Thermophysical properties of liquid squalane C30H62 within the temperature range of 298.15–413.15 k at atmospheric pressure

Korotkovskii, Vadim I.; Lebedev, A. V.; Ryshkova, Olga S.; Bolotnikov, Mikhail F.; Shevchenko, Yu. E.; Neruchev, Yu. A.

doi:10.1134/s0018151x12040116

Cited by 12 publications

(7 citation statements)

References 19 publications

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“…The squalane molecules and HOPG system were described by an all-atom OPLS (optimized potentials for liquid simulations) force field (59). The squalane molecules without any confinement in the HOPG box were found to have a density of 803 kg/m 3 at 298.15 K, in agreement with the experimental value of 804 kg/m 3 (60). The system was an isothermal-isobaric (NpT) ensemble maintained at 298 K and 1 bar using a velocity-rescale thermostat (61) and Parrinello-Rahman barostat (62,63) with coupling times of 0.5 and 5 ps, respectively.…”

Section: Simulationssupporting

confidence: 70%

Lubricated friction around nanodefects

2020

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The lubrication properties of nanoconfined liquids underpin countless natural and industrial processes. However, our current understanding of lubricated friction is still limited, especially for nonideal interfaces exhibiting nanoscale chemical and topographical defects. Here, we use atomic force microscopy to explore the equilibrium and dynamical behavior of a model lubricant, squalane, confined between a diamond tip and graphite in the vicinity of an atomic step. We combine high-resolution imaging of the interface with highly localized shear measurements at different velocities and temperatures to derive a quantitative picture of the lubricated friction around surface defects. We show that defects tend to promote local molecular order and increase friction forces by reducing the number of stable molecular configurations in their immediate vicinity. The effect is general, can propagate over hundreds of nanometers, and can be quantitatively described by a semiempirical model that bridges the molecular details and mesoscale observations.

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Section: Simulationssupporting

confidence: 70%

Lubricated friction around nanodefects

2020

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“…Beyond these compilations a large number of recent papers presenting the heat-capacity data of several classes of compounds and of individual molecules of any kind as well as their temperature dependence have been published up to the present. Special mention shall be given to the hydrocarbons [49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65], halogenated hydrocarbons [66,67,68,69,70,71], unsubstituted and substituted alcohols and polyols including sugar derivatives [72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107], phenol derivatives [108,109], carboxylic acids […”

Section: Resultsmentioning

confidence: 99%

Calculation of the Isobaric Heat Capacities of the Liquid and Solid Phase of Organic Compounds at and around 298.15 K Based on Their “True” Molecular Volume

Naef

2019

Molecules

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A universally applicable method for the prediction of the isobaric heat capacities of the liquid and solid phase of molecules at 298.15 K is presented, derived from their “true” volume. The molecules’ “true” volume in A3 is calculated on the basis of their geometry-optimized structure and the Van-der-Waals radii of their constituting atoms by means of a fast numerical algorithm. Good linear correlations of the “true” volume of a large number of compounds encompassing all classes and sizes with their experimental liquid and solid heat capacities over a large range have been found, although noticeably distorted by intermolecular hydrogen-bond effects. To account for these effects, the total amount of 1303 compounds with known experimental liquid heat capacities has been subdivided into three subsets consisting of 1102 hydroxy-group-free compounds, 164 monoalcohols/monoacids, and 36 polyalcohols/polyacids. The standard deviations for Cp(liq,298) were 20.7 J/mol/K for the OH-free compunds, 22.91 J/mol/K for the monoalcohols/monoacids and 16.03 J/mol/K for the polyols/polyacids. Analogously, 797 compounds with known solid heat capacities have been separated into a subset of 555 OH-free compounds, 123 monoalcohols/monoacids and 119 polyols/polyacids. The standard deviations for Cp(sol,298) were calculated to 23.14 J/mol/K for the first, 21.62 J/mol/K for the second, and 19.75 J/mol/K for the last subset. A discussion of structural and intermolecular effects influencing the heat capacities as well as of some special classes, in particular hydrocarbons, ionic liquids, siloxanes and metallocenes, has been given. In addition, the present method has successfully been extended to enable the prediction of the temperature dependence of the solid and liquid heat capacities in the range between 250 and 350 K.

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“…Among the available correlations, the most sure is the expression (8) based on the Trouton-HildebrandEverett rule and the proposed correlation with the acentric factor (9). Although other studied correlations can give a better accuracy for some studied substances, the T-H-E-based approach is most stable and, on average, gives results comparable with the overall DIPPR database errors of estimation.…”

Section: Resultsmentioning

confidence: 53%

“…7 represents the data with respect to this variable. The experimental data for n-hexane, noctane, n-dodecane, n-hexadecane, and n-tetracosane are taken from (Neruchev et al, 2005), and those for n-squalane are taken from (Korotkovskii et al, 2012). …”

Section: Resultsmentioning

confidence: 99%

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Can DIPPR Database be Used for an Estimation of the Speed of Sound? A Case Study of Liquid Hydrocarbons

Postnikov

2016

Archives of Acoustics

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The paper analyses a possibility of utilising the information which is contained in DIPPR database for a calculation of the speed of sound, which is absent there. As an example, liquid hydrocarbons are considered: n-hexane, 1-hexene, cyclohexane, cyclohexene, benzene, and 1-hexanols, as well as representatives of n-alkanes with various hydrocarbon chain lengths. It is shown that the Brelvi-O'Connell correlation for the reduced bulk modulus, supplied with the correlations for the internal pressure at the normal boiling temperature, results in the values having accuracy comparable with other DIPPR data for the region below the boiling point bounded by the values of the reduced density around ρr ≈ 3.5. The source of errors originated from the Brelvi-O'Connell correlation for larger reduced densities is discussed.

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Thermophysical properties of liquid squalane C30H62 within the temperature range of 298.15–413.15 k at atmospheric pressure

Cited by 12 publications

References 19 publications

Lubricated friction around nanodefects

Lubricated friction around nanodefects

Calculation of the Isobaric Heat Capacities of the Liquid and Solid Phase of Organic Compounds at and around 298.15 K Based on Their “True” Molecular Volume

Can DIPPR Database be Used for an Estimation of the Speed of Sound? A Case Study of Liquid Hydrocarbons

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