Question

Write chemical equations of five methods of preparation of Carboxylic acid.

Hint:

Easy trick: Alcohol → Aldehyde → Acid; Nitrile/ester → Hydrolysis → Acid; Grignard + CO\(_2\) → Acid.

Answer 1

Carboxylic acids can be prepared by several methods. The five important methods are: Method 1: Oxidation of Primary Alcohols.
\[ R-CH_2OH \;\xrightarrow{[O]}\; R-COOH \] Method 2: Oxidation of Aldehydes.
\[ R-CHO \;\xrightarrow{[O]}\; R-COOH \] Method 3: Hydrolysis of Nitriles.
\[ R-CN + 2H_2O \;\xrightarrow{H^+ / \Delta}\; R-COOH + NH_3 \] Method 4: Carbonation of Grignard Reagents.
\[ R-MgX + CO_2 \;\xrightarrow{H_3O^+}\; R-COOH \] Method 5: Hydrolysis of Esters.
\[ R-COOR' + H_2O \;\xrightarrow{H^+ / \Delta}\; R-COOH + R'-OH \]
Summary Table:
\begin{center} \begin{tabular}{|c|l|l|} \hline Method &
Reaction &
Product
\hline 1 & \(R-CH_2OH \;\xrightarrow{[O]}\; R-COOH\) & From Primary Alcohol
\hline 2 & \(R-CHO \;\xrightarrow{[O]}\; R-COOH\) & From Aldehyde
\hline 3 & \(R-CN + 2H_2O \;\xrightarrow{H^+}\; R-COOH + NH_3\) & From Nitrile
\hline 4 & \(R-MgX + CO_2 \;\xrightarrow{H_3O^+}\; R-COOH\) & From Grignard Reagent
\hline 5 & \(R-COOR' + H_2O \;\xrightarrow{H^+}\; R-COOH + R'-OH\) & From Ester
\hline \end{tabular} \end{center} Conclusion:
Carboxylic acids can be synthesised by oxidation, hydrolysis, and carbonation reactions, making them versatile in both laboratory and industry.