The use of spin-echo bessel analysis and rotating-frame relaxation techniques to measure self-diffusion over an extended viscosity range

Walker, N. A.; Lamb, D.M; Jonáš, J.; Dare-Edwards, M. P.

doi:10.1016/0022-2364(87)90280-0

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…Some authors distinguish reproducibility from reliability, and then, we have placed the last parameter in italics in brackets. Numerically published alkanes of Bachl, methane of Oosting and Trappeniers, 2-ethylhexylbenzoate of Walker et al, and ketones and acetates of Petrowsky et al are published in figures elsewhere, − so we have only taken into account the numbers and have not added the graphical references to Table nor to the Supporting Information.…”

Section: Methodsmentioning

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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Section: Methodsmentioning

confidence: 99%

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

et al. 2015

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“…Consequently, it seems useful to have good high-pressure viscosity data for pure viscous substances that might be considered as alternatives to DIDP and the commercial mixtures. Here data are reported for two esters having the advantage of being available as pure isomers, 2-ethylhexyl benzoate (EHB) and bis(2-ethylhexyl) phthalate (DEHP), as shown by the 13 C NMR studies of Jonas and co-workers, − and for 2,6,10,15,19,23-hexamethyltetracosane or squalane, a hydrocarbon of similar viscosity. Like EHB and DEHP, , squalane has been used in viscoelasticity and elastohydrodynamics studies of lubricants. − All three substances are also of more fundamental interest in terms of liquid-state theories as glass-formers with extended experimentally accessible viscosity ranges. − …”

Section: Introductionmentioning

confidence: 99%

Temperature and Pressure Dependence of the Viscosities of 2-Ethylhexyl Benzoate, Bis(2-ethylhexyl) Phthalate, 2,6,10,15,19,23-Hexamethyltetracosane (Squalane), and Diisodecyl Phthalate

Harris

2009

J. Chem. Eng. Data

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The viscosities of the esters 2-ethylhexyl benzoate (EHB), bis(2-ethylhexyl) phthalate (DEHP), and the long-chain hydrocarbon 2,6,10,15,19,23-hexamethyltetracosane (squalane, C 30 H 62 ) have been measured between (0 and 80) °C with a falling-body viscometer to a maximum pressures of (315, 371, and 379) MPa, respectively. The expanded uncertainty is estimated at ( 2 %. These substances are possible alternatives to diisodecyl phthalate (DIDP) as reference materials for viscometry at moderate to high pressures. In addition, further measurements for DIDP are reported in the range (0.1 to 90) MPa and (25 to 75) °C to supplement those given by Harris and Bair (

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“…Our continuing efforts of studying molecular dynamics of complex, viscous liquids were motivated by the need for improved understanding of the functional fluids at the molecular level . In previous studies, the fluid and molecular properties of 2-ethylhexyl benzoate (EHB) have been investigated as a function of temperature and pressure using several experimental techniques. − Comprising both rigid phenyl ring and flexible alkyl chain, EHB has represented a model compound for hydrocarbon-based elastohydrodynamic lubricants . The studies of the molecular dynamics of EHB at various experimental conditions have provided important information on the motion of this model lubricant molecule.…”

Section: Introductionmentioning

confidence: 99%

Carbon-13 NMR Study of the Effect of Confinement on the Molecular Dynamics of 2-Ethylhexyl Benzoate

Sullivan

Kim

et al. 1999

Langmuir

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Spin-lattice relaxation times of individual carbons in 2-ethylhexyl benzoate (EHB) in bulk and confined to porous silica glasses of pore radii of 33, 52, and 102 Å were measured as a function of temperature from +40 to -51 °C. The two-state fast exchange model was successfully applied, in the wide temperature range including beyond the motional narrowing regime, to determine the spin-lattice relaxation times of the molecules in the surface layer (T1S) as a function of temperature. The Cole-Davidson distribution model was used to analyze the relaxation data for both the bulk (T1B) and surface layer (T1S) of the confined liquid. The line broadening of confined EHB at lower temperatures below -21 °C inherently limited the temperature range over which T1S could be estimated and prevented the quantitative analysis of T1S by the model. Through the phenomenological comparison of T1S with T1B in terms of the parameters of the Cole-Davidson model, it was found that the motional behavior of the phenyl ring part of the EHB molecule was significantly affected by the surface interaction and the effect is smaller for the flexible alkyl chain. Small temperature dependence of the relaxation rate of T1S at motional narrowing regime showed a characteristic feature of liquid diffusing on a two-dimensional surface. In addition, the results of the quantitative analysis of T1B were compared with a previous experiment performed as a function of pressure.

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The use of spin-echo bessel analysis and rotating-frame relaxation techniques to measure self-diffusion over an extended viscosity range

Cited by 4 publications

References 9 publications

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

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

Temperature and Pressure Dependence of the Viscosities of 2-Ethylhexyl Benzoate, Bis(2-ethylhexyl) Phthalate, 2,6,10,15,19,23-Hexamethyltetracosane (Squalane), and Diisodecyl Phthalate

Carbon-13 NMR Study of the Effect of Confinement on the Molecular Dynamics of 2-Ethylhexyl Benzoate

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