Optically Active and Racemic Glycerides. II. Thermodynamic Studies on the Polymorphic Transition of (<i>R</i>)- and (<i>RS</i>)-1,2-Diglycerides

Iwahashi, Makio; Ashizawa, Kazuhide; Ashizawa, Miyuki; Kaneko, Yoshihide; Muramatsu, Mitsuo

doi:10.1246/bcsj.57.956

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…However, metastable forms of α and β‘ exhibit solid solution phases . Similar results were reported for the mixtures of optically active diacylglycerols . As for the acyl chain composition, no solubility of the monosaturated acid TAG was obtained in a crystal of cis -monounsaturated acid TAG .…”

Section: Introductionsupporting

confidence: 76%

“…7 Similar results were reported for the mixtures of optically active diacylglycerols. 8 As for the acyl chain composition, no solubility of the monosaturated acid TAG was obtained in a crystal of cis-monounsaturated acid TAG. 7 An interesting study, however, recently showed that the effect of the trans-configuration of the double bond is to modify the phase behavior through partial solubilization in the mixtures EEE-OOO and EEE-SSS (E, elaidoyl).…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic and Kinetic Study on Phase Behavior of Binary Mixtures of POP and PPO Forming Molecular Compound Systems

et al. 1997

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The phase behavior of PPO (sn-1,2-dipalmitoyl-sn-3-oleoylglycerol) and POP (sn-1,3-dipalmitoyl-sn-2-oleoylglycerol) binary mixture was examined using differential scanning calorimetry, conventional and synchrotron radiation X-ray diffraction (XRD), and highly pure samples. A molecular compound, βC, was formed at the 1:1 concentration ratio of PPO and POP, giving rise to two monotectic phases of PPO/compound and compound/POP in a juxtapositional way. βC has a long spacing value of 4.1 nm of double chain length structure. In the PPO/compound region, the DSC melting peak increased with increasing PPO concentration, whereas the DSC melting peak increased with increasing POP concentration in the compound/POP region. The melting point of βC was lowest at 31.2 °C. Time-resolved XRD study unveiled the formation of molecular compounds in metastable forms, αC and β‘C, having the same PPO/POP concentration ratio as βC. αC and β‘C exhibited monotectic phases with corresponding metastable forms of the pure components. In αC, two hexagonal packing XRD short spacing peaks were obtained for αC, corresponding to a differently packed hexagonal subcell of two leaflets. A structure model of the PPO/POP molecular compound is proposed, involving separation of palmitoyl chain leaflet and palmitoyl−oleoyl mixed-acid chain leaflet in the double chain length structure. This model justifies the structure of βC of SOS/SSO proposed by Engstrom (Engstrom, L. J. Fat Sci. Technol. 1992 94, 173−181), in which the saturated and unsaturated chains are packed in the same leaflet of the double chain length. The present work additionally proved that the formation of the molecular compound was present in the αC and β‘C metastable forms, as directly proved by dynamic X-ray diffraction study using synchrotron radiation.

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Section: Introductionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Thermodynamic and Kinetic Study on Phase Behavior of Binary Mixtures of POP and PPO Forming Molecular Compound Systems

et al. 1997

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“…However, metastable forms of a and ft exhibit solid solution phases.11 Similar results were reported for the mixtures of optically active diacylglycerols. 18 As to the acyl chain composition, no solubility of the monosaturated acid TAG was obtained in a crystal of cis-monounsaturated acid TAG.11 An interesting study, however, reported recently that the effect of the trans configuration of a double bond is to modify the phase behavior through partial solubilization in the mixtures EBE-OOO and EEE-SSS (Eelaidoyl).19…”

Section: Discussionmentioning

confidence: 99%

Phase behavior of mixed systems of SOS and OSO

Koyano¹,

Hachiya²,

Sato³

1992

J. Phys. Chem.

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Iyoda, T.; Ohtani, A,; Shimidzu, T.; Honda, K. Chem. L r r . 1986,687. (c) Yoneyama, H.; Hirai, T.; Kuwabata, S.; Ikcda, 0. Chem. Leu. 1986,1243. (d) Shimidzu, T.; Ohtani, A.; Iyoda, T.; Honda, K.The phase behavior of mixed systems of SOS (sn-1,3-distearoyl-sn-2-oleoylglycerol) and OS0 (sn-1.3-dioleoyl-sn-2stearoylglycerol) was studied with X-ray diffractometry and thermal analysis by using pure samples (>98.0%). A molecular compound was formed at the mixture of equal weight ratio, giving rise to two monotectic phases of SOS/compound and compound/OSO in a juxtapositional way. The stable form of the compound, &, has an interlamellar distance of 44.72 A of double chain length structure, which is in contrast to the triple chain length structure of the stable forms of SOS and OS0 having the same interlamellar distance of 65 A. &was formed through specific molecular interactions between stearoyl and oleoyl chains connected to glycerol groups: stearoyl chains at the 1,3-positions of SOS and at the 2-pition of OS0 are packed together in one leaflet of the double chain length lamellae, whereas another leaflet contains oleoyl chains of the two molecules. In the monotoctic region of SOS/compound, two crystals are present below the melting point of Be, 36 O C . Above that temperature, the stable crystals of SOS equilibrated with mixed liquid are present. In the monotectic region of compound/OSO, 8, is present with mixed liquid above the melting point of the stable form of OSO, 25 OC, below which two crystal fractions of the compound and OS0 are present. 8, was expected to have a congruent melting point, according to its unique melting and crystallizing behavior. The compound formation having the double chain length structure was also observed in the mixtures of pOP/OSO and POS/OSO, in which P is a palmitoy1 chain. A molecular model of the compound crystal is proposed, based on the molecular structures of SOS, OSO, and principal monounsaturated fatty acids. IaboductionMolecular packings in fats and lipids have important implications for their physical Properties in crystalline, liquid crystalline, and membrane states.' Biologically important fats and lipids are usually composed not only of different chain lengths but of saturated as well as unsaturated chains. These chains are attached to the same backbones, such as glycerol groups, exhibiting close structural proximity. Aliphatic chain-chain interactions in these 0022-3654/92/2096-105 14$03.00/0 fats and lipids are critical in terms of the structurtfunction relationship.2In the case of acylglycerols, the packing conditions are dependent on the chemical natures of fatty acid moieties: chain length, parity (odd or even), unsaturation (cis or trans), etcq2 are remarkably dependent on whether the acyl chains contain cis unsaturation or not. This is due to the fact that the aliphatic Particularly, the moiecular struchves and t h e r " i c behavior

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Section: Stereochemical Perspective On Polymorphism Of Acylglycerolsmentioning

confidence: 99%

Polymorphism of Acylglycerols: A Stereochemical Perspective

Craven

Lencki

2013

Chem. Rev.

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Optically Active and Racemic Glycerides. II. Thermodynamic Studies on the Polymorphic Transition of (R)- and (RS)-1,2-Diglycerides

Cited by 11 publications

References 8 publications

Thermodynamic and Kinetic Study on Phase Behavior of Binary Mixtures of POP and PPO Forming Molecular Compound Systems

Thermodynamic and Kinetic Study on Phase Behavior of Binary Mixtures of POP and PPO Forming Molecular Compound Systems

Phase behavior of mixed systems of SOS and OSO

Polymorphism of Acylglycerols: A Stereochemical Perspective

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