Pyrrolidine has been prepared from n-butylamine by heating N-chloro-N-acyl derivatives of the amine with concentrated sulfuric acid. N -chloro-N-butylacetamide underwent ring closure with the formation of pyrrolidine in SO per cent yields when heated with 95 per cent sulfuric acid for one hour at 130-140°. With 99.5 per cent acid the percentage yield was much lower. N-chloro-N-n-butyl-p-toluenesulfonamide when heated with 95 per cent sulfuric acid for thirty minutes at 140° formed pyrrolidine in 50 per cent yields. In both cases considerable amounts of n-butylamine were also formed
