离子液体对两种共沸物系汽液相平衡的研究及其模型化

发布时间：2018-05-31 04:55

本文选题：离子液体 + 汽液相平衡　；参考：《北京化工大学》2015年硕士论文

【摘要】：工业生产中,经常需要采用特殊精馏方法对存在的共沸物进行分离。近些年,绿色化学的兴起使得离子液体在萃取精馏技术中被用作萃取剂的研究得到了快速的发展。本文测定了甲醇-碳酸二甲酯(DMC)和甲醇-甲乙酮两种物系的汽液平衡(VLE)数据,并分别采用1-乙基-3-甲基咪唑三氟甲磺酸盐([EMIM]OTf)和1-丁基-3-甲基咪唑三氟甲磺酸盐([BMIM]OTf)两种离子液体作为萃取剂对两种共沸物系进行有效地分离；利用Wilson、eNRTL、NRTL及UNIQUAC四种活度系数模型对测定的VLE数据进行关联,利用UNIFAC模型对其预测。本文具体的工作为：1.汽液平衡数据的测定。在常压下,测定了二元组分甲醇-DMC和甲醇-甲乙酮物系的VLE数据；测定了三元组分甲醇-DMC-[EMIM]OTf、甲醇-DMC-[BMIM]OTf、甲醇-甲乙酮-[EMIM]OTf和甲醇-甲乙酮-[BMIM]OTf物系的VLE数据,离子液体采用0.050、0.100、0.150三个浓度系列。2.实验结论。离子液体对共沸物系有着一定的“盐效应”作用机理,本文采用的[EMIM]OTf和[BMIM]OTf对两种物系都体现出了离子液体的“交叉盐效应”；离子液体对物系的“交叉盐效应”随其浓度增加而增大；同浓度下的[EMIM]OTf和[BMIM]OTf,对两种共沸物系的分离效果都体现出了[BMIM]OTf[EMIM]OTf的规律,[BMIM]OTf在摩尔分数为10%时可打破两个物系的共沸现象；针对甲醇-DMC和甲醇-甲乙酮物系,相同浓度的三氟甲磺酸盐类离子液体对甲醇-甲乙酮共沸体系的分离效果较为显著。3.活度系数模型关联。采用Wilson、eNRTL、NRTL和UNIQUAC四种活度系数模型对两种物系的VLE数据关联,关联得到了对应模型的交互作用参数,并根据计算值与实验数据的对比给出了相应的分析。4.UNIFAC模型的关联与预测。针对工业意义较大的甲醇-DMC物系,采用UNIFAC模型对其二元及三元(含[BMIM]OTf)体系进行回归,得到模型中所需划分的基团参数,再对包含[EMIM]OTf的三元体系进行预测,活度系数的平均相对误差为5.21%。预测值接近于实验值,说明了本文回归出的-OCOO-和-[MIM]OTf基团间的交互作用参数可以用来判断具有相同基团的离子液体能否作为萃取剂。本文测定了含离子液体体系的VLE数据,采用热力学模型对实验数据进行关联与预测,得到了模型中对应的交互作用参数,为萃取精馏分离甲醇-DMC和甲醇-甲乙酮时采用离子液体作为萃取剂提供了理论支持。
[Abstract]:In industrial production, special distillation is often used to separate azeotropic compounds. In recent years, with the development of green chemistry, the research of ionic liquids used as extractant in extractive distillation technology has been developed rapidly. In this paper, the VLEE data of two systems of methanol-dimethyl carbonate (DMC) and methanol-methyl ethyl ketone (methanol-methyl ethyl ketone) have been determined. The two azeotrope systems were separated effectively by using two ionic liquids, 1-ethyl-3-methyl imidazole-trifluoromethyl sulfonate ([EMIM] OTF) and 1- Ding Ji -3-methylimidazole-trifluoromethyl sulfonate ([BMIM] OTF), respectively. The measured VLE data were correlated with four activity coefficient models (Wilsonian NRTL and UNIQUAC) and predicted by UNIFAC model. The specific work of this paper is 1: 1. Determination of vapor-liquid equilibrium data. The VLE data of binary component methanol DMC and methanol-methyl ethyl ketone system were determined at normal pressure, and the VLE data of ternary components methanol -DMC- [EMIM] OTf, methanol -DMC- [BMIM] OTf, methanol-methyl ethanone [EMIM] OTf and methanol-methyl ethanone [BMIM] OTf system were determined. The ionic liquid is 0.050 ~ 0.100 ~ 0.150, three concentration series. 2. Experimental conclusions. Ionic liquids have a certain mechanism of "salt effect" on azeotrope system. [EMIM] OTf and [BMIM] OTf used in this paper both embody the "cross salt effect" of ionic liquids. The "cross salt effect" of ionic liquids increases with the increase of their concentration, and the separation effect of [EMIM] OTf and [BMIM] OTF on the two azeotropic systems at the same concentration shows the rule of [BMIM] OTf [EMIM] OTf, and [BMIM] OTf can break the azeotropic phenomenon of the two systems when the molar fraction is 10. The separation of methanol-methyl ethyl ketone azeotropic system with the same concentration of trifluoromethylsulfonate ionic liquids was significant for methanol -DMC and methanol-methyl ethyl ketone system. The activity coefficient model is correlated. The VLE data of the two systems are correlated by using the Wilsonian NRTL NRTL and UNIQUAC activity coefficient models. The interaction parameters of the corresponding models are obtained. The correlation and prediction of UNIFAC model are given according to the comparison between the calculated values and the experimental data. For the methanol DMC system of great industrial significance, the binary and ternary systems (including [BMIM] OTF) were regressed by UNIFAC model, and the group parameters needed to be partitioned in the model were obtained, and then the ternary system containing [EMIM] OTf was predicted. The average relative error of activity coefficient is 5.21. The predicted value is close to the experimental value, which indicates that the interaction parameters between -OCOO- and [MIM] OTf groups can be used to determine whether ionic liquids with the same group can be used as extractant. In this paper, the VLE data of ionic liquid system are measured, the experimental data are correlated and predicted by thermodynamic model, and the corresponding interaction parameters in the model are obtained. It provides theoretical support for the separation of methanol-DMC and methanol-methyl ethyl ketone by extractive distillation using ionic liquid as extractant.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O642.42;TQ028.13

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