Colourless tetra:acetyl-ethylene di:amine prepn. - by di:acetyl ethylene di:amine acetylation with acetic anhydride opt. with ketene addn.

摘要

Prepn. of N,N,N',N'-tetraacetyl-ethylene diamine (II) by acetylating N,N'-diacetyl-ethylene diamine (I) with acetic anhydride at 120-170 degrees C is carried out as follows. (I) and (II) are charged in wt. ratio 1:1 to 1:10 esp. 1:1 to 1:2.5, pref. with the addn. of 0.01-0.3 pts. wt. ketene based on (I). Acetylation is interrupted before establishing reaction equilibrium between (I) and (II). The brown reaction mixt. is purified to remove colouring contaminants, before or after separating (II) by crystallisation. The purified and recovered reaction components which are incompletely converted to (II) are recycled to acetylation. (II) is a perborate activator in detergent compsns. Colourless (II) is obtd. in yields of >97%. Ketene addn. reduces reaction time and increases space-time yield.