[shafaifer]

Can 2-methylbutanoic acid lose a butyl group or can it lose an ethyl group and afterwards an ethyl group again?

Best regards

[Bidagdha_TADIR]

My teacher taught us that fragmentation pattern of carboxylic acid dictates -

[RCH₂COOH]⁺·     [RCH₂CO]⁺ + ·OH

[RCH₂COOH]⁺    RCH₂⁺  +   ·COOH

[RCH₂COOH]⁺     RCH₂·  +   [COOH]⁺

[RCH₂COOH]⁺     [CH₂=C(OH)₂]⁺ +  alkene (when γ hydrogen is available)

So, in my opinion there is no chance to loose ethyl group. It will lose butyl group.