Separation of hydrogen chloride from N-alkyl-2-pyrrolidone comprises refluxing with water with overhead removal of high-purity hydrogen chloride

摘要

Separation of hydrogen chloride (HCl) from a N-alkyl-2-pyrrolidone in which the alkyl group contains 1-18 carbon atoms comprises distilling the HCl-containing N-alkyl-2-pyrrolidone at 100-220[deg]C and 50-850 hPa in the presence of water, cooling the water-HCl azeotrope at the top of the distillation column, returning the condensate to the column, withdrawing an overhead stream of gaseous HCl and withdrawing a bottoms stream of N-alkyl-2-pyrrolidone.