Ammonia-water distillation

Figure 8-44. Ponchon type diagram for ammonia-water distillation.

The ammonia-water absorption system was extensively used until the fifties when the LiBr-water combination became popular. Figure 11-103 shows a simplified ammonia-water absorption cycle. The refrigerant is ammonia, and the absorbent is dilute aqueous solution of ammonia. Ammonia-water systems differ from water-lithium bromide equipment to accommodate major differences Water (here absorbent) is also volatile, so the regeneration of weak water solution to strong water solution is a fractional distillation. Different refrigerant (ammonia) causes different, much higher pressures about 1100-2100 kPa absolute in condenser. 

Cellulose for chromatography is purified by sequential washing with chloroform, ethanol, water, ethanol, chloroform and acetone. More extensive purification uses aqueous ammonia, water, hydrochloric acid, water, acetone and diethyl ether, followed by drying in a vacuum. Trace metals can be removed from filter paper by washing for several hours with O.IM oxalic or citric acid, followed by repeated washing with distilled water. 

The checkers removed the ammonia by distillation (water aspirator). 

B) Preparation of S-Trifluoromethyl-2,4-Disulfamylaniline—The 5-trifluoromethylaniline-2,4-disulfonyl chloride obtained in step (A) is taken up in ether and the ether solution dried with magnesium sulfate. The ether is removed from the solution by distillation, the residue is cooled to 0°C, and 60 ml of ice-cooled, concentrated ammonia water is added while stirring. The solution is then heated for one hour on a steam bath and evaporated... 

The following is an alternative method of preparation. Dissolve lOOg mercury(II) iodide and 70g potassium iodide in 100mL ammonia-free water. Add slowly, and with stirring, to a cooled solution of 160 g sodium hydroxide pellets (or 224 g potassium hydroxide)in 700 mL ammonia-free water, and dilute to 1 L with ammonia-free distilled water. Allow the precipitate to settle, preferably for a few days, before using the pale yellow supernatant liquid. 

The advantage of the H — x chart lies in the fact that the heat quantities required for the distillation are clearly indicated. Thus, the higher the reflux ratio the more heat must be removed per mole of product, and point N rises. This immediately shows that both qc and Qb are increased. The use of this method is illustrated by considering the separation of ammonia from an ammonia-water mixture, as occurs in the ammonia absorption unit for refrigeration. 

Waste water Distillation of acidified solution, reacted with ammonia, Y-chloro-succimmide, and sodium nitro-prusside at basic pH Spectrophotometric <0.3 mg/L 96.7% at 3 mg/L Amlatheetal. 1987... 

A 3 1 molar ratio of ammonia and carbon dioxide (excess ammonia) are heated in the autoclave for 2 hr at 190°C, and 1500-3000 psi. The mixture formed is approximately 35% urea, 8% ammonium carbamate, 10% water, and 47% ammonia. It is cooled and the ammonia is distilled at 60 °C. The residue from the ammonia still enters a crystallizer at 15°C. More ammonia is removed by vacuum. The resulting slurry is centrifuged to get solid urea. All excess nitrogenous materials from the liquid are combined and processed into liquid fertilizer, which contains a mixture of all these materials. 

Ammonium-N standard solution, 140 pg mM nitrogen - weigh 0.661 g ammonium sulphate (dried at 105°C for 1 h and cooled in a desiccator) into a 100-ml beaker and dissolve in ammonia-free water (distil deionized water acidified with sulphuric acid), transfer with washings to a 1-1 volumetric flask and make up to the mark with the ammonia-free water and mix. This should be stored in a refrigerator, but a quantity allowed to warm to room temperature in a stoppered container before use. 

Ammoniaeal Liquor or Gas Liquor. Impure ammonia water obtained as a by-product in the distillation of coal, tar, bones, etc... 

In 1773 it occurred to Priestley to apply the method he had used to obtain his marine acid air to see whether an alkaline air might be obtained from substances containing volatile alkali. He procured some volatile spirit of sal ammoniac (that is, ammonia water), placed it in a thin phial and heated it with a candle. A great quantity of vapor was discharged, which, collected over mercury, continued in the form of a transparent and permanent air, not at all condensed by cold. Sal volatile (that is, ammonium carbonate) and other salts obtained by the distillation of sal volatile with fixed alkalies, were tried but found to yield much fixed air also, so that he eventually used the mixture then customary for preparing the volatile spirit of sal ammoniac, viz., one part of sal ammoniac with three parts of slaked lime, which furnished him a large and easily controlled supply of pure alkaline air. ... 

Distillation of Ammonium Bicarbonate Solutions. Vapor-liquid equilibrium data for ammonium bicarbonate solutions at the boil are apparently not available in the literature. The data in the literature, however, do indicate that when the temperature of such a solution is increased, or the pressure on it decreased, the gas that is evolved is predominantly carbon dioxide. Thus, it appears that such a distillation would be two consecutive processes first, a steam stripping of the carbon dioxide in the solution, followed by a distillation of ammonia from an ammonia-water mixture containing perhaps some carbon dioxide. Possibly the ammonia, carbon dioxide, and water in the distillate product would recombine completely in the condenser to form an ammonium bicarbonate solution. Perhaps an absorption tower would be necessary to effect the recombination. 

For nitrogen, dilute 25 ml. with about 100 ml. of water, add excess sodium hydroxide, arid determine the ammonia by distillation into standard acid. 

Ammonia-free distilled water pass distilled water through a strongly acidic cation-exchange resin. Alternatively, add a few drops of cone. H2S04 and redistill. 

Use ammonia-free distilled water in the preparation of all the reagents and standards. 

The refining area has five steps 1) ammonia removal, 2) NaCl concentration and removal, 3) hydrazine-water distillation to reach azeotropic concentration, 4) extractive distillation with aniline to break the azeotrope and 5) distillation to separate hydrazine from aniline. Sometimes 50% caustic replaces aniline in the extractive distillation. If ultra pure hydrazine is needed, freeze crystallization is used to remove the supernatant fluid. Assays between 99.5% and 99.99% have been achieved. 

The reaction mixtures are allowed to stand a few hours or overnight and then arc transferred to a 3-1. flask. The water and ammonia are distilled under reduced pressure as rapidly as... 

Dibenzylidene-l,3-ditelluretane1- 3 Under an inert atmosphere, 1.15 g (50 mmol) of sodium are dissolved in 250 ml of liquid ammonia (freshly distilled from sodium). A small amount of iron(III) nitrate is added to the ammonia solution and then 5.1 g (50 mmol) of phenylacetylene are added dropwise to the stirred sodium amide solution over 30 min. The mixture is allowed to stand for 30 min, 6.4 g (50 mmol) of finely powdered tellurium are added, and the ammonia is evaporated from the mixture under protection against atmospheric moisture. Residual liquids are evaporated under vacuum. The residue (sodium phenylethyneteUuiolate) is dissolved in 50 ml of absolute dimethyl sulfoxide and the solution is cooled to 0°. Under continuous cooling, 25 ml of a 2 molar solution of hydrogen chloride in diethyl ether is added slowly. The precipitate is filtered off, washed with water, chloroform, and then recrystallized from dimethylformamide to give the trans-isomer yield 4.3 g (38%) m.p. 270-275°. 

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