14.7: Phenols

ECC: Introduction to General, Organic, & Biochemistry · LibreTexts

0%

Contents

    Text

    Size
    100%
    Theme
    Typeface
    Line length
    Spacing

    From LibreTexts, under CC BY-NC-SA 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Learning Objectives
    • To describe the structure and uses of some phenols

    Compounds in which an OH group is attached directly to an aromatic ring are designated ArOH and called phenols. Phenols differ from alcohols in that they are slightly acidic in water. They react with aqueous sodium hydroxide (NaOH) to form salts.

    \[\ce{ArOH (aq) + NaOH (aq) \rightarrow ArONa (aq) + H_2O} \nonumber \]

    The parent compound, C6H5OH, is itself called phenol. (An old name, emphasizing its slight acidity, was carbolic acid.) Phenol is a white crystalline compound that has a distinctive (“hospital smell”) odor.

    Illustration
    Illustration
    Figure \(\PageIndex{1}\): (Left) Structure of Phenol (right) Approximately two grams of phenol in glass vial. from Wikipedia
    To Your Health: Phenols and Us

    Phenols are widely used as antiseptics (substances that kill microorganisms on living tissue) and as disinfectants (substances intended to kill microorganisms on inanimate objects such as furniture or floors). The first widely used antiseptic was phenol. Joseph Lister used it for antiseptic surgery in 1867. Phenol is toxic to humans, however, and can cause severe burns when applied to the skin. In the bloodstream, it is a systemic poison—that is, one that is carried to and affects all parts of the body. Its severe side effects led to searches for safer antiseptics, a number of which have been found.

    Illustration

    An operation in 1753, painted by Gaspare Traversi, of a surgery before antiseptics were used.

    One safer phenolic antiseptic is 4-hexylresorcinol (4-hexyl-1,3-dihydroxybenzene; resorcinol is the common name for 1,3-dihydroxybenzene, and 4-hexylresorcinol has a hexyl group on the fourth carbon atom of the resorcinol ring). It is much more powerful than phenol as a germicide and has fewer undesirable side effects. Indeed, it is safe enough to be used as the active ingredient in some mouthwashes and throat lozenges.

     

    Illustration
    The compound 4-hexylresorcinol is mild enough to be used as the active ingredient in antiseptic preparations for use on the skin.

    The compound 4-hexylresorcinol is mild enough to be used as the active ingredient in antiseptic preparations for use on the skin.

    Summary

    Phenols are compounds in which an OH group is attached directly to an aromatic ring. Many phenols are used as antiseptics.

    14.7: Phenols is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.