Etard reaction is a specific method to convert methylbenzene to benzaldehyde using CrO\textsubscript{2}Cl\textsubscript{2}. It avoids over-oxidation to carboxylic acids.
Etard reaction involves the oxidation of toluene (or methyl-substituted aromatic compounds) to benzaldehyde using chromyl chloride (CrO2Cl2) in carbon disulfide (CS2) followed by hydrolysis. This method selectively oxidizes the methyl group to the aldehyde without affecting the aromatic ring.