Properties
Test Study Guide: -Reaction of Alcohols
-Reactions of Phenols
Ch.5 Alcohols -And More
CONCEPT SUMMARY
Alcohols and Phenols
Description and Properties
General Structure: Alcohols have the general formula ROH, where R represents an alkyl group. They are
named with the suffix -ol when they are the highest priority functional group. If not, they are prefixed with
hydroxy-.
Phenolic Structure: Phenols consist of a benzene ring bonded to a hydroxyl group (-OH). Their naming is
based on the position of the hydroxyl group relative to other substituents on the benzene ring:
a. Ortho-: Hydroxyl groups on adjacent carbons.
b. Meta-: Hydroxyl groups separated by one carbon.
c. Para-: Hydroxyl groups located on opposite sides of the ring.
Hydrogen Bonding: Alcohols exhibit hydrogen bonding due to their hydroxyl groups, which leads to higher
boiling and melting points compared to alkanes. This property also enhances their solubility in water.
Acidity of Phenols: Phenols are generally more acidic than alcohols because the aromatic ring can delocalize
the negative charge of their conjugate base, making them more stable.
Effects of Substituents on Acidity:
a. Electron-donating Groups (EDGs): Alkyl groups act as electron donors, decreasing acidity by destabilizing
negative charges.
b. Electron-withdrawing Groups (EWGs): Electronegative atoms or aromatic rings increase acidity by
stabilizing negative charges through resonance or inductive effects.
Reactions of Alcohols
Primary Alcohol Oxidation
Primary alcohols can be oxidized to aldehydes using pyridinium chloro-chromate (PCC).
Stronger oxidizing agents will further oxidize primary alcohols to carboxylic acids.
Secondary Alcohol Oxidation
Secondary alcohols can be oxidized to ketones by various common oxidizing agents.
Conversion to Mesylates and Tosylates
Alcohols can be transformed into mesylates or tosylates, enhancing their ability to act as leaving groups in
nucleophilic substitution reactions.
Mesylates: Contain the functional group -SO2CH3, derived from methanesulfonic acid.
Tosylates: Contain the functional group -SO2C6H5CH3, derived from toluenesulfonic acid.
Protection of Aldehydes and Ketones