Study On The Extraction Of N, N- Dimethylacetamide By Complex Extractants

N, N-dimethylacetamide is an excellent polar solvent and an important chemical raw material which has broader applications in the chemical industry. At present, solvent extraction with single extractant combined with distillation is widely used to separate N, N-dimethylacetamide from water in the industry. By using two kinds of complex extractants which consist of the main extractant dichloromethane and assist-ed extractant 2-sec-butylphenol or o-chlorophenol, namely complex extractant A and complex extractant B respectively, the extraction process of N,N-dimethylacetamide from low concentration aqueous solutions was dicussed in this paper.First single stage extraction experiment was carried out to separate N, N-dimethylacetamide from the low concentration solutions. The influence of the type and amount of assisted extractant on the extraction effect was studied. The complex extractant A consisting of 2-sec-butylphenol and dichloromethane was chosen as the final extractant. By using the UNIFAC model, the concentration of N, N-dimethyl-lacetamide in both extraction phase and raffinate phase was predicted. The result obtained by the model coincides with the experiment result roughly, which indicates that the UNIFAC model can be used to simulate the extraction results.Based on the experiments, the process of separating DMAC from the solution by using complex extractant A or dichloromethane was simulated with Aspen Plus. The influence-of extractant composition, solvent ratio and theoretical stage number on the separation effect of extraction column was investigated. The simulation results show that in the same condition, the N, N-dimethylacetamide’s extraction rate of complex extractant A is significantly higher than that of dichloromethane. Based on this, the amount of assisted extractant was optimized to obtain the relation between solvent ratio and extractant composition.