48 E - Organic Chemistry (Mcmurry)

Question

Predict the structure of the product formed in the reaction of the organic base pyridine with the organic acid acetic acid, and use curved arrows to indicate the direction of electron flow.

Step-by-Step Solution

Answer

The product of the following reaction is:

Lewis acid and bases

Lewis acid and bases are defined by the Lewis theory of acid and base reaction as electron pair acceptor and electron pair donor, respectively. Therefore a Lewis base can donate a pair of electrons to a Lewis acid to form a product containing a covalent bond.

$A^{+}\stackrel{}{}+\stackrel{}{}{B}^{-}\stackrel{}{}\to \stackrel{}{}A-B$

      Lewis      Lewis          Coordinate

    Acid          Base         Covalent bond

 

  (Electron acceptor)   (Electron donor)    

Identify pyridine and acetic acid as Lewis acid or base

Pyridine has a non-bonding pair of electrons which it can donate to a Lewis acid. So, pyridine can act as a Lewis base

Acetic acid has an O atom that makes a polar bond to H, so it can donate H⁺. So, acetic acid can act as a Lewis base.

 

Product of the reaction

The product formation of the following reaction with curved arrows to indicate the direction of electron flow is shown below:

Here, in the above-written reaction, pyridine, which acts as a Lewis base, reacts with acetic acid, which acts as a Lewis acid, to form an acetate and pyridinium ion as a product.