When treated with a metal catalyst such as palladium (Pd) or platinum (Pt) and hydrogen gas (H2) ketones next to aromatic groups are converted to alkanes.
This is the redox reaction in which the acyl group can be completely reduced to alkyl group by using palladium-catalyzed hydrogenation. Conversely, the methylene group next to the aromatic ring in an alkylarene is susceptible to oxidation to the carbonyl function with the use of chromium trioxide (CrO3) and sulfuric acid (H2SO4).
Acyl is the meta director, and alkyl is ortho, para director. Thus, this reaction allows the introduction of substituents in each position (ortho, meta, para) of a molecule in both compounds (acyl and alkyl).