[Sis290025]

After KMnO4 is added to toluene and is refluxed, benzoic acid forms. However, after MnO2 is removed but before acidification occurs (before HCl is added to filtrate), is the benzoic acid, the product in the clear filtrate, in an aqueous form? (Did I use "aqueous" correctly? I know the product does not exist in a solid form as yet.)

Thanks.

[lavoisier]

First you should remember to mention that you haven't got just KMnO4 and PhCH3, but probably water, too.

Then I think you should write the balanced redox reaction:

a KMnO4 + b PhCH3 --> c MnO2 + d PhCOOH + ...

When you find the stoichiometric coefficients and see what is missing on the right hand side, you should understand what happens to your benzoic acid before acidifying.

Note that what changes in your PhCOOH before and after acidification is not only its physical aggregation state (solid rather than liquid), but something more important. Don't confuse solutions with liquids made of melted pure substances.

[Sis290025]

Before acidification, is the reaction as follows?

PhCH3 + 2MnO4- --> PhCOO- + 2MnO2 (precip.) + H2O + OH-

Now that I wrote the above out, I’m still confused. Did I mix up the aqueous state with the liquid state? I thought that if ions exist in water it would be labeled “aqueous.” 

I was trying to work out the reaction mechanism for the oxidation of toluene just to understand the reaction more, but I am unsure of the steps since I was following an example, the oxidation of benzaldehyde.  Instead of arriving at PhCOOH from PhCH3, I got PhCHO. How do 2 oxygen atoms replace the side chain from PhCH3? (Does the mechanism show PhCH3 oxidized to PhCHO, which is then oxidized again by MnO4- to finally get PhCOOH? I’m sorry if this is a foolish question.  ) How exactly does this mechanism look?

Thanks again.

[Sis290025]

Is there anyone at all who can help with my questions, particularly the mechanism?

Thanks again.