Method for separating water from a dilute aqueous solution of N-methylmorpholine-N-oxide, N-methylmorpholine and / or morpholine

摘要

For the removal of water from dilute aqueous solution of NMMO, N-methylmorpholine or morpholine or mixtures thereof, the solution is subjected to reverse osmosis at a pressure in excess of the osmotic pressure and probably around 40 bar and a temperature of 25 DEG C. to 75 DEG C. to form a retentate containing the amines and a permeate which is practically free from the amines. The permeate can be used as process water while the retentate can be worked up to NMMO for reuse in the cellulose solubilization process.