Oxidation of primary alcohols to carboxylic acids

Description: Primary alcohols treated with chromic acid will be converted to carboxylic acids.
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Notes: There are many other ways to show this transformation that amount to the same thing. Such as

• K₂Cr2O₇ / H₃O(+)
• Na₂Cr₂O₇/H₃O(+)
• CrO₃/H₂SO₄
• KCrO₄/H₃O(+)

All of these conditions generate H₂CrO₄ in the flask.

KMnO₄ will also do the same reaction.

Examples:

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.

Notes:

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