加盐萃取精馏条件对乙腈回收的影响

Effect of Salt-adding Extractive Distillation Conditions on Acetonitrile Recovery

为了从制药车间生产中回收的乙腈回收无水乙腈,研究了不同浓度的醋酸钾-乙二醇、氯化钙-乙二醇、醋酸钾-氯化钙-乙二醇体系对乙腈-水体系精馏分离效果的影响,并考察了回流比、溶剂比以及溶剂和含水乙腈流速等操作参数对乙腈-水体系精馏分离效果的影响,开发了加盐萃取精馏制备无水乙腈和溶剂回收为一体的无水乙腈回收体系。结果表明,以乙二醇-醋酸钾-氯化钙体系作为萃取剂,当醋酸钾和氯化钙的浓度均为0.05g/mL,溶剂比为1.2,回流比为2.0,萃取剂流速为1.0mL/min,乙腈流速为1.2mL/min时,可以从塔顶得到质量分数大于99.8%的无水乙腈。

In order to recover anhydrous acetonitrile from acetonitrile recovered in pharmaceutical workshop,the effects of different concentration of potassium acetate-ethylene glycol,calcium chloride-ethylene glycol,potassium acetate-calci um chloride-ethylene glycol system on the distillation separation efficiency of acetonitrile-water system were studied.The effects of reflux ratio,solvent ratio,solvent and flow rate of water-containing acetonitrile on the distillation separation effi ciency of acetonitrile-water system were investigated.An anhydrous acetonitrile recovery system which combines the prepa ration of anhydrous acetonitrile by salt-adding extractive distillation and solvent recovery was developed.The results showed that when the concentration of potassium acetate and calcium chloride was 0.05 g/mL,the solvent ratio was 1.2,the reflux ratio was 2.0,the flow rate of extractant was 1.0 mL/min,and the flow rate of acetonitrile was 1.2 mL/min,anhydrous acetonitrile with mass fraction over 99.8%could be obtained from the top of the tower.