直鎖長鎖第一臭化物の相転移 (第4報) : 1-ブロモオクタデカンの熱的, 誘電的研究

概要

論文の詳細を見る
A differential scanning calorimeter (Perkin Elmer DSC-1B) has been applied to the thermal investigation for phase change phenomenon of 1-bromooctadecane, and different behavior in the transition of this bromide has been observed at different thermal treatments. The phase transition phenomenon was found at cooling process. The transition temperature, 19°C, was consistent with that expected from the result of previous studies in a series of normal higher primary bromides containing 22, 24, 26 and 28 carbon atoms. The value of transition entropy is close to those of 1-bromodocosane and 1-bromotetracosane. This transition behavior could be explained by the example of these compounds. The phase transition of this bromide can be regarded as rotational one. The behavior of these DSC curves is explained by the aid of free energy-temperature schematic diagram. The metastable low temperature phase which first appeared below the transition point at cooling changed into stable one, irreversibly. The sample of this stable state, as well as the recrystallized sample, revealed no phase transition phenomenon in heating process. In cooling process, a exothermic peak have been observed when the sample is held at a constant temperature on high temperature phase. The energy calculated from this peak was nearly equal to the latent heat of phase transition of this bromide. The high temperature phase is considered to be metastable one and changes to stable phase spontaneously. Dielectric constant measurements were carried out using a transformer bridge at 10kHz. No phase transition phenomenon was observed both in cooling and heating processes. There was the discrepancy between the results of DSC measurement and that of dielectric constant one, This is possibly due to the metastable state of high temperature phase and the difference of precision in temperature control for both measurements.
社団法人日本油化学会の論文

直鎖長鎖第一臭化物の相転移 (第4報) : 1-ブロモオクタデカンの熱的, 誘電的研究

スポンサーリンク

概要

著者

関連論文

スポンサーリンク