Alcohols

What is an alcohol?

• organic compound

• has one or more hydroxyl groups (–OH) attached to a saturated carbon atom

What is the general formula for a simple alcohol?

• R–OH

• R is an alkyl group

How are alcohols different from phenols?

• Alcohols: have –OH on an alkyl group

• Phenols: have –OH on an aromatic ring.

Give two examples of alcohols.

Methanol (CH₃OH) and Ethanol (CH₃CH₂OH).

Are alcohols polar or non-polar?

• Polar, due to the O–H bond

• can hydrogen bond

How are alcohols classified?

• how many carbon atoms are attached to the carbon bearing the –OH

• Primary (1°): R–CH₂–OH

• Secondary (2°): R₂CH–OH

• Tertiary (3°): R₃C–OH

What is the IUPAC suffix for naming alcohols?

-ol.

Example: Propane → Propanol.

What happens when a primary alcohol is oxidized?

• It forms an aldehyde

  • then further oxidation gives a carboxylic acid

What happens when a secondary alcohol is oxidized?

forms a ketone

Can tertiary alcohols be oxidized easily?

• No

• the carbon with the –OH group has no hydrogen atoms to remove

What type of reaction forms an alcohol from an alkene?

• Hydration: Alkene + H₂O → Alcohol

• (with acid catalyst)

How does the boiling point of alcohols compare to alkanes?

Alcohols have higher boiling points due to hydrogen bonding.

What is a dehydration reaction in alcohols?

• Removal of water (H and OH) to form an alkene

• often using heat and acid.

What happens when an alcohol reacts with a carboxylic acid?

• It forms an ester and water

• (esterification)

What is Lucas' test, and what does it distinguish?

• A test using HCl + ZnCl₂

• identify primary, secondary, and tertiary alcohols based on 2wsreactivity

• (tertiary reacts fastest).

What are the physical properties of an alcohol?

• BP ↑ b/c of hydrogen bonding

• molecules w more than one hydroxyl group show greater degrees of hydrogen bonding

  • ↑ branches = ↑ BP