Steam/water distillation fractionation

Ethyl isobutyrylisobutyrate. Add 24-6 g. (28-3 ml.) of ethyl iso-butyrate, b.p. 110-111°, to the solution of ca. 0 21 mol of sodium triphenyl-methide in approximately 1400 ml. of ether contained in the 2-litre conical flask. Stopper the flask, shake well to effect complete mixing, and keep at room temperature for 60 hours. Acidify the reaction mixture by adding, with shaking, 15 ml. of glacial acetic acid, and then extract with 100 ml. of water. Wash the ethereal solution with 50 ml. portions of 10 per cent, sodium carbonate solution until free from excess acid, dry over anhydrous magnesium sulphate, and distil off the ether on a steam bath. Distil the residue under reduced pressure from a Claisen flask with fractionating side arm (Figs. II, 24, 4—5). Collect the ethyl isobutyryl isobutyrate at 95-96°/18 mm. the yield is 15 g. The b.p. at atmospheric pressure is 201-202°. 

The details of this preparation are practically the same as those given for p-tolu-nitrile (Preparation 82). A cuprous-potassium cyanide solution, prepared as therein described, is warmed to about 70°, and added in small portions to a solution of benzene-diazonium chloride prepared from 18-6 gms. (1 mol.) of aniline as described in Preparation 379. When the addition is complete, the liquid is warmed on a water bath for 15 minutes and distilled in steam the distillate is extracted with ether. The ethereal solution is washed repeatedly with dilute caustic soda and with dilute sulphuric acid, dried over anhydrous potassium carbonate, filtered, and the oil which remains on driving off the ether fractionated. Owing to the evolution of cyanogen and hydrocyanic acid, this preparation must be carried out in a good fume cupboard. 

Benzyl chloride (2 molecular equivalents), phosphonium iodide (2 equivalents) and zinc oxide (1 equivalent) are heated together at 160° C., and the reaction mixture then distilled in steam, an oil heavier than water distilling over. After drying the crude product over potassium hydroxide, the oil is fractionated in hydrogen, the phosphine distilling at 180° to 190° C., further distillation giving a product of B.pt. 180° C. The residue left after the distillation contains dibenzylphospliine. 

Solvents with boiling points below 90-95°. A steam bath or water bath should be employed. Alternatively, the apparatus of Fig. 77,13, 3, but with a Alter flask as receiver, may be used the end of the rubber tubing attached to the tubulure is either placed in the sink or allowed to hang over the bench. If a distillation is ultimately to be conducted in the flask from which the solvent is removed, the apparatus depicted in Fig. 77,13, 4 is recommended the distilling flask may be replaced by a Claisen flask or a Claisen flask with fractionating side arm, particularly if the subsequent distillation is to be conducted under diminished pressure. 

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