有机物临界压缩因子Zc 的估算

由Ｔｃ、Ｐｃ、Ｖｃ3个基本临界参数按Ｚｃ=ＰｃＶｃ/(ＲＴｃ) ( 1 )式定义导出的临界压缩因子广泛用于粘度、导热系数等物性的估算 ,是最重要的物理化学参数之一1,2 ] .Ｚｃ 不能直接测定 ,由实测的Ｔｃ、Ｐｃ、Ｖｃ 按上述定义计算所得的Ｚｃ 值为实验值 .由于很多化合物的临界条件非常荷刻以及部分化合物的不稳定性 ,使目前Ｔｃ、Ｐｃ、Ｖｃ 的实测数据仍然缺乏 ,要先进行Ｔｃ、Ｐｃ、Ｖｃ 的估算 ,这样按 ( 1 )式计算的Ｚｃ 值则视为估算值 ,这样的估算方法亦称为间接估算方法 .Ｚｃ 也可直接估算 ,Ｌｙｄｅｒｓｅｎ、Ｅｄｍｉｓｔｅｒ…

ESTIMATION OF CRITICAL COMPRESSIBILITY FATOR OF ORGANIC COMPOUNDS WITH CORELATION EQUATION

A mathematical model for the estimation of critical constant(Z c)of organic compounds has been proposed as follows:Z c=a 0+a 1x 1+a 2x 2+a 3x2 1+a 4x2 2x 1=T K 1 bM K 2A K 3d K 4,x 1=T K 5 bM K 6A K 7d K 8in which, T b: normal boiling point, M: molecular weight, N: atomic number of molecular; and a 0,a 1,a 2,a 3,a 4, K 1,K 2,K 3,K 4,K 5,K 6,K 7,K 8 are parameters which are various with the kinds of organic compounds. The validity of these models has been tested extensively with the experimental data of 190 organic compounds. The calculation A.D.(%) of Z c are 2 63, which is obviously lower than those estimated by Wang's, Joback's and MXXC's methods, respectively.