Sodium chloride precipitation

Lithium chlorate [13453-71 -9] LiClO, has rhombic needles mp 124—129°C decomposes on heating to 270°C. It is one of the most soluble salts known and it is very hygroscopic. LiClO is prepared by adding lithium chloride [7447-41-8] to sodium chlorate solution. Sodium chloride precipitates, the hquor is concentrated, and the lithium chlorate is filtered and dried. It has limited use in pyrotechnics. 

A large quantity of sodium chloride precipitates during addition of the epichlorohydrin. 

Once the two salts are mixed in solution (acetone is a common solvent for this), the sodium chloride precipitates and is removed by filtration. The solvent is then removed under reduced pressure and, since salts have no vapour pressure, the ionic liquid remains in the flask. The problem with this reaction is that it is almost impossible to remove the last traces of chloride ions. The chloride not only influences the physical properties of the liquid such as melting point and viscosity, but is also a good nucleophile and can deactivate catalysts and affect reproducibility. A great deal of effort has been directed towards removal of the chloride contamination, including washes and chromatography, but none have proved to be completely effective [9], This has led to the development of some alternative synthetic routes. Simply exchanging Na[BF4]... 

To obtain MSMA, the DSMA solution is partially acidified with sulfuric acid and the resulting solution concentrated by evaporation. As the aqueous solution is being concentrated, a mixture of sodium sulfate and sodium chloride precipitates out (about 0.5 kg per 100 kg of active ingredient). These salts are a troublesome disposal problem because they are contaminated with arsenic. The salts are removed by centrifugation, washed in a multistage, countercurrent washing cycle, and then disposed of in an approved landfill. 

Reaction with allyl urea and methanol, followed by dilution with water and treatment with sodium chloride, precipitates methoxy(urea)propyhnercuric chloride, also known as chloromerodrin, a diuretic agent. 

Kuryla and Leis [125a] recently reported that ortho esters are readily produced by the slow addition of vinylidene chloride to a sodium j8-alkoxy-alcoholate, dissolved or suspended in a solvent. The reaction is exothermic and produces either the ketene acetal or the ortho ester derivative while sodium chloride precipitates (Eq. 38). 

In a hood, 4.1 moles of the sodium salt of a carboxylic acid is dissolved in just enough of the anhydrous free acid to make a mobile solution. Then 1 mole of the ketazine is added and, with stirring at 10°-20°C, one equivalent of chlorine is slowly passed through the solution. Sodium chloride precipitates rapidly during this addition. Stirring is continued for hr at 20°C after the addition has been completed. Then the reaction mixture is poured into 5-8 volumes of an ice-water mixture and the product is extracted with ether. The product is separated from the solvent either by distillation or by crystallization. 

Chloride is removed from the ether solution of aluminum trihydride by the addition of sodium tetrahydroborate. The LiBH4 remains in solution, while the sodium chloride precipitates and is removed by filtration. Best results are obtained when NaBH4t is dried under vacuum at 60°C. for 8 hours and ground to 1 /urn. or smaller. This last step is particularly important since both the reaction rate and efficiency of chloride removal are a function of NaBH4 particle size. 

Ohtsuka, T. 8t Matsuda, M. In Situ Raman Spectroscopy for Corrosion Products of Zinc in Humidified Atmosphere in the Presence of Sodium Chloride Precipitate Corrosion 2003, 59, 407—113. 

After the flask containing the sodium borohydride solution has cooled for about half an hour, the tributyltin chloride solution is added dropwise with rapid stirring over a 30-minute period. A white sodium chloride precipitate forms as each drop of the tributyltin chloride solution is added. The reaction mixture is allowed to stand at —10 to — 11°C. for 10-15 minutes after the last of the tributyltin chloride solution has been added. Without filtration, the entire reaction mixture is now transferred cold under nitrogen or helium into a 1-1., single-necked, round-bottomed flask the flask is attached to a flash evaporator (Buchler Model PTFE-1G or equivalent) and immersed in a bath maintained at 0°C. The evaporator s receiving flask (also 1-1., single-necked, round-bottomed) is immersed in a — 80°C. bath of Dry Ice-acetone. 

The nitrogen flow is stopped and the inlet and outlet of the flask are stoppered. The benzene solution is then stirred for 5 min by means of a magnetic stirring bar. The methanolic hydrochloric acid solution is then added dropwise to the stirred benzene solution over a period of 15-20 min during this time the solution becomes deep-red in color and sodium chloride precipitates. Stirring is continued for 2 hr. The following operations are performed in the open air. The volume of the reaction mixture is reduced to a minimum with the aid of a Roto-evaporator, and 80 mL of water and 100 mL of n-hexane are added successively to the residue. The aqueous layer is quickly discarded and the organic layer dried over 5 g of anhydrous sodium sulfate for a few minutes. The sodium sulfate is removed by filtration, and the volume of the filtrate is reduced with the aid of a roto-evaporator to leave a dark-red, oily residue. 

Taylor was unable to separate catheptic from peptic activity, either by ammonium sulfate and sodium chloride precipitation, or by ion-exchange chromatography, free boundary electrophoresis (Fig. 2), or differential ultracentrifugation (T24, T26). 

Two grams of 4-bromo-l-phenyl-2 3-dimethyl-5-pyrazolon.e (1 mol.) and 10 5 grams of mercuric acetate (4 mols., 90 percent.) are heated for tliirty minutes in an oil-bath at 160° C. The melt is cooled, extracted with alcohol, the solution boiled with charcoal, filtered, and treated with ether. The white precipitate is filtered, washed with ether, and dried. It is a hygroscopic substance, readily soluble in cold water, less soluble in methyl or ethyl alcohol faintly acidified with acetic acid. It decomposes with gas evolution at 225° C., and is unaffected by ammonium sulphide unless boiled. From its aqueous solution sodium chloride precipitates an insoluble chloride and sodium hydroxide the corres X)nding hydroxide. 

Mannitol solutions, 20% w/v or stronger, may be salted out by potassium chloride or sodium chloride. Precipitation has been reported to occur when a 25% w/v mannitol solution was allowed to contact plastic. Sodium cephapirin at 2 mg/mL... 

An alkyl iodide is often prepared from the corresponding bromide or chloride by treatment with a solution of sodium iodide in acetone the less soluble bromide or sodium chloride precipitates from solution and can be removed by filtration. 

Bismuth chloride (6.3 g, 20 mmol) was dissolved in absolute ethanol, and sodium ethoxide (4.08 g, 60 mmol) was added dropwise in the same solvent. After exothermic reaction, sodium chloride precipitated as a fine white solid. This was filtered off and the filtrate was concentrated in vacuo at room temperature to give Bi(OEt)3 as colorless crystals with a fiuit-like odor. The compound is very sensitive to moisture and decomposes slowly on prolonged storage. It is poorly soluble in organic solvents. Yield, 6.0 g (86%) [76ZAAC(423)47]. 

If concentrated hydrochloric acid is placed in a clear saturated sodium chloride solution, then white sodium chloride precipitates as fine crystals (see E6.4). They trickle into the glass from above to below and fall to the bottom. The drastic increase in concentration of Cl (aq) ions causes a disturbance in equilibrium, and so much sodium chloride precipitates until a new equilibrium with higher concentrations of Cl (aq) ions than of Na+ ions sets in (see Fig. 6.5). The new saturated... 

Practically insol in methanol, ethanol, ether, acelone. Does not dialyze through a cellophane membrane at room temp but passes through a Seitz filter. Sodium chloride precipitates the active principle in acerin preparations as does also normal serum with 1 800 solns of acerin. Strong acerin preparations acquire reddish-brown color after treatment with alkali and oxidation in air. In general, the substance behaves similarly to vegetable tannins. It is practically nonloxic to rabbits and mice when administered s.c. 

Pure sodium chloride precipitates from the solution, the impuri-... 

Why does sodium chloride precipitate, whereas the impurities do not ... 

B. Courtois, an entrepreneur from the French town of Dijon, was engaged, among other things, in the production of potash and saltpeter. He used ash of sea algae as the initial raw material. A mother solution of sea algae was formed under the action of water on the ash. To-day we know that the ash contains chlorides, bromides, iodides, carbonates, and sulphates of some alkali and alkaline-earth metals. However, when Courtois performed his experiments it was only known that the ash contained potassium and sodium compounds (chlorides, carbonates, and sulphates). Upon evaporation, first, sodium chloride precipitated and then potassium chloride and sulphate. The residual mother solution contained a complex mixture of various salts, including sulphur-containing ones. 

With concentrated calcium chloride solutions, sodium chloride precipitates after part of the sodium hypochlorite is added. After filtration, the remainder of the sodium hypochlorite is added. Calcium hypochlorite dihydrate then crystallizes. It is separated from the solution and dried. Chlorinating a slurry of lime in a sodium hypochlorite solution prevents the formation of calcium chloride and allows large crystals of calcium hypochlorite dihydrate to form. These are readily separated and dried. ... 

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