Drying of ether

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

The drying of ethereal solutions is an operation frequently met with. In most cases it is advisable to dry an ethereal extract before evaporating off the ether. Again, to dry a moist solid, it is often convenient to dissolve it in ether and to dry the ethereal solution with a dehydrating agent. The dry solid is then obtained by evaporation. For the drying of organic liquids by dialysis, see U. S. P., 1,885,393. 

For general use in the drying of ethereal extracts, one of us previously recommended shaking with saturated sodium chloride solution and filtering through a cone of anhydrous sodium sulfate which see), but he is now convinced by the literature cited and from personal trials that calcium sulfate is definitely superior. In one informative experiment, ether was saturated with water at 25° and a ItlO-ml. 

The ethereal extracts are then united, dried with a suitable drying agent and filtered. The filtrate is then cautiously distilled, the ether being first distilled and finally the organic compound if volatile if the compound is solid, the crude residue is purified by recrystallisation. Very great care must be taken on all occasions when ether is distilled because of the risk of fire or of an explosion full experimental details for this operation are given, both on p. 8o (Preparation of Ether) and on p. 164 (Pre-... 

Filter off the glycine through a Buchner funnel, and then transfer it to a beaker, add 80 ml. of methanol and stir the mixture well. Then filter again, wash the glycine on the filter with a small quantity of ether, drain and dry. 

In view of the small volume of nitromethane to be manipulated, the crude nitromethane may be extracted from the aqueous distillate with ether (30-40 ml.). Dry the ethereal extract over sodium sulphate, filter through a fluted filter-paper, and then distil off the ether on a water-bath with the usual precautions (Fig. 64, p. 163 Fig, 23(E), p. 45) finally distil the residual nitromethane. 

Place the distillate in a separating-funnel and extract the benzonitrile twice, using about 30 ml. of ether for each extraction. Return the united ethereal extracts to the funnel and shake with 10% sodium hydroxide solution to eliminate traces of phenol formed by decomposition of the benzenediazonium chloride. Then run off the lower aqueous layer, and shake the ethereal solution with about an equal volume of dilute sulphuric acid to remove traces of foul-smelling phenyl isocyanide (CaHjNC) which are always present. Finally separate the sulphuric acid as completely as possible, and shake the ether with water to ensure absence of acid. Run off the water and dry the benzonitrile solution over granular calcium chloride for about 20 minutes. 

Now transfer the cold distillate to a separating-funnel, and shake vigorously with about 50-60 ml. of ether run oflF the lower aqueous layer and then decantf the ethereal solution through the mouth of the funnel into a 200 ml. conical flask. Replace the aqueous layer in the funnel, and extract similarly twice more with ether, combining the ethereal extracts in the conical flask. Add 3-4 g. of dry powdered potassium carbonate to the ethereal solution, securely cork the flask and shake the contents gently. The ethereal solution of the phenol... 

Extract the dimethylaniline by shaking the distillate in a separating-funnel with a few ml. of ether, and then dry the ethereal solution over potassium carbonate distil the filtered ethereal solution from a small distilling-flask e.g, Fig. 36, p. 63) with the usual precautions, and finally the dimethylaniline, b.p. 193°. Yield, almost theoretical. 

Cool the mixture and pour the liquid reaction product into a separating-funnel. Rinse out the flask (which may contain some unchanged zinc) with ether, pour the latter into the funnel, and extract the aqueous solution with the ether. Repeat the extrac tion with a second quantity of ether, unite the ether extracts, wash them by extracting once with water, and then dry the ethereal extract over sodium sulphate. 

Filter the dried extract, and then distil off the ether from a small flask, using the customary precautions if the volume of ether is large, fit a dropping-funnel to the flask so that the ethereal extract can be run into the flask as the ether distils off cf. Fig. 23(E), p. 45). When the ether has been removed, replace the water-condenser by an air-condenser, and continue... 

When the reaction has subsided, boil the reaction-mixture under reflux for 2 hours then make it alkaline with sodium hydroxide solution, and distil it in steam until oily drops no longer come over in the aqueous distillate (1 2 litres). Extract the distillate thoroughly with ether ca. 150 ml.), and dry the ethereal extract over powdered sodium hydroxide. Filter the dry extract through a fluted filter-paper moistened with ether into a 200 ml. flask. Fit the flask with a distillation-head, or a knee-tube , and distil off the ether. Now replace the distillation-head by a reflux water-condenser, add 10 ml. of acetic anhydride, and boil the mixture under reflux for 10 15 minutes. 

If no solid precipitate is obtained but the solution becomes cloudy, a low-melting or liquid phenol is indicated this will, of course, be revealed also by the characteristic phenolic odour. Transfer to a separating-funnel and extract with an equal volume of ether. Separate and dry with anhydrous sodium sulphate. Distil off the ether and identify the residue. 

In practice, it is best to purify a quantity, say one Winchester quart bottle, of technical 0 720 ether to cover the requirements of a group of students. The Winchester quart of ether is divided into two approximately equal volumes, and each is shaken vigorously in a large separatory funnel with 10-20 ml. of the above ferrous solution diluted with 100 ml. of water. The latter is removed, the ether transferred to the Winchester bottle, and 150-200 g. of anhydrous calcium chloride is added. The mixture is allowed to stand for at least 24 hours with occasional shaking. Both the water and the alcohol present are thus largely removed. The ether is then filtered through a large fluted filter paper into another clean dry Winchester bottle (CAUTION all flames in the vicinity must be... 

Use the apparatus detailed in Section 111,20. Dissolve 100 g. (123 ml.) of methyl n-butyl ketone (2-hexanone) (Section 111,152) in 750 ml. of ether and add 150 ml. of water. Introduce 69 g. of clean sodium in the form of wire (or small pieces) as rapidly as possible the reaction must be kept under control and, if necessary, the flask must be cooled in ice or in running water. When all the sodium has reacted, separate the ethereal layer, wash it with 25 ml. of dilute hydrochloric acid (1 1), then with water, dry with anhydrous potassium carbonate or with anhydrous calcium sulphate, and distil through a fractionating column. Collect the fraction of b.p. 136-138°. The yield of methyl n-butyl carbinol (2-hexanol) is 97 g. 

Now run in a solution of 52 g. (53-5 ml.) of pure diethyl carbonate (1) in 70 ml. of anhydrous ether, with rapid stirring, over a period of about one hour. A vigorous reaction sets in and the ether refluxes continually. When the diethyl carbonate has been added, heat the flask on a water bath with stirring for another hour. Pour the reaction mixture, with frequent shaking, into a 2 litre round-bottomed flask containing 500 g. of crushed ice and a solution of 100 g. of ammonium chloride in 200 ml. of water. Transfer to a separatory funnel, remove the ether layer, and extract the aqueous solution with two 176 ml. portions of ether. Dry... 

Dibromobutane (from 1 4-butanediol). Use 45 g. of redistilled 1 4-butanediol, 6-84 g. of purified red phosphorus and 80 g. (26 ml.) of bromine. Heat the glycol - phosphorus mixture to 100-150° and add the bromine slowly use the apparatus of Fig. Ill, 37, 1. Continue heating at 100-150° for 1 hour after all the bromine has been introduced. Allow to cool, dilute with water, add 100 ml. of ether, and remove the excess of red phosphorus by filtration. Separate the ethereal solution of the dibromide, wash it successively with 10 per cent, sodium thiosulphate solution and water, then dry over anhydrous potassium carbonate. Remove the ether on a water bath and distil the residue under diminished pressure. Collect the 1 4-dibromobutane at 83-84°/12 mm. the yield 3 73 g. 

In a 500 ml. three-necked flask, equipped with a thermometer, a sealed Hershberg stirrer and a reflux condenser, place 32-5 g. of phosphoric oxide and add 115-5 g. (67-5 ml.) of 85 per cent, orthophosphoric acid (1). When the stirred mixture has cooled to room temperature, introduce 166 g. of potassium iodide and 22-5 g. of redistilled 1 4-butanediol (b.p. 228-230° or 133-135°/18 mm.). Heat the mixture with stirring at 100-120° for 4 hours. Cool the stirred mixture to room temperature and add 75 ml. of water and 125 ml. of ether. Separate the ethereal layer, decolourise it by shaking with 25 ml. of 10 per cent, sodium thiosulphate solution, wash with 100 ml. of cold, saturated sodium chloride solution, and dry with anhydrous magnesium sulphate. Remove the ether by flash distillation (Section 11,13 compare Fig. II, 13, 4) on a steam bath and distil the residue from a Claisen flask with fractionating side arm under diminished pressure. Collect the 1 4-diiodobutane at 110°/6 mm. the yield is 65 g. 

In a 1-litre three-necked flask, mounted on a steam bath and provided respectively with a separatory funnel, mechanical stirrer and double surface condenser, place 165 g. of bromoform (96 per cent.). Add 10 ml. of a solution of sodium arsenite made by dissolving 77 g. of A.R. arsenious oxide and 148 g. of A.R. sodium hydroxide in 475 ml. of water. Warm the mixture gently to start the reaction, and introduce the remainder of the sodium arsenite solution during 30-45 minutes at such a rate that the mixture refluxes gently. Subsequently heat the flask on the steam bath for 3-4 hours. Steam distil the reaction mixture (Fig. 11, 41, 1) and separate the lower layer of methylene bromide (79 g.). Extract the aqueous layer with about 100 ml. of ether a further 3 g. of methylene bromide is obtained. Dry with 3-4 g. of anhydrous calcium chloride, and distil from a Claisen flask with fractionating side arm. The methylene bromide boils constantly at 96-97° and is almost colourless. 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

Into a 500 ml. three-necked flask, provided with a mechanical stirrer, a gas inlet tube and a reflux condenser, place 57 g. of anhydrous stannous chloride (Section 11,50,11) and 200 ml. of anhydrous ether. Pass in dry hydrogen chloride gas (Section 11,48,1) until the mixture is saturated and separates into two layers the lower viscous layer consists of stannous chloride dissolved in ethereal hydrogen chloride. Set the stirrer in motion and add 19 5 g. of n-amyl cyanide (Sections III,112 and III,113) through the separatory funnel. Separation of the crystalline aldimine hydrochloride commences after a few minutes continue the stirring for 15 minutes. Filter oflF the crystalline solid, suspend it in about 50 ml. of water and heat under reflux until it is completely hydrolysed. Allow to cool and extract with ether dry the ethereal extract with anhydrous magnesium or calcium sulphate and remove the ether slowly (Fig. II, 13, 4, but with the distilling flask replaced by a Claisen flask with fractionating side arm). Finally, distil the residue and collect the n-hexaldehyde at 127-129°. The yield is 19 g. 

Pour the reaction mixture into a 1-litre round-bottomed flaak, add 250 ml. of water, fit a still head and a condenser for downward distillation (Fig. II, 13, 3, but without the thermometer). Distil the mixture until about 125 ml. of distillate (two layers) have been collected. Saturate with salt (about 30 g. are required), and separate the upper layer of cj/cZohexanone extract the aqueous layer with 25-30 ml. of ether and combine the ether extract with the cycZohexanone layer. Dry with about 6 g. of anhydrous sodium or magnesium sulphate, filter the solution into a distilling flask of suitable size to which a condenser has previously been attached. Distil oflF the ether from a water bath—a beaker containing warm water is satisfactory. Distil the residual liquid from an air bath or a wire gauze, and collect the cyclohexanone at 153-156°. The yield is 16 g. 

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