Oxidation of styrene with permanganate

My teacher told me that when we oxidise styrene with $\ce{KMnO4}$, it will stop at benzaldehyde. But I think that it will continue to go on till benzoic acid. Am I right?




In the heterogenous permanganate oxidation of styrene, that is when the reaction is performed in dichloromethane with potassium permanganate on a solid support (such as aluminium oxide), the reaction stops at the stage of the aldehyde. 


The method was published in [*Synthesis* **2001**, *11*, 1645-1648](http://dx.doi.org/10.1055/s-2001-16760) and the authors report a yield of 90% for the oxidation of styrene to benzaldehyde.


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