摘要
用气液色谱法测量了不同温度下C_1—C_4醇类的各异构物在二苯甲烷、联苄、二苯乙炔、二苯甲酮及二苯亚砜中的无限稀活度系数γ_1、偏摩尔过量焓_1~K及偏摩尔过量熵_1~E。用Kretschmer-Wiebe模型计算各醇类在二苯甲烷、联苄、二苯乙炔中的自身缔合常数K_A,得到在同一溶剂中,C_1—C_4醇类,K_A减小次序。用同一模型计算各醇类在二苯甲酮、二苯亚砜中的交叉缔合常数K_(AB),得到在同一溶剂中,K_(AB)减小次序。
The infinite dilution activity coefficients γ_1, partial molar excess enthalpies (?) and entropies (?) of C_1—C_4 alcohols in inert solvents diphenyl-methane, dibenzyl and diphenylacetylene along with active solvents benzophenone and diphenylsulfoxide have been measured.
The values of γ_1 in inert solvent decrease in the order:
methanol>ethanol>n-propanol>n-butanol;
n-propanol>isopropanol;
n-butanol～isobutanol>tert-butanol>sec-butanol.but no regular order has been found in active solvent.
The activity coefficients have been treated by Kretschmer-Wiebe association model combining with a Hildebrand-Scatchard term. The self association constants K_A of alcohols in inert solvent decrease in the order:
methanol>ethanol>n-propanol>n-butanol;
n-propanol>isopropanol;
n-butanol>tert-butanol>isobutanol～sec-butanol.
At the same temperature, the values of K_A of each alcohol in the studied inert solvents are nearly equal. It can be safely assumed that each alcohol in the solvents which have two benzene rings are all having a common value K_A. In addition, using the average K_A in studied inert solvents, the cross association constant K_(AB) of alcohol with active solvent has been evaluated.
The values of K_(AB) deerease in the order:
methanol>ethanol>n-propanol>-butanol;
n-propanol>isopropanol;
n-butanol>isobutanol>sec-butanol>tert-butanol.
It has been found that the associated ability of alcohol with diphenylsulfoxide is greater than with benzophenone.
On condition that the factor K_(AB) is comparable with K_A, the value of γ1 would be close to unity. And the irregular phenomenon of γ1 in active solvent can be given a satisfactory explanation.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1992年第1期5-10,共6页
Acta Chimica Sinica
基金
国家自然科学基金
