| 摘要 |
A method of producing purified dimethylformamide from a feed mixture 20 comprising dimethylformamide and hydrogen chloride, comprising: distilling the feed mixture to afford a more volatile fraction and a less volatile fraction (the more volatile fraction having a lower HCl content than the less volatile fraction), and collecting the more volatile fraction, at least a portion of which affords a purified dimethylformamide product that is lower in hydrogen chloride content than the feed mixture. The more volatile fraction boils at a lower temperature and is collected as overhead vapour 24 whilst the less volatile fraction boils at a higher temperature and can be collected as the bottoms 26 of the distillation process in liquid form. The distillation column 28 may consist of an upper rectifying and a lower stripping section and the feed mixture 20 may be introduced to the middle of the column 28 between the rectifying and stripping sections. Preferably the distillation column is a packed column. The purified DMF 24 may be cooled and the condensed liquid collected in vessel 32. The feed mixture may be a non-aqueous, unquenched stream from a chlorination reaction of a sucrose-6-acylate to form a sucralose-6-acylate. |
