离子液体用于乙酸甲酯与甲醇共沸体系的分离行为研究

发布时间：2018-03-03 05:38

本文选题：乙酸甲酯　切入点：甲醇　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：乙酸甲酯-甲醇作为聚乙烯醇生产工业中的典型共沸物,如果使用普通的精馏方法存在能耗高、效果差的特点。目前工业上常用萃取精馏技术,其关键是萃取剂的选择,而采用的有机溶剂又存在着高挥发、用量大等弊端,所以迫切需要寻找一种新型的能取代传统有机溶剂的萃取剂。离子液体作为一种绿色溶剂具有不挥发、选择性强等特点,具有显著的盐析或盐溶效应、易于回收利用等等特点而得到广泛关注。本文合成了三种离子液体,即[AMIM][DAP],A分别对应着CH3、 C2H5以及C4H9,名称为1-烷基-3-甲基咪唑二烷基磷酸盐。将这三种离子液体应用到乙酸甲酯与甲醇物系的分离中,测量了等压条件下二元体系与三元体系的实验数据,考察了其分离乙酸甲酯与甲醇共沸体系的能力。实验测定了等压下的二元体系包括乙酸甲酯-甲醇、离子液体与单一组分(乙酸甲酯或甲醇)的汽液平衡数据,可以得出,随着离子液体占整个体系的比例增大,乙酸甲酯和甲醇两组分各自的活度系数分别呈现不同的变化趋势,前者不断增大,而后者与之相反。乙酸甲酯活度系数的增加幅度与离子液体之间存在着[MMIM][DMP][EMIM][DEP][BMIM][DBP]的关系；甲醇活度系数的减小幅度与离子液体之间呈现出了与上述相反的关系。实验测定了等压下三元体系乙酸甲酯-甲醇-离子液体的数据,可以得出,当实验设定的摩尔浓度为0.05时,乙酸甲酯与甲醇的共沸点便己完全消失,此时在体系的整个浓度区间里乙酸甲酯的相对挥发度计算出来都是超过1的。离子液体分离乙酸甲酯与甲醇共沸体系的能力是：[MMIM][DMP] [EMIM][DEP] [BMIM][DBP]。二元和三元体系可以对比使用e-NRTL模型关联得到的结果与实验计算得到的结果求出相对偏差最大值,可得到结果分别为4.483%,4.801%。将关联得到的结果与实验直接计算得到的结果相对比,证明了e-NRTL热力学模型可以获得理想的结果。实验结果证明,三种离子液体都能很好的应用到共沸物乙酸甲酯与甲醇的分离中去。
[Abstract]:Methyl acetate-methanol as a typical azeotrope in polyvinyl alcohol production industry, if ordinary distillation methods have the characteristics of high energy consumption and poor efficiency, the selection of extractant is the key to the extraction distillation technology commonly used in industry. However, the organic solvent used has many disadvantages, such as high volatilization and large amount of solvent, so it is urgent to find a new extractant that can replace the traditional organic solvent. As a green solvent, ionic liquid has the characteristics of non-volatilization, strong selectivity and so on. Three kinds of ionic liquids have been synthesized in this paper because of their remarkable salting-out or salinization effect, easy to recycle and so on. That is, [AMIM] [DAP] A corresponds to Ch _ 3, C _ 2H _ 5 and C _ 4H _ 9 under the name of 1-alkyl-3-methyl imidazole dialkyl phosphate respectively. The three ionic liquids were applied to the separation of methyl acetate from methanol, The experimental data of binary system and ternary system under isobaric pressure were measured, and the ability of separating methyl acetate from methanol azeotropic system was investigated. From the vapor-liquid equilibrium data of ionic liquids and mono-component (methyl acetate or methanol), it can be concluded that the activity coefficients of methyl acetate and methanol show different trends with the increase of the proportion of ionic liquids to the whole system. The former is increasing, while the latter is opposite. There is a relationship between [MMIM] [DMP] [EMIM] [DEP] [BMIM] [DBP] between the increase of activity coefficient of methyl acetate and ionic liquids. The relationship between the decrease of methanol activity coefficient and the ionic liquid is opposite to that mentioned above. The data of methyl acetate-methanol-ionic liquid in the ternary system under isobaric pressure are measured experimentally, and the results can be obtained. When the molar concentration of methyl acetate and methanol was 0.05, the co-boiling point of methyl acetate and methanol disappeared completely. The relative volatilities of methyl acetate in the whole concentration range of the system are calculated to be more than 1. The ability of ionic liquid to separate methyl acetate from methanol azeotropic system is [MMIM] [DMP] [EMIM] [DEP] [BMIM] [DBP]. The maximum relative deviation is obtained from the correlation between e-NRTL model and experimental calculation. The results obtained are 4.483 and 4.801.Compared with the results obtained from the direct calculation of experiments, it is proved that the e-NRTL thermodynamic model can obtain ideal results. All three ionic liquids can be applied to the separation of azeotropic methyl acetate and methanol.
【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】：TQ028

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