Pure ethyl chloride can be prepared from ethyl alcohol using

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}+{\mathrm{SOCl}}_2\to {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{Cl}+{\mathrm{SO}}_2+\mathrm{HCl};$

The byproducts are gases, they escape out leaving behind pure alkyl halide;