Preparation of Carbonyl Compounds

Welcome and Introduction

• Hello everyone! Welcome to today's lecture on carbonyl compounds.
• We will primarily focus on aldehydes and ketones.

What are Carbonyl Compounds?

• Carbonyl Compounds: Aldehydes and Ketones
• Formula: R-CHO (Aldehyde), R-CO-R' (Ketone)

Preparation Methods

Oxidation of Alcohols

• Primary Alcohol → Aldehyde (R-CH2OH → R-CHO)
• Secondary Alcohol → Ketone (R2CHOH → R2C=O)
• Tertiary Alcohol → No Reaction
• Reagents: PCC, Chromium Oxide, Copper (830°C)

Selective Oxidation

• Using KMnO4, MnO2
• Only aldehyde from MnO2 (to prevent higher oxidation)

Dehydration of Alcohols

• 3° Alcohols → No Reaction

Properties of Alcohols

• 1° Alcohol: Forms Aldehyde
• 2° Alcohol: Forms Ketone
• 3° Alcohol: No Reaction

Mechanisms and Important Reactions

Reduction of Acid Chlorides

• Reduction of acid chlorides to form aldehydes
• Reagents: Hydrogen Peroxide, PDC

Stephen Reduction

• Reduction of Nitriles: Obtaining aldehydes from nitriles
• Reagents: SnCl2/HCl

Cannizzaro Reaction

• Both reduction and oxidation of non-alpha hydrogen aldehydes
• Example: Formaldehyde

Hydroxylation Reaction

• Oxidation of alkenes via catalysis
• Product: Diols

Hydroxylation of Alkenes

• Radical oxidation of alkenes
• Product: Aldehydes and Ketones

Other Important Reactions

Stephen Reduction

• Reduction of nitriles
• Product: Aldehyde
• Reagents: SnCl2/HCl

Pinacol Pinacolone Rearrangement

• Rearrangement of 1,2-diols
• Product: Ketones

Friedel Crafts Acylation

• Formation of ketone in benzene ring
• Reagents: Acyl chloride, Alkyl chloride

Hell-Volhard-Zelinsky Reaction

• Formation of alpha-halogen acids by reacting carboxylic acids with hydroxylamine

Tests for Carbonyl Compounds

Tollens Test

• Aldehydes: Silver mirror production
• Ketones: No reaction

Fehling's Solution Test

• Aldehydes: Red-brown precipitate
• Ketones: No reaction

Iodoform Test

• For methyl ketones
• Formation of white precipitate