Question

How will you bring about the following conversion?

Ethanol to but-1-yne

How the following conversion can be carried out?

Ethanol to but-1-yne

Answer 1

\[\ce{CH3CH2OH ->[SOCl2, pyridine][-SO2, -HCl] \underset{chloroethane (A)}{CH3CH2 - Cl}}\]

\[\ce{HC ≡ CH + NaNH2 ->[liquid NH3,196 K] \underset{sodium acetylide (B)}{HC ≡ C^-Na^+}}\]

\[\ce{A + B -> \underset{but-1-yne}{CH3CH2-C} ≡ CH + NaCl}\]

Answer 2

\[\ce{2CH3CH2OH + SOCl2 -> 2CH3CH2Cl + SO2\uparrow + HCl\uparrow}\]

\[\begin{array}{cc}
\ce{CH3CH2Cl ->[alc{.} KOH/\Delta] CH2 = CH2 ->[Br2/CCl4]CH2 - CH2 ->[alc{.} KOH/\Delta] HC ≡ CH ->[NaNH2][liq{.} NH3, 196 K] HC ≡ \overset{\ominus}{C}\overset{\oplus}{N}a}\\
|\phantom{...........}|\phantom{.....}\\
\ce{Br}\phantom{........}\ce{Br}\phantom{....}\\
\end{array}\]

\[\ce{CH3 - CH2 - Cl + N\overset{+}{a}\overset{\oplus}{C} ≡ CH -> \underset{But-1-yne}{CH3 - CH2 - C ≡ CH}}\]

Answer 3

\[\ce{\underset{Ethanol}{CH3 - CH2 - OH} ->[HBr] CH3 - CH2 - Br ->[HC ≡ C- Na+] \underset{But-1-yne}{CH3 - CH2 ≡ CH}}\]