The Reaction of Chlorine Dioxide with Phenol in an Aqueous Solution

Abstract

The reaction of chlorine dioxide (ClO^2-) with phenol in an aqueous solution was studied and the products formed by this reaction, mainly chlorophenols, were separated and determined by 'gas chromatography.
In an acidic solution, o- and p-chlorophenol formed in this reaction, but further chlorinated phenols were not detected. The concentrations of these monochlorophenols became maximum when the initial molar ratio ([Cl00] [Phenol]) was O.6 and they were not detected when the initial molar ratio was above 1.2. The maximum yields of o- and p-chlorophenol were ca.2% and 8%, respectively (Fig.2). These results quite differ from that of the reaction between chlorine and phenol (Fig.11). Other product also formed in a small amount. The formation of dichlorocyclohexenone was suggested by GC-MS method (Fig.3)
. In a basic solution, the amount of chlorine dioxide necessary to extinguish a phenol became larger than that in an acidic solution and a small amount of 2, 4- and 2, 6-dichlorophenol together with monochlorophenols formed. The maximum yields of 2, 4- and 2, 6-dichlorophenol were ca. O.3% and 0.1%, respectively (Fig.4).
It was concluded from the above results, that when a chlorine dioxide is used in the treatment of water containing phenol, taste and odor of chlorophenols are scarcely perceived.