# Oxidation of toluene, ethylbenzene and styrene with potassium permanganate in acidic medium

While I was studying my organic chemistry textbook, I came across the following reactions that need more clarifications:

Oxidation of toluene (1) is the only reaction from the textbook, and I understand it.

I have a doubt about the product of ethylbenzene (2) oxidation. I have written the two products — benzoic acid (A) and 2‐phenylacetic acid (B) — which I'm not sure about. Does the ethyl substituent become a carboxylic or does it become a methyl carboxylic group?

For the oxidation of styrene (3) in addition to A and B I would propose one more product: styrene glycol (C) because I was taught that $$\ce{KMnO4}$$ oxidizes ethylene into diol. So, which of these three compounds will be the main product?

Lastly, are the products of reaction of ethylene with potassium permanganate in basic medium and in acidic medium different or the same? Please correct me if there are any errors.

• It depends on the reaction conditions. KMnO4 is a very powerful oxidant. If you run it a high temperature with concentrated acid then phenylacetic acid loses CO2 to give toluene which is then oxidised to benzoic acid. Same with styrene, under controlled conditions you can get the diol, push harder and that oxidises further. Aug 12 at 6:45
• I do not think that the mechanism is from outside in. The benzylic position is active and ketones are isolated under less forceful conditions. Glycols do form and under acidic conditions will rapidly oxidize further, not much need to push harder. Aug 12 at 18:15
• @Waylander I did some research and I guess your explanation is the correct way to understand this. Aug 13 at 12:11
• @jimchmst Thank you too for the explanation Aug 13 at 12:11