Alcohols

Bond angles in Alcohols

Boiling points of Alcohols

• The smaller alcohols are soluble because a larger proportion of the molecule is polar whereas the larger the molecule is, the longer the hydrocarbon chain, which is non-polar.

Different types of alcohols

Oxidation of alcohols overview

• Primary → oxidise to form aldehydes → carboxylic acids or can skip aldehydes if conditions are harsh enough.

• Secondary → oxidise to form ketones

• Tertiary → Cannot easily be oxidised

Partial oxidation of primary alcohols

Full oxidation of primary alcohols

Distillation

• Aldehydes have lower boiling points as it doesn’t have H-bonds but only v.d.w.s and permanent dipole-dipole interactions.

Reflux

• Allows you to carry out a reaction at the boiling point of the chemicals without losing any reactants or products.

Oxidation of secondary alcohols

Testing the products of oxidation

Elimination/Dehydration of Alcohols

• Primary alcohols e.g. propan-1-ol form propene and water whereas secondary alcohols e.g. butan-2-ol will form but-1-ene and but-2-ene (could exist as E/Z isomers).

• Producing alkenes from alcohols provides alternative route to polymers without using alkenes derived from oil.

• H+ comes from the acid.

Fermentation vs hydration of ethene

Acid catalysed addition mechanism for hydration of ethene.

Ethanol as a carbon-neutral biofuel