Disproportionation

In the chemical reaction of disproportionation, synonym: dismutation an element occurs as part of a redox reaction at the same time as the oxidizing agent and the reducing agent, so that it beforehand in an average oxidation state, after partly in a present partly in a lower oxidation state higher and. The atoms are thus partly oxidized and partly reduced. The opposite case is called comproportionation or synproportionation.

Examples

An example is the reaction of chlorine in sodium hydroxide solution. In this case, one of the two chlorine atoms of the chlorine molecule is reduced to the oxidation state 0 with chloride ion to the oxidation number I, and the other chlorine atom is oxidized to the oxidation state I ( hypochlorite ion ).

A practical example is the water treatment in swimming pools. With the introduction of chlorine in water forms depending on the pH balance of chlorine, hypochlorous acid and hydrochloric acid.:

Depending on the pH, hypochlorous acid dissociates partially oxonium and hypochlorite ions:

As another example, the following is mentioned:

Radical disproportionation

A special case is the radical disproportionation in organic chemistry.

Cannizzaro reaction

In the Cannizzaro reaction disproportionate aldehydes which have a hydrogen atom in α -position to the aldehydic carbon atom in the presence of strong bases, such as concentrated sodium hydroxide solution. As an oxidation product is formed, the appropriate salt of a carboxylic acid, as a reduction product of the alcohol.

However, an α - hydrogen atom in the aldehyde present, the aldol reaction is preferred.