甲胺与水多元系常压汽液平衡研究

Study on the Isobaric Vapor-Liquid Equilibrium for Methylamines and H_2O Multicomponent Systems

用新型泵式沸点仪测定了常压下一甲胺-二甲胺-三甲胺-水四元系在不同液相组成时的沸点;由所测的甲胺-水二元系数据,用过量自由焓Q函数间接法推算了与之平衡的汽相组成,再用最小二乘法求出甲胺与水间二元体系的液相活度系数模型参数;甲胺与甲胺间二元体系的液相活度系数模型参数则通过拟合它们与水构成的三元系获取;由所得的最佳二元系参数用于该体系四元系汽液相平衡数据的预测,将计算的泡点与实验测得的沸点作了比较,结果表明两者吻合良好。

Experimental vapor-liquid equilibrium (VLB) data for a quaternary system of monomethylamine-dimethylamine-trimethylamine-H2O and constituent binary and ternary systems were measured at 101.325 kPa by using a new type of magnetic pump-ebulliometer. Based on the experimental data of the methylamine-H2O binary systems, the equilibrium compositions of the vapor phase of the methylamine-H2O binary systems were calculated from the Q function of molar excess Gibbs energy by the indirect method, and then the model parameters of liquid activity coefficient were correlated by the least-squares fit. The model parameters of the monomethylamine-dimethylamine, monomethylamine-trimethylamine and dimethylamine-trimethylamine binary systems were determined by the non-linear regression of the correspondence ternary systems formed by the correspondence binary methylamines with H2O. The prediction of vapor-liquid equilibrium data of quaternary system was based on the acquired optimum model parameters from the binary systems. In comparison with the experimental boiling points, the calculated bubbling point temperatures were in good agreement with the experimental ones.