Structure and polymorphic transformations in elaidic acid (trans-ω9-octadecenoic acid)

✍ Scribed by Satoru Ueno; Toshiyuki Suetake; Junko Yano; Masao Suzuki; Kiyotaka Sato

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 491 KB
• Volume: 72
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(94)90014-0

✦ Synopsis

A study of polymorphic transformations in elaidic acid (trans-~9-octadecenoic acid) was performed with differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy and optical microscopy. One polymorph was isolated whose melting temperature was 44.5°C, and enthalpy of fusion was 53.6 k J/tool. The subcell of elaidic acid was O~, and long spacing was 4.91 rim. The binary mixtures of elaidic acid/stcaric acid (octadecanoic acid) (EA/SA) and elaidic acid/oleic acid (cis~9-octadecenoic acid) (EA/OA) exhibited eutectic nature, eutectic points being EA/SA = 92/8 and EA/OA = 15/85. These results show that elaidic acid is not miscible with stearic and oleic acid isomers. However, the effects of mixing elaidic and stearic acids on the 7-~ transformation of oleic acid crystal fractions indicate that elaidic acid molecules are incorporated in the oleic acid crystal lattices as impurities more easily than stearic acid molecules.