A process for the preparation and fractionation of a mixture of dimethyl ether and chloromethane with methanol as extractant

摘要

Preparation and separation of a mixture of dimethyl ether and chloromethane is effected by: (a) reacting MeOH with an excess of HCl; (b) treating the mixture obtained with an excess of MeOH and distilling in a first column with removal of water at the sump and a MeOH/Me2O/MeCl mixture at the top; (c) treating the mixture in an extractive distillation column which has MeOH added as extractant at the upper part while drawing off an MeOH/Me2O mixture at the sump and MeCl at the top; (d) distilling the MeOH/Me2O mixture in a second column with removal of MeOH at the sump and Me2O at the top; and (e) recycling part of the MeOH obtained in step (d) back to steps (a) and (b) and part back to the upper part of the extraction column as extractant.