In the oxidation of the side chain in toluene with potassium permanganate and water as the reagents, does the acidity increase as the redox reaction is carried out?
Yeah. Thats it. I don't remember the exact mechanism, but I think MnO4- forms a closed chain which is replaced by -OH groups. Since a carbon atom cannot have more than 2 -OH groups at the same time, one pair of -OH molecules give water and a =O at that position. So the three hydrogens are replaced by -OH, two of which leave as water and one of the oxygens of the two remains as a =O, hence your -COOH.Do you know what kind of undesired product might form in this reaction? Would it be distinguishable from the crystallized benzoic acid?
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?
I tried using a search engine, but I mostly get reaction equations and not a mechanism or published papers that you must have an account for.
I also have another question pertaining to this redox reaction.
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.)
This the the equation before acidification:
PhCH3 + 2MnO4- --> PhCOO- + 2MnO2 (precip.) + H2O + OH-
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 believe the balanced theoretical equation is:Even though the reaction mixture occurs under basic conditions, the reaction mixture's pH still decreases as the redox reaction transpires, right?
The oxidation produces a molecule of benzoate and a molecule of hydroxide. What will the pH do?So the pH actually does increase? (It's only after acidification, not oxidation, that the pH decreases?)
Write out the half reaction for that transformation. Pay attention to the oxidation state of manganese.In the theoretical equation, doesn't the MnO4 get reduced to MnO2?