3.3.5.2 Oxidation of alcohols

Question 1

What is needed for an oxidation to take place with an alcohol?

Answer 1

Acidified potassium dichromate
K2Cr2O7

Question 2

What is the reaction that occurs in the oxidation of alcohols (equation)?

Answer 2

14H+ + Cr2O7- + 6e- -> Cr3+ + 7H2O

Question 3

Describe the oxidation of primary alcohols

Answer 3

In the presence of [O], they become oxidised to produce aldehydes. They can be further oxidised to form carboxylic acids

Question 4

How can we get the aldehyde only from primary alcohols?

Answer 4

Use excess of alcohol and distillation, so that the aldehyde can be distilled as soon as it is formed

Question 5

What is reflux?

Answer 5

The continuous boiling and condensing of the reaction mixture

Question 5

How can we get the carboxylic acid only from primary alcohols?

Answer 5

Excess of oxidising agent (K2Cr2O7) and reflux gently

Question 6

Describe the oxidation of secondary alcohols

Answer 6

Secondary alcohols can be oxidised to ketones only - there is no further oxidation
- requires excess of acidified K2Cr2O7 oxidising agent and reflux gently

Question 7

Describe the oxidation of tertiary alcohols

Answer 7

Do not undergo oxidation