Preparation: Rosenmund, Stephen, ozonolysis
Aldehydes and Ketones · Chemistry
Study notes
Prepare benzaldehyde from toluene without over-oxidation to benzoic acid. Step 1: Strong oxidation (KMnO₄) would give benzoic acid — too far! Step 2: Etard reaction: toluene + CrO₂Cl₂ (chromyl chloride) → chromium complex. Step 3: Hydrolysis → benzaldehyde (stops at aldehyde). Step 4: Controlled oxidation hits the aldehyde stage — Etard's precision!