含酸DMF溶液的综合利用

Comprehensive Utilization of Acid-containing DMF Solution

开发了一种新型绿色工艺用于精细化工行业中复杂含酸N,N-二甲基甲酰胺(DMF)溶液的脱酸回收:在含有甲酸、乙酸的DMF溶液体系中加入二甲胺,通过"一次精馏回收-连续反应-二次精馏回收"的工艺流程,实现了DMF的高效脱酸回收,同时副产工业价值更高的N,N-二甲基乙酰胺(DMAC)。对该工艺进行了小试验证与中试放大研究。中试结果表明:与不加二甲胺相比,加入二甲胺能够有效破坏羧酸与DMF间的相互作用,在一次回收塔塔顶得到质量分数95%,不含羧酸的DMF粗品,DMF回收率可达80%左右;通过二甲胺将羧酸反应转化为DMF与DMAC,可使羧酸质量分数降至1.4%,羧酸转化率可达96%;反应转化成的DMF与DMAC经过二次回收塔后,分别得到DMF质量分数47%的馏出液与质量分数97.7%的DMAC粗产品。

A novel green process was developed for the recovery of N,N-dimethylformamide(DMF) from the acid-containing DMF solution by adding dimethylamine into the acid-containing DMF system during the "primary distillation-continuous reaction-secondary distillation" process, with N,N-dimethylacetamide(DMAC) produced as by-product. The laboratory research and the pilot-scale test were carried out. The results show: dimethylamine can break the interaction between DMF and acetic acid;the crude DMF with purity of 95% and no acid was produced during the primary distillation process, and the recovery of DMF was about 80%;the acid reacted with dimethylamine, producing DMF and DMAC, with a conversion of 96%, and the concentration of acid in the mixture was reduced to 1.4% after the reaction;the distillate with 47% DMF and the residue with 97.7% DMAC were obtained from the reaction mixture in the secondary distillation process.