My questions is that do secondary alcohols react faster than primary alcohols or is it the other around? This for the oxidation of the alcohol to a ketone or an aldehyde.

This reaction is with KMnO4 with a catalyst of H2SO4 Example of 2 alcohols: butan-1-ol (primary) propan-2-ol (secondary)

I thought that secondary has a faster oxidation reaction because its carbon chain is shorter?

I was wondering if someone could provide the answer with multiple reasons?

Thanks in advance!

  • $\begingroup$ In general, primary alcohols react faster due to sterics. Exceptions may occur. $\endgroup$ – Jan Nov 7 '19 at 7:52

To reason about the kinect reaction you must consider the mechanism of the reaction. Honestly I can't say much about this reaction specificaly since the oxidation mechanism by KMnO4 is considerably complex and not much studied probably until graduate courses. I can say, however, that you can't reason about the reaction kinectics under the consideration of chain sizes. How fast a reaction will occur will depend, as said, on the mechanism and the intermediates formed (speed limiting step) during the reaction. These intermediates, in turn, will depend on the stereochemistry of the molecule and the sites where possible charges are placed. These last factors do not depend on chain size.

Hope it helps.

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