Phenols - the original antiseptic When hydroxyl groups are attached directly to a benzene ring, they are called phenols. Phenol was first used by the British surgeon Joseph Lister as an antiseptic to reduce post-operative infections in the late 1800 's. While alcohols and phenols share many chemical and physical properties, they also have differences. For this class, the main learning objective is to recognize and distinguish alcohols from phenols. Phenols are easy to recognize by the presence of the benzene ring. A benzene ring is a six carbon ring with alternating double and single bonds as shown below. Benzene The benzene ring of phenols is one of the few rings that can be represented with a condensed formula C_(6)H_(5)OH