Based on the findings of Kennedy and Stock in J. Org. Chem. 25, 11, 1901-1906, it's likely that at least one of the methyl groups has been converted
to an acid - when Oxone was reacted with toluene, the result was benzoic acid, in a yield of around 50%. However, the reaction time was much longer:
22 hours under reflux.
Where it gets a little more complicated is that when Oxone was a reacted with salicaldehyde (2-hydroxybenzaldehyde), the result was catechol - the
molecule lost the aldehyde group and -OH was added directly to the ring. Similarly, when reacted with phenol, the result was hydroquinone
(1,4-dihydroxybenzene). Both of these reactions were conducted at room temperature or below.
Given that you started with a mixture of isomers, my view is that you have a mixture of products with phenolic and acidic functionalities. As for the
smell, that could be the result of cross-reaction products between different components of the mixture - but in any case, it wouldn't be possible to
directly produce an aldehyde from phthalic acid under oxidising conditions. |