Carboxylic Acid Derivatives: Preparation & Reaction Charts
Understanding the reactivity and transformations of acid derivatives—Acetyl Chloride, Acetic Anhydride, Ethyl Acetate, and Acetamide—is essential for JEE, NEET, and Board exams.
Nucleophilic Acyl Substitution Reactivity
The reactivity of acid derivatives depends on the leaving group ability and resonance stabilization:
1. Reaction Chart of Acetyl Chloride ($CH_3COCl$)
Acetyl chloride is the most reactive derivative due to the excellent leaving ability of the $Cl^-$ ion. It is widely used for acetylation reactions.
High-Yield points
- Rosenmund Reduction: Hydrogenation with $Pd/BaSO_4$ (poisoned) yields Acetaldehyde.
- Reactivity: Reacts violently with water to form Acetic Acid and $HCl$.
- Friedel-Crafts Acylation: Used to prepare Acetophenone from Benzene.
2. Reaction Chart of Acetic Anhydride ($(CH_3CO)_2O$)
Acetic anhydride is a milder acetylating agent than acetyl chloride, making it safer for industrial applications like Aspirin synthesis.
Key Mechanisms
- Perkin Reaction: Reaction with aromatic aldehydes to form $\alpha,\beta$-unsaturated acids.
- Synthesis of Aspirin: Acetylation of Salicylic acid using Acetic Anhydride.
- Hydrolysis: Slowly reacts with water to form two molecules of Acetic Acid.
3. Reaction Chart of Ethyl Acetate ($CH_3COOC_2H_5$)
Esters are known for their pleasant fruity smells. Ethyl acetate is a common solvent and intermediate in various condensations.
Must-Know Reactions
- Claisen Condensation: Formation of Ethyl Acetoacetate (EAA) using Sodium Ethoxide.
- Saponification: Alkaline hydrolysis to form Sodium Acetate and Ethanol.
- Grignard Reaction: Reaction with two equivalents of RMgX yields a Tertiary Alcohol.
4. Reaction Chart of Acetamide ($CH_3CONH_2$)
Amides are the least reactive acid derivatives due to strong resonance stabilization of the lone pair on nitrogen.
Famous Named Reactions
- Hoffmann Bromamide Degradation: Reaction with $Br_2/KOH$ to form Methylamine (One carbon less).
- Dehydration: Heating with $P_2O_5$ yields Methyl Cyanide (Acetonitrile).
- Amphoteric Nature: Acts as a very weak base and a very weak acid.
Thank you sir
ReplyDelete