Question

How do you convert Ethanol to But-2-yne?

Answer 1

Conversion of Ethanol to But-2-yne:

Step 1: Formation of Chloroethane

The ethanol is first reacted with thionyl chloride$\left({\mathrm{SOCl}}_2\right)$ to produce chloroethane:

Step 2: Formation of Ethene

The chloroethane then formed is now reacted with alcoholic potassium hydroxide which undergoes dehydrohalogenation and produces ethene:

Step 3: Formation of 1,2-Dibromoethane

This ethene is then treated with ${\mathrm{Br}}_2/{\mathrm{CCl}}_4$which undergoes electrophilic substitution and forms 1,2-Dibromoethane:

Step 4: Formation of Ethyne

The 1,2-Dibromoethane formed is now treated with ${\mathrm{NaNH}}_2\mathrm{in}\mathrm{liq}.{\mathrm{NH}}_3$ at 196K to produce ethyne:

Step 5: Formation of Disodium acetylide

This ethyne is again treated with the same reagent (${\mathrm{NaNH}}_2\mathrm{in}\mathrm{liq}.{\mathrm{NH}}_3$) at 196K to produce disodium acetylide:

Step 6: Formation of But-2-yne

Finally, the disodium acetylide is reacted with ${\mathrm{CH}}_3\mathrm{Cl}\left(\mathrm{cross}\right)$ in order to obtain our required product But-2-yne:

Therefore, the conversion of ethanol to But-2-yne can be done using the steps.