tetraethylammonium p-toluenesulfonate. When the anolyte remains the same electrolyte and the solvent as the catholyte, the coulombic yields are as high as 75%. However, close to 97% of sodium oxalate is also obtained when the aqueous solution of sodium salt is used as the anolyte. This process involved in the synthesis of alkali metal salts of glycolic acid, ethylene glycol, alkali metal salts of nitrilotriacetic acid by the hydrogenation of oxalic acid or an alkali metal hydrogen oxalate, alkali metal salts of diglycolic acid and alkali metal salts of glycine may sometimes contain ammonia or otherwise oxalic acid or alkali metal hydrogen oxalate that contains less than two moles of water.
2 Utilization
Published in S. Komar Kawatra, Advanced Coal Preparation and Beyond, 2020
Oxalic acid (H2C2O4) can be used to leach rare earths from minerals. The rare earths, a national security resource, are used in the production of advanced technology ranging from smartphones and defense to medicine and complex chemical catalysts. Oxalic acid is formed from the dimerization of CO2 in the presence of hydrogen, as in Equation 17.14. Oxalic acid is one of the strongest organic acids, and has intriguing ligand properties for selectively solubilizing and insolubilizing metal cations. Oxalic acid shares many of the same uses as formic acid, but is also used in rare earth leaching (Sawada and Murakami, 2000). 2CO+H2→H2C2O4
Corrosion Resistance
Published in Frank Porter, Zinc Handbook, 1991
The remedy is to swab with a cold-water solution of commercial quality oxalic acid solution (or alternatively use a domestic kettle scale remover) followed by rinsing with water. Oxalic acid is toxic: rubber gloves and goggles are recommended. Cement and Mortar Stains. Portland cement mortar droppings tend to adhere strongly to zinc and when fully hardened are often difficult to remove completely without damaging the metal.
Synergistic effect of pH and oxalate concentration on corrosion of aluminium alloy 2024-T3
Published in Corrosion Engineering, Science and Technology, 2018
Alexander Hoyt, Shengxi Li, Xinyan Dai, Camila Garcia, Hongbo Cong, Bi-min Zhang Newby
Oxalic acid is a diprotic acid and thus has three possible forms in aqueous solution depending on pH, H2C2O4, HC2O4- and C2O42-. At pH > 4.3, the C2O42- ion is predominant in the solution [43]. For AA2024-T3 exposed to solutions with low concentrations of oxalate, aluminium and copper oxide/hydroxide can be expected, while at higher concentrations, oxalate complexes will form, e.g. Al(C2O4)33- and Cu(C2O4)22- [43,44].
Emerging role of organic acids in leaching of valuable metals from refinery-spent hydroprocessing catalysts, and potential techno-economic challenges: A review
Published in Critical Reviews in Environmental Science and Technology, 2021
Ashish Pathak, Mari Vinoba, Richa Kothari
Oxalic acid is one of the most widely used organic acids in metal leaching from spent hydroprocessing catalysts due to its high acidic strength and complexing ability. The pH of 200 mM oxalic acid solution can be as low as 1.50 (Islam, 2008).