Salt columns

Poole SK, Furton KG, Poole CF. 1988. Determination of benzene and toluene in gasoline by gas chromatography using a liquid organic salt column. J Chromatogr Sci 26 67-73. 

Examples of cylindrical symmetry related to the preferential importance of the vertical direction are the salt columns in the Dead Sea (Figure 2-9a) as well as the stalactites and the stalagmites in caves (Figure 2-9b), both formed of calcium carbonate. 

Figure 2-9. (a) Salt columns in the Dead Sea. Drawing by Ferenc Lantos after a color slide of... 

Conversion of the salt of a weak base into the free base. Prepare a column of a strong base anion resin (such as Amberlite IRA-40o(OH) ) washed with distilled water as above. Drain off most of the water and then allow 100 ml. of A//2.Na.2C03 solution to pass through the column at 5 ml. per minute. Again wash the column with 200 ml. of distilled water. Dissolve 0-05 g. of aniline hydrochloride in 100 ml. of distilled water and pass the solution down the column. The effluent contains aniline in solution and free from all other ions. 

Di-n-butyl ether. Technical n-butyl ether does not usually contain appreciable quantities of peroxides, unless it has been stored for a prolonged period. It should, however, be tested for peroxides, and, if the test is positive, the ether should be shaken with an acidified solution of a ferrous salt or with a solution of sodium sulphite (see under Diethyl ether). The ether is dried with anhydrous calcium chloride, and distilled through a fractionating column the portion, b.p. 140-141°, is collected. If a fraction of low boiling point is obtained, the presence of n-butyl... 

Ethyl formate. Reflux a mixture of 61 g. (50 ml.) of A.R. formic acid (98/100 per cent.) and 31 g. (39-5 ml.) of absolute ethyl alcohol for 24 hours. Transfer to a Claisen flask with fractionating side arm (or attach a fractionating column to the flask), distil and collect the liquid passing over below 62°. Wash the distillate with saturated sodium bicarbonate solution and saturate with salt before removing the ester layer. Dry with anhydrous sodium or magnesium sulphate, filter, and distil. The ethyl formate passes over at 53-54°. The yield is 36 g. 

Treat the combined distiUates of b.p. 195-260° with anhydrous potassium carbonate to neutralise the Uttle formic acid present and to salt out the allyl alcohol. Distil the latter through a fractionating column and collect the fraction of b.p, up to 99° separately this weighs 210 g, and consists of 70 per cent, allyl alcohol. To obtain anli5 dious allyl alcohol, use either of the following procedures —... 

Cool the mixture and decant the solution from the sodium bromide wash the salt with two 20 ml. portions of absolute alcohol and add the washings to the main solution. Distil off the alcohol, which contains the slight excess of n-propyl bromide used in the condensation, through a short fractionating column from a water bath. The residue A) of crude ethyl n-propylacetoacetate may be used directly in the preparation of methyl n-butyl ketone. If the fairly pure ester is required, distil the crude product under diminished pressure and collect the fraction boihng at 109-113727 mm. (183 g.) (R). 

Olah and his co-workers compared the behaviour of nitronium salts in competitive nitrations with the behaviour of other nitrating systems. The results are given in table 4.1, columns (a)-(j), and also in table 4.2. The results obtained from competitive nitrations using solutions of nitric acid in organic solvents (table 4.1, columns (6)-(e)) are in line with those obtained by earlier workers. The evidence that in nitromethane,... 

With the more concentrated solution the results, as regards loss of intermolecular selectivity, were similar to those obtained with nitronium salts (table 4.1, column a), whilst with the more dilute solution a more usual situation was revealed. The significance of the former observations is again open to doubt because of the likelihood that mixing was relatively slow, and also because reaction upon encounter is here a serious probability. 

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