Ketones of Four or Five Carbons

Abstract

Several billion pounds of ketones are produced annually for industrial use in the United States and worldwide. Those with the highest production volumes include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4‐hydroxy‐4‐methyl‐2‐pentanone, isophorone, mesityl oxide, and acetophenone. Common methods used to manufacture ketones include aliphatic hydrocarbon oxidation, alcohol dehydration with subsequent oxidation, dehydrogenation of phenol, alkyl aromatic hydrocarbon oxidation, and condensation reactions. Ketones are commonly used in industry as solvents, extractants, chemical intermediates, and, to a lesser extent, flavor and fragrance ingredients. Although a common effect of excessive ketone exposure is CNS depression some ketones have pulmonary effects that are well below levels that cause acute CNS effects. For example, ketones such as diacetyl and chemically similar chemicals used for flavoring foods, coffee, and e‐cigarettes provide opportunities for widespread exposure and very debilitating pulmonary disease including bronchiolitis obliterans.