PREPARATIONS 245 of hydrolysis are acidic in type: if the hydrolysis is carried out with sodium C 6 H 1 COOC 6 H 6 + H 8 O = C 6 H 6 COOH -f C 8 H 5 OH hydroxide, both compounds remain in solution as their sodium derivatives. They may, however, be separated by acidifying the solution (in order to liberate both acid and phenol) and then adding an excess of sodium carbonate. The benzoic acid readily displaces carbonic acid giving sodium benzoate, whereas the phenol is too weakly acidic to give a similar reaction and so remains free in solution (cf. p. 347). Boil a mixture of i g. of phenyl benzoate and 15 ml. of 10% aqueous sodium hydroxide* in a 50 ml. conical flask under reflux until the molten ester has completely disappeared (about i hour). During the boiling, a small quantity of unchanged ester may have volatil-ised in the steam and crystallised again in the condenser: therefore pour about 3 ml. of 10% sodium hydroxide solution down the condenser to dislodge this ester, and continue the boiling for a further 10 minutes
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