Question

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

Answer 1

Part -1: About Deacon's process

Deacon’s process: The process to obtain chlorine gas (${\mathrm{Cl}}_2$ ) by oxidising hydrogen chloride ($\mathrm{HCl}$) gas with oxygen in the presence of Copper(II) chloride $({\mathrm{CuCl}}_2$) as a catalyst at 723 K.

Diagram of Deacon's process :

In Deacon's process, hydrogen chloride is passed into a blast furnace and burnt with air to produce chlorine and heat. It is a two-step process:

1. At elevated temperature (above 500K), $\mathrm{HCl}$ is added to the vessel containing the transition metal catalyst and after reaction, we get metal chloride.
2. Upon passing oxygen over the metal chloride, chlorine gas (${\mathrm{Cl}}_2$) evolved.

Chlorine is prepared by oxidation of hydrogen chloride gas by atmospheric oxygen in the presence of ${\mathrm{CuCl}}_2$ (catalyst) at 723K.

$\underset{\mathrm{Hydrogen}\mathrm{chloride}}{4\mathrm{HCl}\left(\mathrm{g}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\underset{723\mathrm{K}}{\overset{{\mathrm{CuCl}}_2}{\to }}\underset{\mathrm{Chlorine}}{2{\mathrm{Cl}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{water}}{2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

The chlorine gas is produced in the product.

Part-2: Reactions of chlorine with ammonia:

1. An excess of ammonia: When chlorine is reacted with an excess of ammonia, Ammonium chloride is the product, and nitrogen gas is evolved.

2. Excess of chlorine: When an excess of chlorine is reacted with ammonia, Nitrogen trichloride, and hydrogen chloride are formed.

$\underset{\mathrm{chlorine}}{3{\mathrm{Cl}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{ammonia}}{{\mathrm{NH}}_3\left(\mathrm{g}\right)}\to \underset{\mathrm{nitrogen}\mathrm{trichloride}}{{\mathrm{NCl}}_3\left(\mathrm{l}\right)}+\underset{\mathrm{Hydrogen}\mathrm{chloride}}{3\mathrm{HCl}\left(\mathrm{l}\right)}$