Phenols are moreacidic than typical alcohols. The acidity of the hydroxyl group in phenols is commonly intermediate between that ofaliphatic alcohols andcarboxylic acids (their pKa is usually between 10 and 12). Deprotonation of a phenol forms a corresponding negativephenolate ion orphenoxide ion, and the correspondingsalts are calledphenolates orphenoxides (aryloxides according to the IUPAC Gold Book).[citation needed]
Many phenols of commercial interest are prepared by elaboration ofphenol orcresols. They are typically produced by the alkylation ofbenzene/toluene withpropylene to formcumene thenO 2 is added withH 2SO 4 to form phenol (Hock process). In addition to the reactions above, many other more specialized reactions produce phenols:
The best-selling drug in the U.S.,Acetaminophen, also known as Paracetamol, is a phenol.
There are variousclassification schemes.[15]: 2 A commonly used scheme is based on the number of carbons and was devised byJeffrey Harborne and Simmonds in 1964 and published in 1980:[15]: 2 [16]
More than 371 drugs approved by the FDA between the years of 1951 and 2020 contain either a phenol or a phenolic ether (a phenol with an alkyl), with nearly every class of small molecule drugs being represented, and natural products making up a large portion of this list.[17]
^H. E. Ungnade, E. F. Orwoll (1943). "3-Bromo-4-hydroxytoluene".Organic Syntheses.23: 11.doi:10.15227/orgsyn.023.0011.
^Bracegirdle, Sonia; Anderson, Edward A. (2010). "Arylsilane oxidation—new routes to hydroxylated aromatics".Chem. Comm.46 (20):3454–6.doi:10.1039/b924135c.PMID20582346.S2CID31736757.
^Harborne, J. B. (1980). "Plant phenolics". In Bell, E. A.; Charlwood, B. V. (eds.).Encyclopedia of Plant Physiology, volume 8 Secondary Plant Products. Berlin Heidelberg New York: Springer-Verlag. pp. 329–395.