Urea nitrate oxalate

Urea nitrate and oxalate. Prepare a concentrated aqueous solution of urea, (a) To one portion, add a few drops of cone. HNO the white... 

Urea oxalate—2CON3H4,HjCi04—separates as a fine, crystalline powder from mixed aqueous solutions of urea and oxalic acid of sufficient concentration. It is acid in taste and reaction, less soluble in cold HjO than the nitrate, and less soluble in the presence of an excess of oxalic acid than in pure HjO. Its solution may be evaporated at the temperature of the water-bath without suffering decomposition. 

Thomson says Fourcroy and Vauquelin do not mention Cruickshank in their paper of 1808 (see above), but Fourcroy added copious notes to the French translation of Rollo s work, and must therefore of necessity have been acquainted with that book . Fourcroy repeatedly spoke of the long series of researches made by himself and Vauquelin on urine. Fourcroy later mentioned Cruickshank s discoveries (particularly of urea nitrate), but says he and Vauquelin made them bien avant le chimiste anglais . Fourcroy and Vauquelin say they had discovered urea before they got to know of Rollo s book from a long notice of it in the Bibliotheque Britannique. Berzelius was the first to obtain pure urea by way of the oxalate but the work was not known till the English translation of his book appeared. Berzelius later used nitric acid, saying that urea nitrate was first noticed by Cruickshank. Urea oxalate was investigated by Prout. ... 

Urea is a monacldic base, and forms a characteristic nitrate, C0(NH2)2,HN03, and oxalate, 2CO(NH2)2,(COOH)2,2H20. To prepare the nitrate, dissolve i g. of urea in about 5 ml. of... 

Urea possesses negligible basic properties (Kb = 1.5 x 10 l4), is soluble in water and its hydrolysis rate can be easily controlled. It hydrolyses rapidly at 90-100 °C, and hydrolysis can be quickly terminated at a desired pH by cooling the reaction mixture to room temperature. The use of a hydrolytic reagent alone does not result in the formation of a compact precipitate the physical character of the precipitate will be very much affected by the presence of certain anions. Thus in the precipitation of aluminium by the urea process, a dense precipitate is obtained in the presence of succinate, sulphate, formate, oxalate, and benzoate ions, but not in the presence of chloride, chlorate, perchlorate, nitrate, sulphate, chromate, and acetate ions. The preferred anion for the precipitation of aluminium is succinate. It would appear that the main function of the suitable anion is the formation of a basic salt which seems responsible for the production of a compact precipitate. The pH of the initial solution must be appropriately adjusted. 

Magnesium nitrate, Tin(ll) fluoride, 4693 Manganese(lV) oxide, Calcium hydride, 4705 Molybdenum(VI) oxide, Graphite, 4717 Nitric acid, Formaldehyde, 4436 Nitric acid, Formic acid, 4436 Nitric acid, Formic acid. Urea, 4436 Nitric acid, Metal thiocyanate, 4436 Oxalic acid, Urea, 0725 Ozone, Acetylene, 4846... 

Synonym Ammonia Water Amfbnioformaldehyde Ammonium Acetate Ammonium Acid Fluoride Ammonium Amidosulfonate Ammonium Amidosulphate Ammonium Benzoate Ammonium Bicarbonate Ammonium Bichromate Ammonium Bifluoride Ammonium Carbonate Ammonium Chloride Ammonium Citrate Ammonium Citrate, Dibasic Ammonium Decaborate Octahydrate Ammonium Dichromate Ammonium Disulfate-Nickelate (II) Ammonium Ferric Citrate Ammonium Ferric Oxalate Trihydrate Ammonium Ferrous Sulfate Ammonium Fluoride Ammonium Fluosilicate Ammonium Formate Ammonium Gluconate Ammonium Hydrogen Carbonate Ammonium Hydrogen Fluoride Ammonium Hydrogen Sulfide Solution Ammonium Hydroxide Ammonium Hypo Ammonium Hyposulfite Ammonium Iodide Ammonium Iron Sulfate Ammonium Lactate Ammonium Lactate Syrup Ammonium Lauryl Sulfate Ammonium Molybdate Ammonium Muriate Ammonium Nickel Sulfate Ammonium Nitrate Ammonium Nitrate-Urea Solution Ammonium Oleate... 

Urea resembles the amines in certain of its reactions, as the NH2CO group which is in combination with the second NH2 group in urea, NH2CO.NH2, is more positive than the acyl radicals. It forms salts with strong acids The nitrate CO(NH2)2.-HNO3 and oxalate 2CO(NH2)2.(COON)2, crystallize well. Urea, like methylamine, reacts with acetyl chloride and acetyl urea is formed, CH3CO.NH.CO.NH2. A number of such compounds, which are called ureides, are known. 

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