Sodium—continued nitrite

Red Sodium Cobalti-nitrite, 2Na2O.Co203.4N203.—To obtain this salt, nitrous acid is added to a suspension of cobalt carbonate in the requisite quantity of sodium nitrite solution until a reddish brown colour is attained. The liquor is evaporated by exposure over sulphuric acid, leaving a reddish brown crystalline powder of the above composition.4 Alcohol does not precipitate this salt from its aqueous solution, neither is a precipitate obtained with a soluble potassium salt. In both these features, therefore, the red sodium cobalti-nitrite differs from the yellow salt already described. Continued treatment with nitrous oxide converts the red salt into the yellow derivative. 

Dissolve 2 g. of anhydrous sodium carbonate in 50 ml. of water contained in a 400 ml. beaker and add 7 g. of finely powdered crystalline sulphanilic acid (2H2O), warming the mixture gently in order to obtain a clear solution. Add a solution of 2 2 g. of sodium nitrite in 10 ml. of water and then cool the mixture in ice-water until the temperature has fallen to 5°. Now add very slowly (drop by drop) with continual stirring a solution of 8 ml. of concentrated hydrochloric acid in 15 ml. of water do not allow the temperature to rise above 10°. When all the acid has been added, allow the solution to stand in ice-water for 15 minutes to ensure complete diazotisation during this period fine crystals of the internal salt separate from the pink solution. Dissolve 4 ml. of dimethylaniline in a mixture of 4 ml. of concentrated hydrochloric acid and 10 ml. of water, cool the solution in ice-water, and add it slowly to the cold well-stirred diazo solution a pale red coloration is developed. Allow the mixture to stand for 5 minutes and then add slowly with stirring aqueous... 

Fit a three necked 250 ml. flask with a central rubber-sleeved or mercury-sealed stirrer, c/. Fig. 23(c), p. 45, where only two necks are shown, and with a thermometer the bulb of which reaches as near the bottom of the flask as the stirrer allows the third neck will carry at first a dropping-funnel and later a reflux condenser. Place 20 g. (19-5 ml.) of ethyl acetoacetate and 45 ml. of glacial acetic acid in the flask and by ice-water cooling adjust the temperature of the stirred mixture to 5 -7° maintain this temperature whilst adding a solution of 5 4 g. of sodium nitrite in 8 ml. of water slowly from the dropping-funnel during 15 minutes. Continue the stirring for 20-30 minutes, and then... 

Add 101 g. (55 ml.) of concentrated sulphuric acid cautiously to 75 ml. of water contained in a 1 htre beaker, and introduce 35 g. of finely-powdered wi-nitroaniline (Section IV,44). Add 100-150 g. of finely-crushed ice and stir until the m-nitroaniUne has been converted into the sulphate and a homogeneous paste results. Cool to 0-5° by immersion of the beaker in a freezing mixture, stir mechanically, and add a cold solution of 18 g. of sodium nitrite in 40 ml. of water over a period of 10 minutes until a permanent colour is immediately given to potassium iodide - starch paper do not allow the temperature to rise above 5-7° during the diazotisation. Continue the stirring for 5-10 minutes and allow to stand for 5 minutes some m-nitrophenjddiazonium sulphate may separate. Decant the supernatant Uquid from the solid as far as possible. 

Dissolve 10 g. of p-nitroaniline (Section IV,51) in a mixture of 21 ml. of concentrated hydrochloric acid and an equal volume of water, and cool rapidly to 0° in order to obtain the hydrochloride of the base in a fine state of division. Diazotise in the usual way (see Section IV,68) by the gradual addition of a solution of 6 0 g. of sodium nitrite in 12 ml. of water. Continue the stirring for a few minutes, filter the solution rapidly, and add it from a separatory funnel to an ice-cold solution of 41 g. of sodium sulphite (90 per cent. NajS03,7H20) in 100 ml. of water containing... 

Chlorodiphenyl. Diazotise 32 g. of o-chloroaniline (Section IV,34) in the presence of 40 ml. of concentrated hydrochloric acid and 22 -5 ml. of water in the usual manner (compare Section IV,61) with concentrated sodium nitrite solution. Transfer the cold, filtered diazonium solution to a 1 5 htre bolt-head flask surrounded by ice water, introduce 500 ml. of cold benzene, stir vigorously, and add a solution of 80 g. of sodium acetate trihydrate in 200 ml. of water dropwise, maintaining the temperature at 5-10°. Continue the stirring for 48 hours after the first 3 hours, allow the reaction to proceed at room temperature. Separate the benzene layer, wash it with water, and remove the benzene by distillation at atmospheric pressure distil the residue under reduced pressure and collect the 2-chlorodiphenyl at 150-155°/10 mm. The yield is 18 g. Recrystalliae from aqueous ethanol m.p. 34°. 

Heat a mixture of 49 g. of acetylmethylurea (3) and 50 ml. of concentrated hydrochloric acid, with hand stirring, on a steam bath until it is apparent that no more solid is dissolving (4) and continue the heating for 3—4 minutes longer the total time of heating on the steam bath should be 8-12 minutes. Dilute the solution with 50 ml. of water and cool below 10° in an ice bath. Run in slowly and with stirring a cold saturated solution of 38 g. of A.R. sodium nitrite in 55 ml. of water below the level of the liquid. Keep the mixture in the ice bath for 5-10 minutes, filter the solid at the pump and wash it with 8-10 ml. of ice-cold water. Dry the nitrosomethylurea (pale yellow crystals) in the air or in a. vacuum desiccator (5) the yield is 34 g., m.p. 12 124°. 

The trend in architectural applications has been towards more matt finishes, and the sodium hydroxide-based etchants used frequently contain additives such as sodium nitrate or nitrite or sodium fluoride. Chelating agents such as gluconates, heptonates or sorbitol are added to complex the aluminium produced, and other additives such as sulphides may be present in the etchant to complex zinc dissolved from the alloy, and allow it to be used continuously without dumping ... 

A. o-Bromobenzenediazonium hexafluorophosphate. A solution of 95 ml. of 12N hydrocMoric acid in 650 ml. of water is added with stirring to 60 g. of o-bromoaniline (0.35 mole Note 1) in a 2-1. three-necked flask equipped with stirrer and thermometer. Solution is effected by heating the mixture on a steam bath (Note 2). A solution of 29 g. (0.42 mole) of sodium nitrite in 75 ml. of water is added with stirring while the mixture is maintained at — 5° to —10° by means of a bath of ice and salt or of dry ice and acetone. At the end of the addition there is an excess of nitrous acid, which can be detected with starch iodide paper. Seventy-four milliliters (134 g., 0.60 mole) of 65% hexafluorophosphoric acid (Note 3) is added in one portion, with vigorous stirring, to the cold solution of the diazonium salt. Cooling and slow stirring are continued for an additional 30 minutes, and the precipitated diazonium hexafluorophosphate is then collected on a Bilchner funnel. The diazonium salt is washed on the funnel with 300 ml. of cold water and with a solution of 80 ml. of methanol in 320 ml. 

N - Nitrosomethylaniline (methylphenylnitrosamine). Place 53-5 g. of pure commercial monomethylaniline, 72-5 ml. of concentrated hydrochloric acid and 200 g. of crushed ice in a 500 ml. beaker equipped with a mechanical stirrer. Support a separatory funnel with a long bent stem (as in Fig. Ill, 35,1) containing a solution of 36 g. of sodium nitrite in 125 ml. of water over the beaker. Stir the solution and run in the sodium nitrite solution during 10 minutes do not allow the temperature to rise above 10° and add more ice if necessary. Continue the stirring for a further hour. Separate the oily layer, wash it once with 50 ml. of water, and dry it with anhydrous magnesium or calcium sulphate. Distil under reduced pressure from a 100 ml. Claisen flask. Collect the iV-nitrosomethylaniline (a pale yellow liquid) at 120°/13 mm. The yield is about 65 g. 

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