Concerted effects of substituents in the reaction of [rad]OH with 2-, 3-, and 4-hydroxybiphenyls.

[Display omitted] • Radiolytic yields reflect the charge distribution in the aromatic rings of HBPs. • The OH mostly adds to the ortho and para positions of the phenol in HBPs. • Concerted effects of –OH and –benzyl groups in the reaction of OH with HBPs. • Relative partial yields for the addition of OH to hydroxybiphenyls. Studies on the distribution of products in radiolytic hydroxylation of hydroxybiphenyls (HBPs) to obtain information on the concerted effect of substituent groups at the OH addition site have been conducted. Liquid chromatography was used to analyze the radiolytic products. Results show that OH is selectively added to the free positions of aromatic rings and the directing effect of the substituents was –OH > phenol > phenyl. The yields of each product are provided; these reflect the charge distribution in the HBP, such that the phenyl ring modified the ortho - para directing effect of the –OH substituent. The ratio of addition of the OH to the HBPs obtained provide a quantitative basis for considering the effect of substituents in determining the site of OH attack on these compounds and provides additional valuable data on the attack of the OH for studies on the degradation of aromatic compounds present in polluted waters. [ABSTRACT FROM AUTHOR]