Water neutralisation

W. Luo, M.N. Karim, A.J. Morris and E.B. Martin, Control relevant identification of a pH waste water neutralisation process using adaptive radial basis function networks. Computers Chem. Eng., 20(1996)S1017... 

To a solution of 3p-acetoxy-17-(3-pyridyl)androsta-5,16-diene (4.90 g, 12.5 mmol) in methanol (50 ml) was added an aqueous solution of sodium hydroxide (10% w/v, 10 ml) and the mixture heated, with stirring, on an oil bath at 80°C for 5 min, then allowed to cool. The mixture was poured into water, neutralised with hydrochloric acid (1 M), rebasified with saturated sodium bicarbonate solution, and extracted with hot toluene. The toluene extracts were combined, dried (Na2C03), and concentrated. Chromatography, on elution with toluene-diethyl ether (2 1) afforded the 17-(3-pyridyl)androsta-5,16-dien-3p-ol (3.45 g, 79%) which crystallised from toluene, m.p. 228-229°C. 

After the trimethylchlorosilane has been loaded, the mixture is agitated for 1 more hour. Then the agitator is switched off. The mixture splits. The bottom layer (hydrochloric acid) is poured into collector 5, and the top layer (the product of hydrolysis) is sent into apparatus 6, which is also filled with 15% (weight) of sulfuric acid. The mixture is agitated at room temperature for 1 hour. Then, the apparatus is filled with water to dilute the acid, and the mixture is split. The bottom layer is poured off the product remaining in apparatus 6 is flushed with water, neutralised, dried and sent to nutsch filter 7. The filtrate is sent into collector 8 and then to tank 9... 

Triphenylsilicol trisulphonic acid, (CgH4S03H)3Si(0H), is made by gently warming one part of the above silxcol with six parts of fuming sulphuric acid. When it is all dissolved, the solution is poured into cold water, neutralised with barium carbonate, then gently warmed and filtered from barium sulphate. Evaporation of the filtrate yields the barium salt in white flakes. 

The residue in the can should be dissolved in water, neutralised using dilute hydrochloric acid and poured down the drain. 

Sodium Chloride can be determined in 100 c.c. of the glycerine by adding a little water, neutralised with sodium carbonate, and then titrated with a deci-normal solution of silver nitrate, using potassium chromate as indicator. 

Tetraphenylarsonium chloride hydrate [507-28-8] M 418.8, m 258-260", 261-263". A nentralised aqueous solution is evaporated to dryness. The residue is extracted into absolnte EtOH, evaporated to a small volnme and precipitated by addition of absolute Et20. It is again dissolved in a small volume of absolute EtOH or ethyl acetate and re-precipitated with Et20. Alternatively, it is purified by adding cone HCl to precipitate the chloride dihydrate. Redissolve in water, neutralise with Na2C03 and evaporate to dryness. The residne is extracted with... 

Commence simultaneous acid and caustic regeneration 6% HCl solution up flow through the cation bed for 30 min and 4% NaOH solution at 43—49°C downflow through the anion bed for 60 min. The two streams flow out to waste-water neutralisation tank through the interface collector imbedded in the inert resin layer. 

SPILLAGE LEAK Sweep up and collect spillage into suitable sealable container. Protective clothing, see above. Residual amounts carefully with water, neutralise with dilute acid, flush away with large volumes water. Clothing see above. ... 

Medium 1 Medium 2 acidic waste water waste water neutralised with NaOH and lime milk ... 

The organic chemical industry uses NaOH for saponification reactions, production of anionic intermediates, etherification and esterification, basic catalysis, for waste gas scrubbing and for waste water neutralisation. 

To a mixture of 50 ml of water, 3 ml of dilute ammonia solution and 6 ml of 10 per cent ammonium nitrate solution add 0 8 g of sample, warm on a water-bath for fiye minutes and add 25 ml of 01N silver nitrate. Warm for fifteen minutes, shaking frequently, cool, dilute to 200 ml with water and allow to stand for sixteen hours. Filter, wash the residue with water, neutralise the combined filtrate and w-ashings to litmus paper with concentrated nitric acid and add 3 ml of the acid in excess. Titrate the excess silyer nitrate with 0-1N ammonium thiocyanate using ferric alum as indicator. 1 ml 0 1N silyer nitrate = 0 02146 g C H OaN Cl. 

For estimation dissolve about 15 g in water, neutralise to methyl orange, add glycerol or mannitol and titrate with 0 5N alkali to phenolphthalein or phenol violet. 1 ml 0 5N = 0 04768 g borax. 

To about 0-4 g add 25 ml of 95 per cent ethanol and warm on a water-bath until dissolved. Cool, add 10 ml of N alcoholic potassium hydroxide made with 95 per cent ethanol, swirl gently and allow to stand for ten minutes. Dilute to 150 ml with water, neutralise with dilute nitric acid and add 10 ml in excess, followed by 50 ml of 0 1 N silver nitrate. Complete by Volhard s method (see under Halogen Acids, p. 290). Carry out a blank determination on about the same amount of sample as above (10 mg), adding the same volume of all reagents in the order, dilute nitric acid, ethanol, potassium hydroxide solution and silver nitrate. 1 ml 0-1N 0 009695 g of CgHgCle. Alternatively the hydrolysed chlorine may be determined electrometrically. 

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