288 PRACTICAL ORGANIC CHEMISTRY extracted twice with 20 ml. of 10% sulphuric acid, then with 20 ml. of io% sodium carbonate solution, twice again with the dilute sulphuric acid, and finally twice with 20 ml. of distilled water. The benzene solution is then separated and dried over anhydrous magnesium sulphate or (more slowly) over sodium sulphate. A 75 ml. Claisen flask is fitted with a small dropping-funnel in the main neck, and the filtered benzene solution then run into the flask from the funnel at approximately the rate at which the benzene is being distilled off by heating the flask in an oil-bath. When the solvent has thus been removed, the residue is allowed to cool whilst the funnel is replaced by the usual capillary tube, and the distillation is then continued at low pressure obtained by an efficient water-pump. The ester is obtained as a colourless liquid, b.p. i45-i55°/i5 mm.: yield, 27-30 g. A second dis-tillation gives a product of sharper boiling-point. If during the distillation the ester tends to decompose with foaming, it indi-
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