| 摘要 |
<p>The invention provides an improved process for the manufacture of N,N,N',N'-tetraacetylethylenediamine by acetylation of N,N'-diacetylethylenediamine with acetic anhydride, by using these two starting components in a weight ratio of from 1:1 to 1:10, stopping the acetylation before attaining the reaction equilibrium between N,N'-diacetylethylenediamine and N,N,N',N'-tetraacetylethylenediamine, preferably after having attained a conversion rate of from 20 to 70 mol % of tetraacetylethylenediamine, relative to diacetylethylenediamine, purifying the reaction mixture in order to remove the dyeing impurities, and recycling to the acetylation the purified, incompletely reacted components. Purification may be carried out by vacuum distillation or by means of an adsorbent, for example bleaching earth or active charcoal. Optionally, from 0.01 to 0.3 part by weight of ketene per part by weight of diacetylethylenediamine are added to the starting components. The process may be carried out batchwise or continuously, and it gives a practically colorless product with high yield (more than 97%).</p> |
