Steam distillation of phenolic compounds in the presence of a large amount of sodium chloride

Abstract

The steam distillation of phenolic compounds in the presence of a large amount of sodium chloride was studied by use of a semimicro steam distillation apparatus and ultraviolet spectrometry. The recovery of many phenolic compounds in steam distillation was improved by the addition of the sodium chloride, particularly in the case of 3- and 4-methoxyphenol, 3-and 4-bromophenol, and 3- and 4-chlorophenol (essentially complete recovery was obtained with the latter four compounds). The recovery with 2-chlorophenol was about 5% lower. The recovery with 2-nitrophenol was about 10% lower and the results tended to be erratic (probably because the sodium chloride affects the intramolecular hydrogen bonding of this polar compound). The addition of sodium chloride did not improve the very low recoveries obtained with aminophenols and di- and trihydroxyphenols without sodium chloride. It is recommended that sodium chloride be used in the determination of total phenolic compounds in waters in procedures that require a steam distillation, since more complete recovery is obtained for the phenolic compounds that are likely to be found in waters.