【作者】 付敏；

【导师】 陈瑶；

【作者基本信息】 暨南大学 ， 应用化学， 2009， 硕士

【摘要】 碳酸二乙酯(DEC)是重要的绿色化学品,近年来发现DEC可以作为汽油的含氧抗爆添加剂,是传统的含氧抗爆添加剂甲基叔丁基醚(MTBE)最具有竞争力的替代品。本文对含DEC的多元组分液液相平衡进行了研究,准确测定了含DEC和碳酸二甲酯(DMC)、MTBE、正庚烷、醇、水的三元和四元混合物的液液相平衡数据,并进一步探讨了数据在判断DEC作为汽油添加剂应用方面的性能。采用气相色谱技术测定了含DEC或MTBE的6个三元体系,5个四元体系的液液相平衡数据,三元体系分别为:水+甲醇+DEC、水+乙醇+DEC、水+DEC+正庚烷、水+MTBE+DEC、水+DMC+DEC、水+MTBE+正庚烷;四元体系分别为:水+乙醇+DEC+正庚烷、水+乙醇+MTBE+DEC、水+MTBE+DEC+正庚烷、水+乙醇+DMC+DEC、水+DMC+DEC+正庚烷。根据实验测定的三元和四元体系液液相平衡数据,分别计算了各个体系中每个组分的分配系数,结合前人做的相关三元体系,分析了DEC对水和汽油体系的影响,结论如下:DEC单独作为汽油添加剂使用时,DEC的添加不会造成正庚烷对水的潜在污染,也不会加深水对汽油体系的影响;当DEC与乙醇混合做为汽油添加剂使用时,能明显降低乙醇和水的互溶性,避免相分离的发生,同时也不会造成正庚烷对水的潜在污染;当DEC与DMC混合做为汽油添加剂使用时,能减小DMC对水环境及水对汽油体系的影响,同时也不会造成正庚烷对水的潜在污染;但是DEC与MTBE混合作为汽油添加剂使用的效果不好,反而会使MTBE对水环境的影响稍稍变大;从水和汽油体系的互溶性来看,DEC比MTBE更适合做汽油添加剂。运用Modified UNIQUAC和Extended UNIQUAC模型对所测体系进行了关联和预测计算,结果表明:与Extended UNIQUAC模型相比,Modified UNIQUAC模型更能精确的关联所测的三元和四元体系,实验数据和关联的结果很吻合。因此,在化工分离设计中,可以应用Modified UNIQUAC模型和相互作用参数的最佳值去推算复杂的多元混合物的液液相平衡数据。更多还原

【Abstract】 Diethyl carbonate(DEC) is one of the important environmentally benign chemicals.In recently,it was founded that DEC could be used as gasoline additive to replace the traditional gasoline additive methyl tert-butyl ether(MTBE) because of its good anti-knocking property.In this paper,multicomponent liquid-liquid equilibria(LLE) properties of DEC were studied,and the LLE data of ternary and quatemary mixtures which containing DEC with dimethyl carbonate (DMC) or MTBE or heptane or alcohol and water was accurately measured,and the corresponding application of the LLE data to assess the performance of DEC in clean gasoline was discussed.Gas chromatograph technique has been applied to determine LLE data for six ternary systems and five quaternary systems composed of DEC or MTBE.The LLE data for the six ternary mixtures of the water + methanol + DEC,water + ethanol + DEC,water + DEC + heptane,water + MTBE + DEC,water + DMC + DEC and the water +MTBE +heptane systems, and the five quaternary mixtures of the water + ethanol + DEC + heptane,water + ethanol + MTBE + DEC,water + MTBE + DEC + heptane,water + ethanol + DMC + DEC and the water + DMC + DEC + heptane systems have been investigated at 298.15 K and atmospheric pressure. Calculating the distribution coefficients for each component based on the LLE data,and analyzing the effect of DEC on water and gasoline compared with the formers studies,the main conclusions are as following: the addition of DEC alone to a water + heptane mixtures leads to no measurable increase in heptane solubility in water;the addition of DEC with ethanol to a water + heptane mixtures leads to an evident decrease in the intersolubility of water and ethanol,and no measurable increase in heptane solubility in water,it can aviod the phenomenon of phase separation;the addition of DEC with DMC to a water + heptane mixtures leads to a decrease in DMC solubility in water and a decrease in water solubility in oil and no measurable increase in heptane solubility in water; but the addition of DEC with MTBE to a water + heptane mixtures leads to a little increase in MTBE solubility in water;DEC could be considered as a suitable alternative gasoline additive to MTBE in the view of the intersolubility of water and gasoline.The experimental ternary and quaternary LLE data have been satisfactorily correlated by using a Modified UNIQUAC model with additional ternary and quaternary interaction parameters.Further,the calculated results obtained from the Modified UNIQUAC model are compared with those obtained from the Extended UNIQUAC model.The correlated results given by the Modified UNIQUAC model are in good agreement with the experiment result for all the systems investigated here.This model and these multibody interaction parameters obtained in this work can be applied to predict LLE properties of complicated fluid mixtures in separation process.更多还原