Alcohols, Phenols and Ethers

Lesson

Part 1 — compounds with a C–O bond: what they are, how they are named and how they are made.

In this lesson you will

Classify and name alcohols, phenols and ethers
Describe the structure and bonding of the C–O–H and C–O–C groups
Write methods of preparing alcohols from alkenes, carbonyl compounds and Grignard reagents
Write methods of preparing phenol, including the cumene process and from diazonium salts

Table of familiar alcohols, phenols and ethers and where they are met
Compound	Where you meet it
Ethanol	Hand sanitiser, fuel blended with petrol
Methanol	Industrial solvent; poisonous to drink
Phenol	Disinfectants, plastics such as Bakelite
Glycerol	Soaps and cosmetics
Methyl tert-butyl ether	Additive in some fuels

Concept

Classification

Alcohols are mono-, di- or trihydric by the number of –OH groups, and 1°, 2° or 3° by the carbon carrying –OH. Allylic and benzylic alcohols have –OH on an sp³ carbon next to C=C or a ring. Phenols have –OH on an aromatic carbon. Ethers are symmetrical (R–O–R) or unsymmetrical (R–O–R′).

Table classifying alcohols, a phenol and an ether with examples and structures
Type	Example	Structure
Primary alcohol	Ethanol	$\ce{CH3CH2OH}$
Secondary alcohol	Propan-2-ol	$\ce{(CH3)2CHOH}$
Tertiary alcohol	2-Methylpropan-2-ol	$\ce{(CH3)3COH}$
Dihydric alcohol	Ethane-1,2-diol	$\ce{HOCH2CH2OH}$
Benzylic alcohol	Phenylmethanol	$\ce{C6H5CH2OH}$
Phenol	Phenol	$\ce{C6H5OH}$
Ether	Methoxyethane	$\ce{CH3OCH2CH3}$

Concept

Naming

Alcohols: replace the final -e of the alkane by -ol, with a locant (propan-2-ol). Phenols: named as derivatives of phenol (2-methylphenol). Ethers: alkoxyalkanes, the larger group being the parent (methoxyethane).

Table of common and IUPAC names of alcohols, phenols and ethers
Structure	Common name	IUPAC name
$\ce{CH3CH(OH)CH3}$	Isopropyl alcohol	Propan-2-ol
$\ce{(CH3)3COH}$	tert-Butyl alcohol	2-Methylpropan-2-ol
$\ce{HOCH2CH(OH)CH2OH}$	Glycerol	Propane-1,2,3-triol
$\ce{CH3C6H4OH}$ (ortho)	o-Cresol	2-Methylphenol
$\ce{C6H4(OH)2}$ (1,2)	Catechol	Benzene-1,2-diol
$\ce{C6H5OCH3}$	Anisole	Methoxybenzene
$\ce{CH3OCH2CH3}$	Ethyl methyl ether	Methoxyethane

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