Question

Which of the following sets of reaction conditions would not produce an aldehyde from a primary alcohol?

a.) Oxidation with potassium dichromate

b.) Oxidation with dimethyl sulfoxide and oxalyl chloride

c.) Oxidation with pyridinium chlorochromate

d.) Oxidation with sodium hypochlorite

Answer 1

All the sets of reaction conditions would produce an aldehyde from a primary alcohol,however, that depends on certain factors.

  Oxidation with dimethyl sulfoxide and oxalyl chloride and Oxidation with pyridinium chlorochromate don`t have problem because they will not oxidize aldehydes to carboxylic acids.

In the cases of Oxidation with potassium dichromate and Oxidation with sodium hypochlorite, you get an aldehyde if you use an excess of the alcohol, and distil off the aldehyde as soon as it forms.The excess of the alcohol means that there isn't enough oxidising agent present to carry out the second stage. Removing the aldehyde as soon as it is formed means that it doesn't hang around waiting to be oxidised anyway. Then, If you use an excess of the oxidising agent , you can produce carboxilic acid.