The Zone Melting and Solid-Liquid Equilibrium of the 2,2'-Bipyridyl-- Biphenyl Eutectic System

Hidemoto NOJIMA

Department of Industrial Chemistry, School of Science and Technology, Meiji University; 1-1-1 Higashimita, Tama-ku, Kawasaki-shi 214-8571 Japan

Solid solubilities in the 2,2'-bipyridyl--biphenyl eutectic system at the eutectic temperature, which correspond to the maximum solubilities, were determined by means of DSC, zone melting and thermal microscopic methods. In this system the relationship between eutectic enthalpy of fusion determined by DSC and composition led to the following straight lines:
where x2 is the mole fraction of 2,2'-bipyridyl; ΔH1e and ΔH2e are the eutectic enthalpies of fusion on the 2,2'-bipyridyl and biphenyl sides from the eutectic composition, respectively. Putting ΔH1e=0 and ΔH2e=0 in the above equations, the maximum solid solubilities were found to be x1es=0.0270 and x2es=0.0573 by mole fraction for the 2,2'-bipyridyl and biphenyl sides, respectively. Moreover, eutectic composition was found to be x2e=0.493 by putting ΔH1e=ΔH2e. On the other hand, solidus curve in the biphenyl side was determined from the equilibrium distribution coefficient of 2,2'-bipyridyl in biphenyl derived from zone melting experiment, and also the value of x2es was found to be 0.0705. By the use of a thermal microscope the solid solubilities were found to be x1es=0.0192 and x2es=0.0603, respectively.

Studies of the Zone Melting. Part 9.

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