Abstract
Klarmann, Shternov and von Wowern 1 showed that the substitution of one, 2, and 3 atoms of chlorine into the phenol molecule led to a progressive increase in the germicidal action of the resulting compounds. Unfortunately, at the same time the solubility of the phenolic compounds decreased markedly with substitution. The sodium salts of these halogenated phenols possess a considerably greater solubility than the phenols themselves, but there is no explicit information available in the literature as to the actual germicidal power of the phenolates.
Tilley and Schaeffer 2 showed that the germicidal efficiency of phenol decreased with an increase in percentage of sodium hydroxide added until the percentage of sodium hydroxide equalled or slightly exceeded that required to neutralize the phenol. Phenol is a weak acid with the acid dissociation constant K'a = 1.06 × 10-10 at 25°C. 3 Consequently a completely neutralized solution of phenol will be strongly alkaline, and an attempt to evaluate the actual germicidal action of the phenolate is complicated by the alkalinity of the solution. The substitution of chlorine atoms into the phenol molecule increases the strength of the molecule as an acid and makes it possible to evaluate the relative germicidal action of some undissociated phenols and their phenolates without undue interference by excess acidity or alkalinity.
In this investigation 3 substituted phenols: o-chlorophenol, 2, 4 dichlorophenol and 2, 4, 6 trichlorophenol were tested in moderately acid and alkaline solutions. The acid series of solutions were made by diluting weighed quantities of the several phenols with M/60 phosphate buffer of approximately pH 6.1. The alkaline solutions were made by adding standard sodium hydroxide to weighed samples of the phenols to adjust them to the neighborhood of pH 9.8 and diluting with M/60 carbonate buffer at pH 9.8.
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