Chapter 20.4, Problem 1RQ

Interpretation Introduction

Interpretation :

The way, how the type of alcohol affects the product formed should be explained.

Concept Introduction :

In the alcohol oxidation reactions, the solutions of sodium or potassium dichromate acidified with dilute sulfuric acid are used as an oxidizing agent. The dichromate ions are reduced to the chromate ions by the oxidation process. There are various types of alcohols are present such as primary alcohol, secondary alcohols and tertiary alcohols.

Answer to Problem 1RQ

The primary alcohols are oxidized to the carboxylic acids or aldehydes while the secondary alcohols are oxidized to the ketones. But tertiary alcohols are not oxidized.

Explanation of Solution

• Based on the reaction conditions, the primary alcohols ae oxidized to either aldehydes or carboxylic acids. Firstly, the alcohol is oxidized to an aldehyde which is then further oxidized to the formation of carboxylic acid. If an excess amount of the alcohol is used, then the aldehydes is obtained which means that the there is not enough oxidizing agent for the occurring the second stage and removing the aldehydes as soon as it is formed.
• In the case of secondary alcohols, ketones are formed due to the oxidation of the secondary alcohols. By changing the reactions conditions, there is no effect of it on the product formation.
• Tertiary alcohols are not oxidized by the oxidizing agent.

Conclusion

Hence, aldehydes are produced due to the oxidation of primary alcohols while ketones are produced due to the oxidation of the secondary alcohols.