以N,N-二甲基甲酰胺为溶剂萃取精馏制备高纯度甲缩醛

摘要

The solvent for methylal production by extractive distillation was chosen according to basic selection rules. The appropriate solvent and solvent ratio were determined with Chemcad simulation and vapor-liquid equilibrium experiment. The results showed that N,N-dimethylformamide (DMF) as a solvent could eliminate the azeotropic point of the azeotrope methylal-methanol. The simulation of vapor-liquid equilibrium using UNIQUAC model for methylal-methanol system with and without DMF under atmospheric pressure were performed and the simulation results agreed well with the experimental data. Finally the separation of crude product of methylal-methanol by batch extractive distillation was performed. Under the operation conditions, the high purity product methyal of 99.9% (mass percentage) could be obtained at the top of the column .%通过溶剂选择原理粗选出萃取精馏制备甲缩醛产品的溶剂，既而通过Chemcad软件模拟和汽液平衡实验确定合适的溶剂及溶剂比。结果表明，N,N-二甲基甲酰胺(DMF)能够消除甲缩醛-甲醇共沸物系的共沸点；采用UNIQUAC模型对常压下甲缩醛-甲醇物系和加入溶剂N,N-二甲基甲酰胺的汽液平衡进行模拟，模拟结果和实验数据吻合较好。用间歇萃取精馏实验对甲缩醛粗品进行了分离，在实验条件下，可以从塔顶得到质量浓度为99.9％的高纯度甲缩醛产品。