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Polymorphic transformation of 1,3‐distearoyl‐ sn ‐2‐linoleoyl‐glycerol
Author(s) -
Takeuchi M.,
Ueno A.,
Yano J.,
Floter E.,
Sato K.
Publication year - 2000
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-000-0195-1
Subject(s) - crystallography , chain (unit) , transformation (genetics) , diffraction , infrared spectroscopy , hexagonal crystal system , fourier transform infrared spectroscopy , chemistry , materials science , organic chemistry , physics , optics , biochemistry , astronomy , gene
Polymorphic transformation behavior of sub‐α 1 , sub‐α 2 , α, and γ in 1,3‐distearoyl‐ sn ‐2‐linoleoyl‐glycerol (SLS) has been studied with X‐ray diffraction, differential scanning caloremetry, and Fourier‐transform infrared spectroscopy. Synchrotron radiation X‐ray beam was employed to observe rapid transformation processes from the sub‐α and α forms to the γ form. The chain length structures were double in sub‐α 1 , sub‐α 2 , and α, whereas γ was of triple chain‐length structure. The subcell packing was pseudohexagonal for the two sub‐α forms, hexagonal for the α form, and parallel type for the γ form. In comparison with 1,3‐distearoyl‐ sn ‐2‐oleoyl‐glycerol (SOS), the occurrence behavior of sub‐α, α, and γ of SLS was the same as that of SOS. However, the absence of β′ and β was unique for SLS. The chain‐chain interactions between the linoleoyl moieties may stabilize the γ form, prohibiting the transformation into β′ and β forms. The presence of two cis double bonds may cause this stabilization, revealing the disordered chain conformation of the unsaturated chains.