Ethers – Detailed Explanation

Ethers are a class of organic compounds characterized by an oxygen atom connected to two alkyl or aryl groups. The general formula of ethers is R–O–R′, where R and R′ can be the same or different. Ethers are important industrially and biologically, and are less reactive compared to alcohols.

1. Classification of Ethers

A. Based on Hydrocarbon Groups

• Simple (Symmetrical) Ethers: Both groups same. Example: Diethyl ether (C₄H₁₀O)
• Mixed (Unsymmetrical) Ethers: Groups different. Example: Methyl ethyl ether

B. Based on Type of Group

• Aliphatic Ethers: Both groups alkyl. Example: Diisopropyl ether
• Aromatic Ethers: At least one aryl. Example: Anisole (C₆H₅–OCH₃)

2. Nomenclature of Ethers

A. Common System

Example names:

• CH₃–O–CH₃ → Dimethyl ether
• CH₃–O–C₂H₅ → Methyl ethyl ether

B. IUPAC System

• CH₃–O–CH₂CH₃ → Methoxyethane
• C₆H₅–O–CH₃ → Methoxybenzene (Anisole)

3. Structure of Ethers

Ethers have a bent geometry at oxygen with bond angle ~110°. C–O–C bonds are σ-bonds formed by sp³ hybrid orbitals.

4. Preparation of Ethers

• Williamson Ether Synthesis: R–O⁻ + R′–X → R–O–R′ + X⁻
• Dehydration of Alcohols: 2 R–OH → R–O–R + H₂O (with H₂SO₄, 413 K)

5. Physical Properties

• Colorless, volatile liquids
• Boiling points lower than alcohols
• Slightly soluble in water
• Good organic solvents

6. Chemical Properties

• Reaction with Acids: R–O–R′ + HI → R–I + R′–OH
• Peroxide Formation: R–O–R + O₂ → R–O–O–R

7. Uses of Ethers

• Industrial solvents
• Former anesthetic (diethyl ether)
• Perfumes & pharmaceuticals (anisole)
• Used with Grignard reagents