Dynamic Molecular Behavior of Semi-Fluorinated Oleic, Elaidic and Stearic Acids in the Liquid State

Yamamoto, Shun; Matsuda, Hirokazu; Kasahara, Yuji; Iwahashi, Makio; Takagi, Toshiyuki; Baba, Teruhiko; Kanamori, Toshiyuki

doi:10.5650/jos.61.649

Cited by 9 publications

(10 citation statements)

References 30 publications

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“…ΔE app of OA is in fair agreement with the value reported by Yamamoto et al . [ 25 ] for the same molecule, and interestingly also with the value reported for liquid TGs [ 36 ]. These results suggest that OA molecular movement within its bulk liquid is considerably reduced compared with MO, and requires an equivalent amount of energy as a TG to initiate diffusion.…”

Section: Resultssupporting

confidence: 71%

“…The group of Iwahashi has thoroughly studied the self-organization of FAs in the neat liquid state [ 17 , 19 - 25 ]. They concluded, using near-infrared spectroscopy and vapor pressure osmosis on various FAs, that these exist mostly as dimers, even at high temperature, where the dimers are the units in their intra- or intermolecular movements.…”

Section: Introductionmentioning

confidence: 99%

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Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

Berman

Meiri

Colnago

et al. 2015

Biotechnol Biofuels

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Background1H low field nuclear magnetic resonance (LF-NMR) relaxometry has been suggested as a tool to distinguish between different molecular ensembles in complex systems with differential segmental or whole molecular motion and/or different morphologies. In biodiesel applications the molecular structure versus liquid-phase packing morphologies of fatty acid methyl esters (FAMEs) influences physico-chemical characteristics of the fuel, including flow properties, operability during cold weather, blending, and more. Still, their liquid morphological structures have scarcely been studied. It was therefore the objective of this work to explore the potential of this technology for characterizing the molecular organization of FAMEs in the liquid phase. This was accomplished by using a combination of supporting advanced technologies.ResultsWe show that pure oleic acid (OA) and methyl oleate (MO) standards exhibited both similarities and differences in the 1H LF-NMR relaxation times (T2s) and peak areas, for a range of temperatures. Based on X-ray measurements, both molecules were found to possess a liquid crystal-like order, although a larger fluidity was found for MO, because as the temperature is increased, MO molecules separate both longitudinally and transversely from one another. In addition, both molecules exhibited a preferred direction of diffusion based on the apparent hydrodynamic radius. The close molecular packing arrangement and interactions were found to affect the translational and segmental motions of the molecules, as a result of dimerization of the head group in OA as opposed to weaker polar interactions in MO.ConclusionsA comprehensive model for the liquid crystal-like arrangement of FAMEs in the liquid phase is suggested. The differences in translational and segmental motions of the molecules were rationalized by the differences in the 1H LF-NMR T2 distributions of OA and MO, which was further supported by 13C high field (HF)-NMR spectra and 1H HF-NMR relaxation. The proposed assignment allows for material characterization based on parameters that contribute to properties in applications such as biodiesel fuels.

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Section: Resultssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

Berman

Meiri

Colnago

et al. 2015

Biotechnol Biofuels

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“…To characterize antioxidant efficacy by 1 H LF‐NMR, it is important to understand the mechanism of oxidation and the chemical morphological characterization of the oils at different stages of oxidation. In our previous paper on the autoxidation of different fatty acid oils, we described in detail the correlation between the molecular structure of linseed oil and its liquid phase morphological chemical domains characterized by 1 H LF‐NMR Linseed oil is primarily PUFA linolenic acid (53.21%), oleic acid (18.51%), and linoleic acid (17.25%), that are self‐associated as hydrogen‐bonded dimers in their liquid phase, that further aggregate to form clusters possessing the structure of a quasi‐smectic liquid crystal, of an interdigitated alternating head to tail arrangement . The clusters aggregate formation is responsible for the fatty acid liquid properties, such as fluidity and viscosity …”

Section: Resultsmentioning

confidence: 99%

¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Resende

Linder

Wiesman

2019

Euro J Lipid Sci & Tech

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A major stability issue of food and other products containing lipids is their susceptibility to oxidation and the efficacy of endogenous or exogenous antioxidants that are sensitive to internal morphological and chemical structures which are difficult to characterize with current analytical methods. This work develops signal reconstruction of 1H LF‐NMR spin‐lattice (T1) and spin‐spin (T2) energy relaxation times into 2D T2 versus T1 peak graphs of the internal chemical and morphological arrangements within lipid materials, with the potential for efficient structural studies of lipid oxidation and antioxidant efficacy in complex foods. This novel NMR inverse Laplace transformation (ILT) signal processing reconstruction is now applied in a PUFA‐rich linseed oil's thermal autoxidation and antioxidant efficacy study. To characterize antioxidant efficacy, it is important to understand the mechanism of oxidation and the chemical and morphological structural aspects. The initial steps of oxidation show a clear peak shift to shorter T2 versus T1 peak values, for the different poly‐unsaturated fatty acids (PUFA), which for mono‐unsaturated and saturated FAs remain unchanged. These peak shifts are within an oxidation time period needed for hydroperoxides formation. For longer oxidation times a new set of T2 versus T1 peaks are generated with shorter T2 and stable and/or increased T1 values, suggesting formation of aldehydes and polymerized oxidation end products. The chemical changes of the fatty acids of linseed oil are confirmed by their gas chromatography analysis during the studied time interval. Similarly peroxides and aldehydes formation trends are confirmed by PV and p‐ansidine tests, respectively for the same time points. Based on the oxidation study the control of T1 and T2 relaxation times by α tocopherol antioxidant is characterized. In effect α tocopherol antioxidant maintains peak stability during linseed oil's thermal autoxidation, in a 2D T2 versus T1 relaxation time graph of peaks assigned to chemical morphological structures, demonstrating α tocopherol's ability to minimize linseed oil's oxidation. Practical Application: Monitoring of food products oxidation and quality control. 1H LF‐NMR T1 and T2 energy relaxation times reconstructed with PDCO into 2D spectra of material analysis has proven to be an advantageous tool to monitor complex chemical and morphological structural changes during the autoxidation of PUFA‐rich linseed oil. It is suggested that an initial oxidation phase generates a shift, of the original linseed peaks along the T1 = T2 diagonal due to hydroperoxide formation. At longer oxidation times there is an accumulation of peaks below the diagonal line assigned to oligomeric/polymeric termination products, generating a significant “bending effect.” α tocopherol addition at effective concentrations is able to change this pattern of PUFA‐rich linseed oil oxidation by blocking early peaks shift and late bending effect.

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“…CAS-numbers, molar masses, melting and boiling points, and critical properties of the compiled substances are also listed in the Supporting Information. They were taken mainly from the handbook of Yaws, but also from the Web site of the Chemical Abstracts Service and other specific references. − …”

Section: Introductionmentioning

confidence: 99%

Self-Diffusion in Molecular Fluids and Noble Gases: Available Data

et al. 2015

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Experimental self-diffusivities of gases, vapors, and liquids obtained by means of tracer techniques and nuclear magnetic resonance are reviewed. The considered substances range from noble gases and simple diatomics (nitrogen, oxygen, carbon monoxide, etc.) to complex organic molecules, such as phenolphthalein dimethyl ether and 2-(α-methylbenzylamino)-5-nitropyridine, although polymers have not been included. Some comments on the applicability of neutron scattering to the determination of self-diffusion coefficients are also made. All the experimental results of the investigated systems are given as Supporting Information, whereas the references, temperatures, and pressures of these data and the main features of the measurement methods are compiled and classified.

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Dynamic Molecular Behavior of Semi-Fluorinated Oleic, Elaidic and Stearic Acids in the Liquid State

Cited by 9 publications

References 30 publications

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Self-Diffusion in Molecular Fluids and Noble Gases: Available Data

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Dynamic Molecular Behavior of Semi-Fluorinated Oleic, Elaidic and Stearic Acids in the Liquid State

Cited by 9 publications

References 30 publications

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

Study of liquid-phase molecular packing interactions and morphology of fatty acid methyl esters (biodiesel)

1H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants

Self-Diffusion in Molecular Fluids and Noble Gases: Available Data

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¹H LF‐NMR Energy Relaxation Time Characterization of the Chemical and Morphological Structure of PUFA‐Rich Linseed Oil During Oxidation With and Without Antioxidants