Oxidation Reduction Reaction in Organic Chemistry
In inorganic chemistry, oxidation means losing electrons, and reduction means gaining electrons. But in organic chemistry, the meaning is slightly different:
- Oxidation = loss of hydrogen, gain of oxygen, or gain of halogen.
- Reduction = gain of hydrogen, loss of oxygen, or loss of halogen.
Oxidation is written as [O] and reduction is written as [H].
Example: Ethanol → Acetaldehyde → Acetic acid (oxidation) Reverse reactions = reduction.
Oxidizing Agents
These are chemicals that remove hydrogen or add oxygen to an organic compound.
Reducing Agents
These are chemicals that add hydrogen or remove oxygen from an organic compound.
Oxidation Reactions
1. Oxidation of Alkenes
Alkenes can be oxidized in different ways:
Formation of Epoxides
Alkenes react with peracids to form epoxides (cyclic ethers).
Formation of Carboxylic Acids and Ketones
Strong oxidizing agents convert alkenes into acids and ketones.
2. Syn-Hydroxylation of Alkenes
Both –OH groups add on the same side of the alkene to form syn-diols.
3. Anti-Hydroxylation of Alkenes
–OH groups add on opposite sides to form anti-diols.
4. Oxidative Cleavage of Diols
Syn-diols break to form aldehydes, ketones, or acids.
5. Ozonolysis of Alkenes
Breaks the double bond to form aldehydes and ketones.
6. Oxidation of Alkynes
Alkynes form diketones or acids depending on reagent strength.
7. Ozonolysis of Alkynes
Produces carboxylic acids.
8. Oxidation of Primary Alcohols
Primary alcohols can form:
- Aldehydes
- Carboxylic acids
9. Oxidation of Secondary Alcohols
Secondary alcohols oxidize to ketones.
10. Oxidation of Aldehydes
Aldehydes easily oxidize to carboxylic acids.
11. Baeyer–Villiger Oxidation
Converts ketones or aldehydes into esters or acids.
Reduction Reactions
1. Reduction of Alcohols via Tosylates
Alcohols → Tosylates → Alkanes
2. Reduction of Alkyl Halides
Alkyl halides convert to alkanes.
3. Reduction of Organometallic Reagents
Also produces alkanes.
4. Reduction of Aldehydes and Ketones
Two common methods:
- Catalytic hydrogenation → alcohols
- Hydride reduction (NaBH₄, LiAlH₄) → alcohols
5. Clemmensen Reduction
Reduces carbonyl groups to alkanes using Zn-Hg/HCl.
6. Wolff–Kishner Reduction
Reduces carbonyls to alkanes under strong base and heat.
7. Reduction of Oximes and Imines
Produces amines.
8. Reduction of Carboxylic Acids
Forms primary alcohols.
9. Reduction of Acid Chlorides
Can form:
- Aldehydes
- Primary alcohols
10. Reduction of Esters
Forms primary alcohols or aldehydes depending on reagent.
11. Reduction of Amides, Azides & Nitriles
These convert into amines.
Detailed Notes:
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