C2 – Alcohol

There are three different types of Alcohol molecules –
1. Primary Alcohol; is when the -OH is at the end of the chain.

2. Secondary Alcohol; is when the -OH group is attached to a carbon atom bonded to two alkyl groups.

3. Tertiary Alcohol; is when the -OH group is attached to a carbon atom bonded to three alkyl groups.

Combustion and Oxidation of alcohols

In a good supply of oxygen, alcohols burn completely to form carbon dioxide and water –
C₂H₅OH(l) + 3O₂ – 2CO₂(g) + 3H₂O(l)

Oxidation of alcohols

• Primary alcohol 

 

Figure 1 shows how alcohol forms aldehyde under distillation*.

Figure 2 shows how alcohol froms carboxylic acid under reflux**.

**Reflux is the continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents of the flask boiling dry.

*Distillation apparatus

 

**Reflux apparatus

 

• Secondary alcohol

 

Secondary alcohols are oxidised by acidified dichromate ions to produce ketones.

• Tertiary alcohol 

Tertiary alcohols are resistant to oxidation as the carbon atom is already bonded to three other alkyl groups.