トリステアリン-トリパルミチン二成分系のX線回折
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概要
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The phase transition of the polymorphic forms in the binary system, tristearin-tripalmitin, has been studied by X-ray diffraction.<BR>(1) The lowest melting form α was obtained by melting and chilling the mixtures, and the next form β and β was obtained by transition form α-form. All three forms in this binary system formed solid solutions of which long spacings varied with composition of the system.<BR>(2) Using the continuously variable specimen-temperature devise, it was observed that α-form in this system transformed into subα-form at -50°C or so and that this phase trasition was reversible.<BR>(3) Using the same devise, X-ray diffraction pattern of β and β-forms at elevated temperature was obtained up to its melting point. It was observed that the specific lattice spacing in β and β-forms changed at elevated temperatures and authors called β and β at near its melting point as β* andβ* respectively. This β* and β*-forms transformed reversibly into β and β near at room temperature.<BR>(4) Using the same devise, it was observed the α-form transformed into β* in the pure glyceride by heating. In the solid solution, it was concluded that α-form transformed into β* (or β), deformed β*, and β* successively. It was suggested that the deformed β* might be imperfectly β* in which the specific crystal face of β* yet developed. It would be concluded that the intermediate pattern named by Hoerr was attributed to mixture of β* and deformed β*.<BR>(5) The value of side spacings of each polymorphic form is summarized as follows :<BR>(1) β 4.58, 3.85, 3.69Å (room temp.)<BR>β* 4.58, 3.85, 3.75Å (near its mp)<BR>It is observed that the last lattice spacing often changed a little in the solid solutions.<BR>(2) deformed β* 4.58, broad 3.8 Å (near its mp)<BR>(2) β 4.19, 3.80Å (room temp.)<BR>β* 4.19, 3.85Å (near its mp)<BR>(4) α 4.14 Å (room temp.)<BR>sub α 4.12, broad 3.7 Å (below -50°C)
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