Patent ID: 6726811
Filing Date: 2004-04-27
Classification: C07D,Y10S

Abstract:
A method of purifying N-(2-hydroxyethyl)-2-pyrrolidone which comprises distilling a liquid resulting from reacting &ggr;-butyrolactone with 2-aminoethanol, which liquid containing N-(2-hydroxyethyl)-2-pyrrolidone, compounds having lower boiling points than that of N-2-hydroxyethyl)-2-pyrrolidone, and compounds having higher boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone using a first distillation column and a second distillation column, characterized in that the liquid is distilled using the first distillation column, thereby recovering a distillate containing the compounds having lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone and N-(2-hydroxyethyl)-2-pyrrolidone as a condensate of vapor from the first distillation column top, while removing a liquid containing the compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone as a bottom liquid, and then the distillate recovered from the first distillation column is distilled using the second distillation column, thereby removing a distillate containing the compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone as a condensate of vapor from the second distillation column top, and concurrently recovering N-(2-hydroxyethyl)-2-pyrrolidone as a side cut from a position of the second distillation column higher than the bottom thereof.