含醇二元体系热力学性质的研究 Ⅰ.C1至 C5正链醇+苯体系的过量焓

STUDIES ON THERMODYNAMIC PROPERTIES OF BINARY SYSTEMS CONTAINING ALCOHOLS.——Ⅰ.EXCESS ENTHALPIES OF C1 TO C5 NORMAL ALCOHOLS+BENZENE

使用 Picker 流动微量量热器系统测量了298.15K 和常压下甲醇+,乙醇+,正丙醇+,正丁醇+和正戊醇+苯体系的摩尔过量焓。所得结果,一般较间歇式量热器的测量数据稍高。这些体系的最大过量焓在~x 醇=0.30~0.33.正链醇+苯体系的摩尔过量焓的数值,在 C~C之间,随着醇分子中碳原子的数目增多而升高,但两相邻醇 H~E 的差值,则随碳链的增长而逐,渐减小。

The binary systems composed of alcohols and other organic solvents,both in theory and in practice,are important to us.Researches for the thermodynamic properties of these systems can not only provide reliable data and empirical rules for science and technology,but also help to investigate the states,structures of the solutes and sol- vent in solution as well as their interactions.In this series,by measuring the excess thermodynamic functions (such as the heats of mixing,volume changes on mixing and excess free energies) for the systems of Cto Calcohls with various organic solvents we will explore the influence of the size and structure of the molecules present in mixtures on excess thermodynamic functions,and further discuss these effects from theories of solution. In the first part,molar excess enthalpies of methanol+,ethanol+,n-propanol+, n-butanol+and n-amyl alcohol+benzene at 298.15K and under normal pressure have been measured with a Picker flow microcalorimeter.The results obtained was slightly higher than those of the available literature data.Maximum values of Hfor these systems are situated on 0.30-0.33 mole fraction of alcohols.Molar excess enthalpies of the titled systems increase with chain length of the alcohols,whereas the difference between two neighbouring alcohols decrease with increasing of the number of carbon atoms in alcohol.