文献类型：专利

英文题名：Separating 1,2-propanediol involves adding ethylene glycol and 1,2-propylene glycol with entrainer dimethyl oxalate into ethylene glycol separating tower, entering top mixture into low-pressure azeotropic distillation tower

作者：SHEN R;LI W;ZHOU J;ZHENG S;SUN J

机构：[1]UNIV EAST CHINA SCI & TECHNOLOGY

申请号：CN108191608-A

申请日：2017-12-29

公开日：2018-06-22

语种：英文

收录：DERWENT

摘要：NOVELTY - Separating 1,2-propanediol involves adding ethylene glycol and 1,2-propylene glycol with entrainer dimethyl oxalate into ethylene glycol separating tower, where operating pressure of separation column is 8-10 bar, tower plate number of 60-80, reflux ratio is 12-20. The bottom of the separation tower to obtain product ethylene glycol, the top of the tower has azeotropic mixture of 1,2-propanediol and dimethyl oxalate. The top mixture is entered into low-pressure azeotropic distillation tower. The operation pressure of low-pressure azeotropic distillation tower is 1-10 bar. The tower plate number is 60-90. The reflux ratio is 8-10. The bottom of low-pressure azeotropic distillation tower to obtain 1,2-propylene glycol. The top of the tower has azeotropic mixture of 1,2-propylene glycol and dimethyl oxalate. USE - Method for separating 1,2-propanediol. ADVANTAGE - The method enables to separate 1,2-propanediol that has economic value, high purity and high yield, and reduces the equipment investment and energy consumption. DETAILED DESCRIPTION - The operation pressure of high-pressure azeotropic distillation tower is 5-30 bar. The tower plate number of 60-90. The reflux ratio is 6-20. The bottom of the high pressure azeotropic distillation column obtains dimethyl oxalate and is recycled back to the ethylene glycol separation column for use as an azeotropic agent. The top of the column is an azeotrope of 1,2-propanediol with dimethyl oxalate and is recycled back to the low pressure azeotropic distillation column. An INDEPENDENT CLAIM is included for method for using oxalate as entrainer, which involves adopting azeotropic distillation method for separating low concentration of 1,2-propylene glycol in glycol.