Question

how to convert ethanol into but-2-yene?

Answer 1

Ethanol can be converted to but-2-yne as follows:

$$\begin{gathered} C_2{H}_{5}OH\stackrel{conc.H_{2}S{O}_4}{\to }{C}_2{H}_4+B{r}_2\stackrel{CC{l}_4}{\to }BrC{H}_{2}C{H}_{2}Br+2NaN{H}_2\to C_2{H}_2+2NaN{H}_2/2C{H}_{3}I\to C{H}_{3}C\equiv C-C{H}_3 \\ EthanolEthene1,2dibromoethaneEthyneBut-2-yne \end{gathered}$$