Question

Describe with suitable diagram the Deacon process of manufacture of chlorine. Write its reaction with ammonia.

Answer 1

Deacon process is a method of obtaining chlorine gas by passing oxygen/air and hydrogen chloride gas over a heated catalyst (such as copper chloride).

It is a two step process:

1. At elevated temperature (about 500 K), $HCl$ is added to the vessel containing the transition metal catalyst as metal oxide. The metal oxide gets converted to metal chloride with the elimination of water.

2. Upon passing oxygen over the metal chloride (at temperature atleast 573 K), $C{l}_2$ gas evolves and reconverts the metal chloride to its oxide.

Overall reaction:

$4HCl+O_2\stackrel{catalyst}{\to }2H_{2}O+2{Cl}_2$

Various catalysts can be used such as: $Mn{O}_2,C{o}_2{O}_3,NiO$ etc.

Reaction of chlorine with ammonia:

1. excess of ammonia:

$3{Cl}_2+8N{H}_3\to 6N{H}_{4}Cl+N_2\uparrow$

2. Excess of chlorine:

$3{Cl}_2+N{H}_3\to \underset{explosive}{N{Cl}_3}+3HCl$