Question

How is chlorine prepared in the deacon’s process?

Answer 1

Hint: The process that produces chlorine gas from gaseous hydrogen chloride in the presence of transition metal oxide as an efficient catalyst at moderate temperature and without the volatilization of the catalyst is known as Deacon’s process.

Complete step by step answer:
In 1868, Deacon developed a process by which chlorine is produced by oxidation of gaseous $HCl$ with $O_2$ in the presence of a $Cuc{l}_2$catalyst. The chemical equation for this process is given below:
$HCl(g)+{\displaystyle \frac{1}{4}}{O}_2\stackrel{Cuc{l}_2,723K}{\to }{\displaystyle \frac{1}{2}}{H}_{2}O(g)+{\displaystyle \frac{1}{2}}C{l}_2(g)$.
This an overall exothermic process and also fast. The process consists of two-step:
A chloridizing step in which the $HCl$ is contacted with the catalyst at the elevated temperature. In this step, there is a conversion of transition metal oxide to transition metal chloride with the elimination of water.
An oxidation step in which the transition metal chloride formed in step 1 is contacted with the source of oxygen. And there is an evolution of chlorine gas and transition metal chloride is reconverted to transition metal oxide.
Several problems are associated with Deacon’s process. The temperature of the process reduces the equilibrium constant for the conversion of the $HCl$ thereby reducing the yield. And also at elevated temperature above ${675}^{\circ }K$, the catalyst’s activity rapidly decreases, due to the volatilization of the $CuC{l}_2$.

Note:
The deacon’s process is now outdated technology. Most of the chlorine is produced by using electrolytic processes. The chlorine produced by the above process is used to make polyvinyl chloride (PVC), air conditioner refrigerants, lubricants, plastic foams, insecticides, and household bleaching agents, etc.