Oxidation of primary alcohols to carboxylic acids
Description: Primary alcohols treated with chromic acid will be converted to carboxylic acids.
Notes: There are many other ways to show this transformation that amount to the same thing. Such as
- K2Cr2O7 / H3O(+)
All of these conditions generate H2CrO4 in the flask.
KMnO4 will also do the same reaction.
Notes: Note the different reaction conditions here that do the exact same reaction.
Mechanism:The mechanism is not generally considered important for the purposes of Org 1/ Org 2, but one is depicted here. It’s a long mechanism, and there are a huge number of different ways to to depict the different protonation and deprotonation events.
The key here is that Cr is a good leaving group on O, and a base can remove the adjacent proton and perform an elimination reaction. This has to happen twice: once on the primary alcohol, and again on the aldehyde hydrate.