The reactions of primary and
secondary alcohols with HCl require the presence of a catalyst, ZnCl2 With tertiary alcohols, the reaction is conducted by simply shaking the
alcohol with concentrated HCl at room temperature Constant boiling
with HBr (48%) is used for preparing alkyl bromide Good yields of
R—I may be obtained by heating alcohols with sodium or potassium
iodide in 95% orthophosphoric acid