甲酸-水-甲酸丁酯体系的等压汽液相平衡研究

用改进的Rose釜测定了101.33 kPa下甲酸-水、甲酸-甲酸丁酯、甲酸-水-甲酸丁酯(互溶区内)的等压汽液相平衡数据。考虑了甲酸在汽相中的缔合效应和非理想性,用Hayden-O’connell关联式修正了汽相的非理想性,用NRTL模型对甲酸-水和甲酸-甲酸丁酯体系的汽液平衡数据进行了关联,得到了相应的模型参数。利用得到的二元体系模型参数,结合部分三元体系汽液平衡数据,关联得到水-甲酸丁酯体系的模型参数。由关联得到的3对二元NRTL模型参数预测三元体系汽液平衡数据,温度平均偏差为1.20℃,甲酸的汽相平均偏差为0.0152,甲酸丁酯的汽相平均偏差为0.0184,实验值与预测值基本吻合。

Study on isobaric vapor-liquid equilibrium of formic acid-water-n-butyl formate systems

Isobaric vapor-liquid equilibrium(VLE) data of the systems of formic acid-water,formic acid-butyl formate and formic acid-water-butyl formate were measured at 101.33 kPa by using an improved Rose equilibria cell.The association and nonideality of formic acid in vapor phase were considered.The nonideality of vapor phase was correlated by Hayden-O'connell equations.VLE data of the systems of formic acid-water and formic acid-butyl formate were correlated by the NRTL model,and the binary interaction parameters were gotten by applying the nonlinear least square method.Combining the obtained model parameters of binary systems with the ternary VLE data,the model parameters of water-butyl formate system were correlated.The model parameters obtained were used to predict ternary VLE data.For ternary system,the average absolute deviations in vapor-phase mole fraction of formic acid and butyl formate were 0.015 2 and 0.018 4 respectively and that in the equilibrium temperature was 1.20 ℃,the experimental value basically agrees with the predicted value.