DSC法测定联苯乙醇/异丙醇/正丙醇二元溶液的比定压热容

Determining the Heat Capacity at Constant Pressure of Biphenyl+Ethanol/2-propylalcohol /1-propylalcohol Solutions with DSC Method

利用差示扫描量热仪(DSC)测定了联苯+乙醇/异丙醇/正丙醇二元体系在不同温度不同组成下的比定压热容(cp).并将联苯+乙醇/异丙醇/正丙醇二元体系的cp与联苯质量分数和温度进行了多项式关联,推导出各体系计算cp的方程.实验结果表明:联苯+乙醇/异丙醇/正丙醇溶液的cp随温度的升高而增大,随联苯质量分数的增加而减小;对比关联cp方程的计算值与实验值可知:3种二元溶液联苯+乙醇/正丙醇/异丙醇的cp平均相对误差分别为0.187%,、0.386%,、0.222%,,表明这些方程可用于计算联苯+乙醇/异丙醇/正丙醇溶液在一定温度和组成下的cp,为联苯结晶过程提供所需的基础热力学数据.

The heat capacity at constant pressure of biphenyl ＋ ethanol/2-propylalcohol/1-propylalcohol solutions at different temperature and concentration were determined by DSC. Cp was correlated with Biphenyl content and the temperature （T）by means of polynomial regression analysis, and the equation of binary system was established to calculate Cp. The results showed that the cp of biphenyl ＋ ethanol/2-propylalcohol/1-propylalcohol solutions increased with the increasing temperature and decreased with the increasing biphenyl content. Calculated values were compared with the experimental data. The average relative deviations of Cp for biphenyl ＋ ethanol/1-propylalcohol/2-propylalcohol solutions are 0.187% , 0.386% and 0.222% respectively. With these equations, Cp of biphenyl ＋ ethanol/2-propylalcohol/1-propylalcohol solutions can be calculated under different temperatures and with different biphenyl contents. The research can provide some basic thermodynamics data for the biphenyl crystallization process.