Problem

The saponification of 18O-labeled ethyl propanoate was described in Section 20.9 as one of...

The saponification of 18O-labeled ethyl propanoate was described in Section 20.9 as one of the significant experiments that demonstrated acyl–oxygen cleavage in ester hydrolysis. The 18O-labeled ethyl propanoate used in this experiment was prepared from 18O-labeled ethyl alcohol, which in turn was obtained from acetaldehyde and 18O-enriched water.

Write a series of equations showing the preparation of from these starting materials.

Step-by-Step Solution

Solution 1

Saponification is the alternate name for ester hydrolysis, that yields back alcohol and acid. It is called saponification because of the fact that, soaps are made by ester hydrolysis of fats.

During esterification, the alcoholic oxygen is retained in the ester.

Ethyl alcohol containing , can be synthesized from acetaldehyde by hydration using , in acidic medium. This forms a gem diol as shown.

on reduction with , yields .

The final step is an esterification reaction between propanoic acid and ethan(18O)ol, to yield

Since, the alcoholic oxygen is retained in the ester, the final product formed is .

Therefore, the final product formed is CH3CH2COO18CH2CH3.

Add your Solution
Textbook Solutions and Answers Search