Steam/water distillation ester hydrolysis

The phenol (Imol) in 5% aqueous NaOH is treated (while cooling) with benzoyl chloride (Imol) and the mixture is stirred in an ice bath until separation of the solid benzoyl derivative is complete. The derivative is filtered off, washed with alkali, then water, and dried (in a vacuum desiccator over NaOH). It is recrystalUsed from ethanol or dilute aqueous ethanol. The benzoylation can also be carried out in dry pyridine at low temperature ca 0°) instead of in NaOH solution, finally pouring the mixture into water and collecting the solid as above. The ester is hydrolysed by refluxing in an alcohol (for example, ethanol, n-butanol) containing two or three equivalents of the alkoxide of the corresponding alcohol (for example sodium ethoxide or sodium n-butoxide) and a few ca 5-10) millilitres of water, for half an hour to three hours. When hydrolysis is complete, an aliquot will remain clear on dilution with four to five times its volume of water. Most of the solvent is distilled off. The residue is diluted with cold water and acidified, and the phenol is steam distilled. The latter is collected from the distillate, dried and either fractionally distilled or recrystalUsed. 

Whereas diethyl phosphorofluoridate was hydrolysed in aqueous solution in about 4 hr., the di-isopropyl ester required 72 hr. for complete hydrolysis, and small quantities could be steam-distilled. DicycZohexyl phosphorofluoridate was very stable, and vigorous shaking with water did not produce any appreciable hydrolysis. It was hydrolysed by boiling water only after several hours. When stirred vigorously with 2 per cent sodium hydroxide solution at 28-5°, the time taken to bring about hydrolysis according to the equation... 

In the second step, a distillation-reaction system is appHed to prevent hydrolysis of epichlorohydrin, by removing epichlorohydrin and water as an azeotropic mixture from the top of the distillation column. This operation is known as steam-stripping. In addition to being used in the synthesis of epichlorohydrin, AC is also used as a raw material for synthesizing other aHyl compounds such as aHyl esters, aHyl ethers, and aUylamines by nucleophilic substitution, utilizing the easily substituting property of its chloride group. 

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