Oxalic acid Salts

Oxalic Acid, Salts of, Bertholet (Ref 2) in 1883 noticed that some salts of oxalic add, eg mercuric or silver, have the properties of primary expls. According to Urbadski (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... 

Scheme 7 Esterification of 1-Aminoalkylphosphonic Acids with Triethyl Orthoformate To Give Diethyl 1-Aminoalkylphosphonate Oxalic Acid Salts 251...

Oxalic acid salts can be decomposed in a manner analogous to oxalic acid.6... 

This drawback is not easily surmountable in certain cases, even if an accurate stoichiometric dosage of the reactants is made. Some possible solutions to this problem can be found in Sec. A.2 and A.4, dealing with amine and preformed reagents, respectively. The synthesis of Mannich bases containing a secondary amino group may be also elegantly performed by allowing the primary amine to react as an oxalic acid salt. "... 

Oxalic acid salts can be obtained from some plants, such as asparagus. 

Oxalic acid salts can be obtained directly from some plants. They can also be obtained by passing C02 through Na or K at 300-350°C and high pressure. 

Amiton, 0,0-diethyl-S-(2-diethylaminoethyl) phosphorothioate (65) is the sole representative of practical importance of this type of insecticide (Ghosh and Newman. 1955). It has a basic character because of its tertiary nitrogen atom, and forms water-soluble salts with acids. Its oxalic acid salt was introduced under the trade name Tetram. ... 

The decomposition reactions of oxalic acid salts are entirely analogous to those of the free acid. In alkaline solution the oxidation proceeds more rapidly than in neutral solution because of the better conductivity of the alkalies. 

Acetic acid (acidum aceticum) with lUPAC name ethanoic acid is used as an everyday food additive. Citric acid, which is also a natural product, is a polyfunc-tional compound with three carboxylic and one OH group. A molecule of the simple oxalic acid consists of only two carboxylic groups. Oxalic acid salts are frequently present in kidney stones. 

Unfavorable combinations and/or choice of chalk (natural calcite, precipitated cal-cite/aragonite) may cause discoloration in the form of yellow spots in chalk-filled PVC [685]. The formation of yellow spots is attributed to oxalic acid (salts) detected by FTIR-spectroscopy. The creation of oxalic acid (salts) depends on the presence of calcium carbonate. The type of filler and stabilization determine the rate of calcium oxalate creation [685]. 

Crystallizes from water in large colourless prisms containing 2H2O. It is poisonous, causing paralysis of the nervous system m.p. 101 C (hydrate), 189°C (anhydrous), sublimes 157°C. It occurs as the free acid in beet leaves, and as potassium hydrogen oxalate in wood sorrel and rhubarb. Commercially, oxalic acid is made from sodium methanoate. This is obtained from anhydrous NaOH with CO at 150-200°C and 7-10 atm. At lower pressure sodium oxalate formed from the sodium salt the acid is readily liberated by sulphuric acid. Oxalic acid is also obtained as a by-product in the manufacture of citric acid and by the oxidation of carbohydrates with nitric acid in presence of V2O5. 

The b.p. under diminished pressure has been given as 80-81°/18 mm. To obtain a very pure sample of the amine, dissolve 1 part (by weight) of the above product with a sohitiuii of 1-04 parts of crystallised oxalic acid in 8 parts of hot water, add a little deculeiirisiiig carbon, and tilter. The liltered solution deposits crystals uf the acid oxalate about o g. of tliis salt remains in each 100 ml. of... 

The only reported industrial appHcation for Fep2 is its use in mst removal solutions based on oxalic acid (6). The anhydrous salt is commercially available in 100 g to 5 kg lots from Advance Research Chemicals, Aldrich Chemicals, Cerac, Johnson/Matthey, PCR, and other suppHers in the United States. As of 1993, the prices varied between 500 to 700/kg. 

Aqueous emulsion polymerization is carried out using a fluorinated emulsifier, a chain-transfer agent to control molecular weight, and dispersion stabilizers such as manganic acid salts and ammonium oxalate (13,14). 

When a carrier is impregnated with a solution, where the catalyst deposits will depend on the rate of diffusion and the rate of adsorption on the carrier. Many studies have been made of Pt deposition from chloroplatinic acid (HgPtClg) with a variety of acids and salts as coim-pregnants. HCl results in uniform deposition of Pt. Citric or oxalic acid drive the Pt to the interior. HF coimpregnant produces an egg white profile. Photographs show such varied distributions in a single pellet. 

Dry air is blown through the solution to remove the excess of ammonia, and the solution is then dissolved in its own volume of absolute alcohol. A sample of this solution is titrated with standard oxalic acid, litmus being used as an outside indicator (Note 3). The amount of oxalic acid (Note 4) necessary to form the acid salt is placed in a large evaporating dish and dissolved in 4 1. of 95 per cent alcohol. The amine solution is then slowly run into the acid with constant stirring. During the addition of the last half of the amine solution, the container must be cooled in order to avoid the formation of the neutral oxalate,... 

The end point to litmus occurs when the neutral salt is formed. As the acid salt is desired, twice the amount of oxalic acid calculated above is used. This is usually between 230 and 260 g. 

Potassium tetraoxaiate (2H2O) [oxalic acid hemipotassium salt] [6100-20-5 (2H2O) 127-96-8 (anhydr)] M 254.2. Crystd from water below 50°. Dried below 60° at atmospheric pressure. 

If very pure amine is desired the product described above is dissolved with 1.04 parts of crystalline oxalic acid in eight parts of hot water. After clarification with Norite, the filtered solution on cooling deposits crystals of the acid oxalate. About 5 g. of the salt remains in each 100 cc. of the mother liquor most of this can be obtained by evaporation and further crystallization. The amine is liberated from the pure oxalate with potassium hydroxide, distilled with steam, and purified as described above. When a known amount of amine is desired in water solution (as for optical resolution) a weighed amount of the (anhydrous) oxalate is decomposed and the amine is distilled quantitatively with steam. 

Oxalic acid Beneficial reduces effects of CO2, salt water, dilute acetic acid... 

Chemical Designations - Synonyms Ammonium Oxalate Hydrate Diammonium Oxalate Oxalic Acid, Diammonium Salt Chemical Formula (NH,)2C204 H20. 

Chemical Designations - Synonyms Ferrous oxalate dihydrate, Ferrox, Iron protoxalate. Oxalic acid (ferrous salt) Chemical Eormula FeC204 2H20. 

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