Oxalic acid-ammonium oxalate solution

Cobalt(II) oxalate [814-89-1], C0C2O4, is a pink to white crystalline material that absorbs moisture to form the dihydrate. It precipitates as the tetrahydrate on reaction of cobalt salt solutions and oxaUc acid or alkaline oxalates. The material is insoluble in water, but dissolves in acid, ammonium salt solutions, and ammonia solution. It is used in the production of cobalt powders for metallurgy and catalysis, and is a stabilizer for hydrogen cyanide. 

Aquo-pentammino-cobaltic Oxalate, [Co(NH8)5H20]2(C204)3. 1HS0, is prepared from chloro-pentammino-cobaltie chloride. The finely powdered chloride is heated with water and dilute aqueous ammonia, the deep red liquid is filtered, and the filtrate cooled and saturated with oxalic acid. Ammonium oxalate in aqueous solution is then added to complete the precipitation of the salt, and the residue is collected on a filter, washed free from the chloride with water and finally with alcohol.2 The substance does not lose water if kept over concentrated sulphuric acid, but if heated to 100° C. it decomposes. 

Ammonium Tetranitrito - diammino - cobaltate, [Co(XH3)2 (N02)4]NH4, is prepared from cobaltous chloride by mixing an aqueous solution of the salt with aqueous ammonium-chloride solution, sodium nitrite, and ammonia, and oxidising the mixture by passing air through it for several hours. The solution is allowed to stand in air for some days, when crystals gradually separate. These are collected, washed, and reerystallised from water.3 The substance crystallises in brown rhombic prisms. It is decomposed on treatment with potassium hydroxide with evolution of ammonia, and a cold solution reacts with ammonia in presence of ammonium salts, with formation of flavo-dinitro double salts, of which [Co(NH3)4(N02)2][Co(NH3)2(N02)4] is typical. Oxalic acid transforms it into the oxalato-dinitrito-diammino-salt, [Co(NH3)2(N02)2(C204)]NH4. 

Glyoxal, 40 % Solution Glyoxal, 40 % Solution Oxalic Acid Ammonium Oxalate Cyanogen Ferrous Oxalate Cyanogen... 

Classically, wall polysaccharides have been separated into three fractions the pectic polysaccharides, which are extracted by hot water, ammonium oxalate solution, weak acids, or chelating agents the hemi-celluloses, which can be extracted by relatively strong alkali and the residue remaining, which is composed mainly of cellulose. Although these extraction techniques suffer from incomplete and overlapping extraction of the polymers, they are still widely used. 

Heavy Metals and Earths. — On diluting 10 gm. of hydriodic acid with 100 cc. of water and passing hydrogen sulphide gas into a portion of the solution, no colored precipitate should form and, after adding an excess of ammonia water to another portion of the. solution, neither ammonium sulphide nor ammonium oxalate solution should cause a visible change. 

Calcium. — On diluting 20 cc. of hydrochloric acid with 20 cc. of water and adding 50 cc. of ammonia water, followed by a few cc. of ammonium oxalate solution, no precipitate should form on standing two hours. 

Calcium. — Dilute 5 gm. of hydrofluoric acid with 50 cc. of water and add ammonia water in excess, followed by ammonium oxalate solution. An immediate turbidity should not occur. 

Heavy Metals, and Earths. — Dilute 8 cc. of nitric acid with 80 cc. of water, and render slightly alkaline with ammonia water. On adding a few drops of ammonium sulphide and ammonium oxalate solutions, neither a dark color nor a turbidity should result. 

Solubility, Heavy Metals, and Earths. I gin. of pliospho-molybdic acid should completely dissolve in 10 cr. <4 wider. On adding to this solution turn or three drops <4 uumiotiiii water, a yellow precipitate. Forms, which completely ml is-solves on the addition oF 5 ce. of the ammonia water. On now adding to this. solution ammonium sulphide and ammo nium oxalate, solutions, no visible, change should lake place. 

Sulphuric and Oxalic Acids, and Calcium. — Separate 20 cc. portions of the aqueous (1 10) solution of the acid should show no change with barium chloride nor ammonium oxalate solutions nor, when lowered to slight acidity by adding ammonia water, should a precipitate be obtained on adding calcium sulphate solution. 

Iron, Magnesium, and Alkalies. — On warming 2 gm. of calcium sulphate with 10 cc. of hydrochloric acid and 100 cc. of water, a clear solution should result, which, on the addition of 15 cc. of ammonia water and a few drops of ammonium sulphide solution, should not acquire a greenish or dark color. To the solution, no matter whether a precipitate of calcium sulphate has formed or not, add ammonium oxalate solution in slight excess, filter, evaporate the filtrate, and ignite in a platinum dish. There should not remain a residue weighing more than 0.001 gm. 

Calcium. — Digest 20 gm. of copper oxide with a mixture of 5 cc. of nitric acid and 95 cc. of water for about fifteen minutes, shaking frequently filter, precipitate the copper in the filtrate completely by passing hydrogen sulphide gas, and filter again. Evaporate the filtrate on the water-bath to about 20 cc., add ammonia water in excess, filter once more, and to the filtrate add ammonium oxalate solution. No immediate turbidity should be produced. 

Calcium and Alumina. — Dissolve 1 gin. of magnesium carbonate, in 30 cc. of acetic acid (sp. gr. 1.041) and 30 cc. of water. Hoil, add 20 cc. of ammonia water and some ammonium oxalate solution. The liquid should not become turbid within live niinul.es. 

Calcium. — Dissolve 1 gm. of potassium bitartrate in 5 cc. of diluted acetic acid and 25 cc. of water, with the aid of heat. Allow to become perfectly cold, filter, and to the filtrate add a few drops of ammonium oxalate solution. The liquid should show no turbidity within ten minutes. 

Alumina, Calcium, and Heavy Metals. — 2.5 gm. of potassium hydroxide should completely dissolve in 10 cc. of water yielding a clear and colorless solution. Dilute the solution to 100 cc. and add 15 cc. of acetic acid (sp. gr. 1.041), followed by 10 cc. of ammonia water a slight turbidity may form within five minutes, but no flocculent precipitate of aluminum hydroxide should develop. The solution so tested, filtered if necessary, should not exhibit an immediate turbidity on adding ammonium oxalate solution and on the addition of ammonium sulphide solution should acquire at most a slight green color. 

Calcium. — On dissolving 1 gm. of potassium and sodium tartrate in 10 cc. of water, and adding to the solution 5 cc. of dilute acetic acid, and then shaking for a few minutes, a crystalline precipitate forms. On filtering off the latter, diluting the filtrate with an equal volume of water, and then adding 8 to 10 drops of ammonium oxalate solution, no turbidity should develop within one minute. 

Calcium Oxalate. CaCtOj, white precipitate, insoluble in weak acids, but soluble in strong acids, formed by reaction of soluble calcium salt solution and ammonium oxalate solution. Solubility at I8°C 0.0056 g anhydrous salt per liter of saturated solution. 

Calcium chloride White precipitate of calcium oxalate insoluble in dilute acetic acid, oxalic acid, and ammonium oxalate solution soluble in dilute hydrochloric acid and in dilute nitric acid... 

A solution of 2 parts of DL-2-(acetylimino)-3-[2-hydroxy-2-(2-thienyl)ethyl]thiazoline in 16 parts of thionylchloride and 45 parts chloroform is stirred and refluxed for one hour. After cooling the whole is extracted with water. The acid aqueous solution is separated, washed with toluene, alkalized with ammonium hydroxide solution and extracted with chloroform. The extract is dried over magnesium sulfate and evaporated. The oily residue is dissolved in 40 parts boiling 2-propanol. To this warm solution is added a warm solution of an equivalent quantity of oxalic acid dihydrate in 2-propanoL After cooling to room temperature, the precipitated oxalate is filtered off and dried in vacuum, yielding DL-5,6-dihydro-6-(2-thienyl)imidazo[2,l-b]thiazole oxalate MP 192°-193°C. 

A nearly white precipitate of Am and Ca oxalates was obtained while most of the metallic contaminants (e.g., Fe, Cr, Al) remained in solution as stable oxalato complexes. The precipitate was filtered off, dissoved in boiling concentrated nitric acid to destroy the oxalate, neutralized with ammonia to pH = 2.5 to 3, and the Am was extracted from the strongly salted aqueous ammonium nitrate solution by 0.5 M TCMAN/Solvesso. The loaded organic solvent was scrubbed with concentrated ammonium nitrate solution, and the americium was back-extracted with dilute nitric acid, precipitated as the oxalate, and converted into An by calcination at 800°C. Multi-gram amounts of 241 have been prepared with this procedure, with Am purities > 99%. 

Before the americium can be precipitated as the oxalate, the acidity of the solution must be lowered. This cannot be done by the addition of NaOH or KOH as these cations are carried down with the americium oxalate. The acidity adjustment can be made with NH40H with no product contamination, but processing problems resulting from ammonia vapors mixing with nitric acid fumes have to be avoided. Even with the use of efficient traps, some ammonia vapors escape to form solid ammonium nitrate which plugs glovebox exhaust filters plus, ammonium nitrate also slowly sublimes through the entire exhaust system. 

Lime gives a vdute turbidity on addition of saturated ammonium oxalate solution, and sulphates with barium chloride acidified with hydrochloric acid. A useful reagent for nitrites is metaphenylene diamine, 5 grams of which are dissolved in water, acidified with dilute sulphuric acid, and made up to one litre. It may be necessary to previously decolorise the solution with charcoal. If nitrites are present in the water to be tested, on addition of the diamine, a yellow colour is produced, either immediately or upon standing. Starch-iodide solution acidified with dilute sulphuric acid may also be used, the characteristic blue colour of the starch-iodine complex indicating nitrites, but this test is not altogether satisfactory. 

If the water is first concentrated to one-fiftieth of its bulk, tests may be carried out for magnesia and phosphates. The former is precipitated as magnesium ammonium phosphate on standing for some twenty-four hours after addition of sodium phosphate solution to the water rendered alkaline with ammonium hydroxide in the presence of chloride. It is assumed that any lime has previously been removed with ammonium oxalate. Phosphates are precipitated as yellow phosphomolybdate on adding excess of ammonium molybdate solution to the water acidified with nitric acid, and warming. 

Alkalies or Magnesium Dissolve 500 mg of sample in 30 mL of water and 15 mL of 2.7 N hydrochloric acid. Heat the solution, and boil for 1 min. Rapidly add 40 mL of oxalic acid TS, and stir vigorously. Add 2 drops of methyl red TS, and neutralize the solution with 6 N ammonium hydroxide to precipitate the calcium completely. Heat the mixture on a steam bath for 1 h, cool, dilute to 100 mL with water, mix well, and filter. Add 0.5 mL of sulfuric acid to 50 mL of the filtrate, then evaporate to dryness, and ignite to constant weight in a tared platinum crucible at 800° 25°. 

Calcium chloride solution white, crystalline precipitate of calcium oxalate from neutral solutions, insoluble in dilute acetic acid, oxalic acid, and in ammonium oxalate solution, but soluble in dilute hydrochloric acid and in dilute nitric acid. It is the most insoluble of all oxalates (0 0067 g t 1 at 13°) and is even precipitated by calcium sulphate solution and acetic acid. Barium chloride solution similarly gives a white precipitate of barium oxalate sparingly soluble in water (0 016 g t-1 at 8°), but soluble in solutions of acetic and of oxalic acids. 

Oxalate in the presence of fluoride Both calcium fluoride and calcium oxalate are precipitated by ammonium oxalate solution in the presence of dilute acetic acid. The fluoride may be identified in the usual manner with concentrated sulphuric acid or as described below. The oxalate is most simply detected by dissolving a portion of the precipitate in hot dilute sulphuric acid and then adding a few drops of a very dilute solution of potassium permanganate. The latter will be decolourized if an oxalate is present. 

Oxalic acid or ammonium oxalate solution no precipitate (difference from thorium, zirconium, and cerium). 

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