Valerophenone, or butyl phenyl ketone, is an aromatic ketone with the formula C<sub>6</sub>H<sub>5</sub>C(O)C<sub>4</sub>H<sub>9</sub>. It is a colorless liquid that is soluble in organic solvents. It is usually prepared by the acylation of benzene using valeryl chloride.
Being prochiral, valerophenone undergoes enantioselective hydrogenation to the corresponding alcohol.
Its photochemistry has been studied.
Valerophenone is also an inhibitor of the enzyme carbonyl reductase.