CHEM Chapter 8: Alcohols and Phenols

What is the difference between alcohols and phenols?

Alcohols have OH on sp³ C; Phenols have OH on sp² C (aromatic ring).

How do you name alcohols when -OH is attached to a chain or ring?

Number the chain or ring to give -OH the lowest possible number. For multiple OH groups, use -diol, -triol, etc.

What physical properties do alcohols have?

They are polar, have high boiling points due to hydrogen bonding, and are soluble in polar solvents.

Why do small alcohols dissolve in water?

They form hydrogen bonds and are polar.

What does 'amphoteric' mean in terms of alcohols?

Alcohols can act as both acids and bases.

What are alkoxides and how are they made?

Alkoxides are strong bases formed by reacting alcohols with alkali metals.

What reactions replace OH with halogen in alcohols?

SN1 for tertiary alcohols, SN2 for primary alcohols. OH becomes water, a good leaving group

What is dehydration of alcohols and which mechanism occurs?

Removal of water to form alkene: E1 for tertiary, E2 for primary alcohols.

What does Zaitsev's rule state?

The more substituted alkene (major product) is favored.

What is Jones Reagent and what does it do?

CrO3 in H2SO4 and acetone; oxidizes primary alcohols to acids, secondary to ketones.

What does PCC do?

PCC oxidizes primary alcohols to aldehydes and secondary to ketones without further oxidation.

What are the three main ways to synthesize alcohols?

SN1/SN2 substitution, hydration of alkenes, reduction of aldehydes/ketones.

What reducing agents convert carbonyls to alcohols?

H2/Pd or Pt, NaBH4 (mild), LiAlH4 (strong).

What's the difference between NaBH4 and LiAlH4?

NaBH4 is selective for carbonyls; LiAlH4 is stronger and less selective.

What's the hydration reaction difference in alcohol synthesis

Oxymercuration gives Markovnikov product; hydroboration gives anti-Markovnikov product.

How does hydroboration-oxidation work?

BH3 adds across double bond (syn); oxidized with H2O2/NaOH to give anti-Markovnikov alcohol.

What is a phenol

OH on aromatic ring; more acidic due to resonance stabilization of phenoxide ion.

What increases phenol acidity?

Electron-withdrawing groups stabilize phenoxide ion.

What do phenols oxidize into?

Quinones, which act as redox agents.

What is a thiol and how is it different from an alcohol

Contains -SH; lower boiling point, stronger acid, smells bad, oxidizes to disulfides

What reactions do thiols undergo

Nucleophilic substitution, oxidation to disulfides (RSSR)