Question

How to convert ethanol into methanol?

Answer 1

Conversion of Ethanol to Methanol:-

Step 1: Formation of Ethanal

When the ethanol is oxidized with Potassium dichromate${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ and Sulphuric acid it produces Ethanal:

$\underset{\mathrm{Ethanol}}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{OH}}\underset{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7/{\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{\left[\mathrm{O}\right]}{\to }}\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3-\mathrm{CHO}}$

Step 2: Formation of Acetic acid

The Ethanal formed is again oxidized with Potassium dichromate${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ and Sulphuric acid to produce Acetic acid:

$\underset{\mathrm{Ethanal}}{{\mathrm{CH}}_3-\mathrm{CHO}}\underset{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7/{\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{\left[\mathrm{O}\right]}{\to }}\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3-\mathrm{COOH}}$

Step 3: Formation of Sodium acetate

This Acetic acid is then reacted with Sodium hydroxide to form Sodium acetate

$\underset{\mathrm{Acetic}\mathrm{acid}}{{\mathrm{CH}}_3-\mathrm{COOH}}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{\mathrm{NaOH}}\to \underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}$

Step 4: Formation of Methane

The Sodium acetate formed is then reacted with Sodium hydroxide and Calcium oxide to form Methane$\left({\mathrm{CH}}_4\right)$, Sodium carbonate$\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$ and Calcium

$\underset{\mathrm{Sodium}\mathrm{acetate}}{{\mathrm{CH}}_3\mathrm{COONa}}\underset{\mathrm{Soda}\mathrm{lime}}{\overset{\mathrm{NaOH}+\mathrm{CaO}}{\to }}\underset{\mathrm{Methane}}{{\mathrm{CH}}_4}+\underset{\mathrm{Sodium}\mathrm{carbonate}}{{\mathrm{Na}}_2{\mathrm{CO}}_3}+\underset{\mathrm{Calcium}}{\mathrm{Ca}}$

Step 5: Formation of Methyl chloride

The Methane formed is now reacted with Chlorine to form Methyl chloride and Hydrochloric acid

$\underset{\mathrm{Methane}}{{\mathrm{CH}}_4}+\underset{\mathrm{Chlorine}}{{\mathrm{Cl}}_2}\to \underset{\mathrm{Methyl}\mathrm{chloride}}{{\mathrm{CH}}_3\mathrm{Cl}}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}}$

Step 6: Formation of Methanol

Finally, this Methyl chloride is reacted with Potassium hydroxide to produce our required Methanol:

$\underset{\mathrm{Methyl}\mathrm{chloride}}{{\mathrm{CH}}_3\mathrm{Cl}}+\underset{\mathrm{Potassium}\mathrm{hydroxide}}{\mathrm{KOH}}\to \underset{\mathrm{Methanol}}{{\mathrm{CH}}_3\mathrm{OH}}+\underset{\mathrm{Potassium}\mathrm{chloride}}{\mathrm{KCl}}$

This conversion of Ethanol to Methanol is a 6 step reaction.