Overview Alcohols are one of the most important functional groups in organic chemistry. The name of alcohol comes from the hydrocarbon from which it is derived. Alcohols are organic molecules containing the functional hydroxyl or -OH group directly bonded to carbon. Phenols have an OH group directly attached to a benzene ring. While alcohols are colorless, phenol is a white crystalline compound with a characteristic "hospital smell" odor. As with other organic compounds, alcohols and phenols are named by formal and standard systems. The most adopted system is the International Union of Pure and Applied Chemistry (IUPAC). The IUPAC names of the alcohols are derived by adding the suffix 'ol' to the name of the parent alkane. Phenols, on the other hand, are named as hydroxy derivatives of benzene. 'Phenol' is used as the parent name rather than benzene. Like all organic compounds, alcohols and phenols have several commercial applications. For instance, ethanol is the main ingredient in alcoholic beverages like wine or beer. Phenols are widely used as antiseptics and as disinfectants. Naming Alcohols The table below shows the classification and nomenclature of some alcohols and phenols. Skeletal Structures IUPAC Name Common Name 1-butanol n-butyl alcohol 2-butanol sec-butyl alcohol 2-methyl-2-butanol t-amyl alcohol 2-bromo-4-chlorocyclopentanol - 2-propen-1-ol allyl alcohol 3-cyclohexen-1-ol - 1,2-ethanediol ethylene glycol 1,2,3-propanetriol glycerol phenol phenol benzene-1,3-diol resorcinol 2-methylphenol o-cresol 3-methylphenol m-cresol 4-methylphenol p-cresol