Alcohols and Phenols Overview

Study Notes

Alcohols and phenols are characterized by the presence of an OH group.
If the OH group is attached to an alkyl group, it's called an alcohol.
If the OH group is attached to an aromatic system, it's called a phenol.
Alcohols and phenols are classified and named based on the structure of the alkyl or aryl group attached to the OH group.
Primary alcohols have the structure R-CH₂OH.
Secondary alcohols have the structure R₁-CH-OH-R₂.
Tertiary alcohols have the structure R₁-C-OH-R₂-R₃.

Naming follows specific rules for multiple groups or structures
IUPAC (International Union of Pure and Applied Chemistry) rules are used for naming alcohols containing more than five carbons.

Alcohols and ethers are isomers with the same molecular formula.
The boiling point of alcohols and phenols is higher than ethers due to hydrogen bonding.

Hydration of alkenes: acid-catalyzed addition of water to an alkene.
Reduction of carbonyl compounds: the addition of hydrogen to the carbon-oxygen double bond in aldehydes or ketones is called reduction, using catalysts.
Example: using platinum
Using Lithium Aluminum Hydride (LiAlH₄) is another method for reducing carbonyl compounds.

Dehydration: alcohols react with sulfuric acid to eliminate a water molecule, forming an alkene.
Oxidation: oxidation depends on the structure
Primary alcohols can be oxidized to aldehydes and then to carboxylic acids.
Secondary alcohols are oxidized to ketones.
Tertiary alcohols do not readily oxidize,

Alcohols react with carboxylic acids in the presence of a strong acid catalyst to form esters.

Oxidation reactions are important in living systems and are catalyzed by enzymes called dehydrogenases.
An example is the oxidation of malate to oxaloacetate.
The reactions often involve nicotinamide derivatives (e.g., NAD+).