Question

State how the following conversions can be carried out:
(a) Ethyl chloride to Ethyl alcohol.
(b) Ethyl chloride to Ethene.
(c) Ethene to Ethyl alcohol.
(d) Ethyl alcohol to Ethane.

Answer 1

(a) Hydrolysis of ethyl chloride in the presence of an aqueous KOH gives ethyl alcohol:

$\underset{\mathrm{Ethyl}\mathrm{chloride}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}}+\underset{\left(\mathrm{aqueous}\right)}{\mathrm{KOH}}\to \underset{\mathrm{Ethyl}\mathrm{alcohol}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}}+\mathrm{KBr}$

(b) Dehydrohalogenation of ethyl chloride in the presence of alcoholic KOH gives ethene:

$\underset{\mathrm{Ethyl}\mathrm{chloride}}{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}}+\underset{\left(\mathrm{alcoholic}\right)}{\mathrm{KOH}}\to \underset{\mathrm{Ethene}}{{\mathrm{C}}_2{\mathrm{H}}_2}+\mathrm{KBr}+{\mathrm{H}}_2\mathrm{O}$

(c) Treating ethene with water in the presence of sulphuric acid gives us ethyl alcohol:

$\underset{\mathrm{Ethene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2}+{\mathrm{H}}_2{\mathrm{SO}}_4\underset{30\mathrm{atm}}{\overset{80°\mathrm{C}}{\to }}\underset{\mathrm{Ethyl}\mathrm{hydrogen}\mathrm{sulphate}}{{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{HSO}}_4}\underset{}{\overset{\mathrm{Boiling}\mathrm{water}}{\to }}\underset{\mathrm{Ethyl}\mathrm{alcohol}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}}+{\mathrm{H}}_2{\mathrm{SO}}_4$

(d) Heat ethyl alcohol with sulphuric acid to get ethene. This should be followed by its reduction in the presence of hydrogen (with a catalyst such as Ni, Pd or Pt) to get ethane.
$\underset{\mathrm{Ethyl}\mathrm{alcohol}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}}\underset{\mathrm{conc}.{\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{170°\mathrm{C}}{\to }}\underset{\mathrm{Ethene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2}\underset{∆}{\overset{{\mathrm{H}}_2/\mathrm{Ni}}{\to }}\underset{\mathrm{Ethane}}{{\mathrm{CH}}_3{\mathrm{CH}}_3}$