Liquid‐phase oxidation of p‐cresol and Substituted p‐Cresols by Air

The liquid‐phase oxidation of p‐cresol and substituted p‐cresols by air under alkaline conditions using cobaltous chloride as a catalyst and methanol as solvent, has been investigated with a view to obtain the corresponding aldehydes with sufficiently high selectivities. In the case of p‐cresol, the effects of various process parameters on the reaction rate and selectivity with respect to the aldehyde have been investigated. The results obtained are likely to be useful for the development of processes for the production of industrially relevant products such as 4‐hydroxybenzaldehyde, vanillin and syringaldehyde by using p‐cresol as the starting material. Various alternative process schemes have been proposed and evaluated.