共沸剂对碳酸二甲酯-甲醇共沸物分离效率的影响

Effect of azeotropic agent on dimethyl carbonate-methanol azeotrope separation process

摘要:

采用正庚烷、正己烷、环己烷、1,2-二氯乙烷、四氯化碳和苯等共沸剂，较系统地考察了共沸剂及回流比对碳酸二甲酯（DMC）-甲醇（CH3OH）共沸物共沸精馏分离效果的影响。结果表明，采用共沸精馏法可以高效分离DMC-CH3OH共沸物，通过调控回流比以及共沸剂可以有效改变分离后釜液中组分的组成。采用相同共沸剂下，当回流比为7∶1和8∶1时DMC-CH3OH共沸物的分离效果较好。相同回流比7∶1下，采用不同共沸剂共沸精馏DMC-CH3OH混合物得到DMC的质量分数和收率顺序为：1,2-二氯乙烷＞四氯化碳＞环己烷＞苯＞正己烷＞正庚烷。

Abstract:

This paper systematically investigates the influence of azeotropic solvent and reflux ratio on separation efficiency of DMC-CH3OH mixture after azeotropic distillation with various solvents: n-C7H16, n-C6H14, C6H12 (hexamethylene), CH2ClCH2Cl, CCl4 and C6H6, respectively. It is experimentally proved that azeotropic distillation method is highly efficient for the separation of DMC-CH3OH mixture. The results indicate that the composition of residue can be effectively regulated by modifying azeotropic solvent and reflux ratio. For azeotropic solvents investigated, the optimal reflux ratios are 7:1 or 8:1, which can lead to higher separation efficiency for DMC-CH3OH mixture. Moreover, at the same reflux ratio (7:1), the content and yield of DMC after azeotropic distillation are dependent on different solvents as the following order: CH2ClCH2Cl > CCl4 > C6H12 > C6H6 > n-C6H14 > n-C7H16.