Salts of oxalic acid

As early as 1883 Berthelot [75] noticed that some salts of oxalic acid (e.g. mercuric or silver oxalates) have the properties of primary explosives. 

This group of initiators has no practical application. Nevertheless it is interesting from the theoretical point of view, due chiefly to the fact that the general equation for the decomposition of oxalates is  

Thus it is similar to the decomposition of azides. There have been several papers on silver oxalate — Ag2C204. Macdonald and Hinshelwood [76] confirmed the Berthelot equation, according to which the only products of decomposition of silver oxalate are metallic silver and C02. 

Benton and Cunningham [77] found that the rate of thermal decomposition of silver oxalate may be increased by previously exposing it to ultra-violet radiation. 

During the thermal decomposition of silver oxalate, fragments of metallic silver are formed. This has been confirmed by conductivity measurements (Macdonald and Sandison [78]) or by X-ray examination (Griffith [79]). 

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Oxalic acid occurs in high concentrations in pineapple and rhubarb, among other plants, and is responsible for the sharpness of the fresh fruits. Ingestion of too much oxalic acid can cause gastroenteritis, commonly recognized as a stomach ache. A salt of oxalic acid, calcium oxalate, is the stuff of kidney stones. 

Water insolubility and resistance to hydrolysis water solubility could lead to more reaction in the aqueous phase and wall fouling. Other expedients to reduce aqueous phase reactions include use of a water-soluble free-radical scavenger or a chelating agent to minimize redox reactions in the aqueous phase. (Such water-soluble chelating agents include salts of oxalic acid and ethylene diamine tetraacetic acid.)... 

Oxalic Acid, Salts of. Bertholet (Ref 2) in 1883 noticed that some salts of oxalic acid, eg mercuric or silver, have the properties of primary expls. According to Urbaifski (Ref 14), although they have no practical application as initiators, it is interesting from a theoretical point of view, due chiefly to the fact that the general equation for the decompn of oxalates is + Cgas- Thus it is simUar to... 

Commercial Preparation.—The commercial method for preparing oxalic acid, up to a few years ago, was by the oxidation of sawdust or sugar. In practice sawdust was oxidized by heating it with fused alkali by which process the alkali salt of oxalic acid was obtained. When sugar, or similar organic substances, like cellulose, are oxidized the reaction may be illustrated by the oxidation of the hexa-hydroxy hexane, or mannitol, as follows ... 

Potassium Tetroxalate, KOOC—COOH HOOC—COOH 2H2O.— This salt is also known commercially as salt of sorrel. The salts of oxalic acid with the alkali metals are more soluble in water than the free acid itself. Both the salts and the free acid dissolve iron rust and iron inks and are often used for the purpose of removing such substances from cloth. 

Another reaction by which both oxamic acid and oxamide may be prepared is by heating the ammonium salt of oxalic acid. The reaction takes place in two steps. Firsts by the loss of one molecule of water the ammonium salt of oxamic acid is formed. Second, by the loss of another molecule of water, this is converted into oxamide, as follows ... 

It is a white solid used in removal of certain kinds of stains, in removing calcium ions from solutions, and in tanning leather. It occurs naturally and is toxic. The potassium and calcium salts of oxalic acid are found naturally in cabbage, spinach, and rhubarb leaves, and are also found in the bark of some species of eucalyptus trees. The metabolism of sugar by many species of mold results in the production of oxalic acid. Ingestion of large amounts can cause kidney damage, convulsions, and death. 

Other slyphnates Lead dinitroresorcinale Nitrosophcnol salts Nitraminc salts Salts of metazonic acid Salts of oxalic acid Peroxides... 

Boldyrev et al. [46], from quantum mechanical calculations of bond strengths in the oxalate anion, and from observations [38] of the decomposition of this species in potassium bromide matrices, concluded that the most probable controlling step in the breakdown of the oxalate ion is rupture of the C-C bond. This model is (again) based on the observation that the magnitudes of the activation energies for decompositions of many metal salts of oxalic acid are comparable. This model was successfiilly applied [46,68] to the decompositions of many oxalates, with the possible exception of silver oxalate where the strengths of the C-C and Ag-0 bonds are similar. 

Calculate the concentrations of H3O+, OH-, HSe04-, and Se04 - in 0.12 M H2Se04, selenic acid, solution. Some kidney stones are crystalline deposits of calcium oxalate, a salt of oxalic acid, (COOH)2. Calculate the concentrations of H3O+, OH-, COOCOOH-, and (C0Q-)2 in 0.12 M (COOH)2. Compare the concentrations with those obtained in Exercise 62. How can you explain the difference between the concentrations of... 

Oxalic acid is a white, crystalline solid. Its melting point is 189 °C though it sublimes at 157 °C. It is poisonous, the calcium salt of oxalic acid precipitates in the... 

When the acid ammonium salt of oxalic acid is heated, water is lost, as in the case of the neutral salt, and a compound called oxamic add is obtained —... 

M.K. Chantooni, Jr. and I.M. Kolthoff, Acid-base equilibria in methanol, acetonitrile, and dimethyl sulfoxide in acids and salts of oxalic acid and homologs, fumaric and o-phthalic acids. Transfer activity coefficients of acids and ions, J. Phys. Chem. 79 (1975), pp. 1176-1182. 

The name oxalic acid is derived from one of its sources in the biological world, namely, plants of the genus Oxalis, one of which is rhubarb. Oxalic acid also occurs in human and animal urine, and calcium oxalate (the calcium salt of oxalic acid) is a major component of kidney stones. Adipic acid is one of the two monomers required for the synthesis of the polymer nylon 66. The U.S. chemical industry produces approximately 1.8 billion pounds of adipic acid annually, solely for the synthesis of nylon 66 (Section 16.4A). 

The monopotassium salt of oxalic acid is present in certain leafy vegetables, including rhubarb. Both oxalic acid and its salts are poisonous in high concentrations. Draw a structural formula of monopotassium oxalate. 

Appreciable concentrations of the potassium and calcium salts of oxalic acid, (COOHjj, are found in many leafy green plants, such as rhubarb and spinach, (a) Calculate the molar concentrations of HOOCCO2, (C02)l, H3O+, and OH" in 0.15 M (COOH)2(aq). (b) Calculate the pH of a solution of 0.15 M potassium hydrogenoxalate. 

Oxalic acid crystallized with five water molecules is used in the standardization of oxalie aeid. It is eommercially available in a state of guaranteed purity. Sodium, potassium, and ammonium salts of oxalic acid are also used. The corresponding half-redox reaetion is... 

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