Density and Viscosity Measurements of 2,2,4-Trimethylpentane (Isooctane) from 198 K to 348 K and up to 100 MPa

Pádua, Agı́lio A. H.; Fareleira, João M. N. A.; Calado, Jorge C. G.; Wakeham, W. A.

doi:10.1021/je950191z

Cited by 111 publications

(62 citation statements)

References 25 publications

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“…The temperature-dependent viscosity coefficients of isooctane have been obtained from the literature. 56 Similar to ANS, the anisotropy of the probe C-500 displays triple-exponential decay with time constants of 0.1 ns (32%), 1.2 ns (42%), and 40.5 ns (26%) ( Table 5). The faster and slower rotational time constants (i.e.τ 1 andτ 2 in Table 5) obtained for the probe C-500 in w 0 ) 10 RM at different temperatures are in good agreement with those reported by Mitra et al 6 in the AOT RM system.…”

Section: Resultsmentioning

confidence: 94%

Validation and Divergence of the Activation Energy Barrier Crossing Transition at the AOT/Lecithin Reverse Micellar Interface

et al. 2008

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In this report, the validity and divergence of the activation energy barrier crossing model for the bound to free type water transition at the interface of the AOT/lecithin mixed reverse micelle (RM) has been investigated for the first time in a wide range of temperatures by time-resolved solvation of fluorophores. Here, picosecondresolved solvation dynamics of two fluorescent probes, ANS (1-anilino-8-naphthalenesulfonic acid, ammonium salt) and Coumarin 500 (C-500), in the mixed RM have been carefully examined at 293, 313, 328, and 343 K. Using the dynamic light scattering (DLS) technique, the size of the mixed RMs at different temperatures was found to have an insignificant change. The solvation process at the reverse micellar interface has been found to be the activation energy barrier crossing type, in which interface-bound type water molecules get converted into free type water molecules. The activation energies, E a , calculated for ANS and C-500 are 7.4 and 3.9 kcal mol -1 , respectively, which are in good agreement with that obtained by molecular dynamics simulation studies. However, deviation from the regular Arrhenius type behavior was observed for ANS around 343 K, which has been attributed to the spatial heterogeneity of the probe environments. Time-resolved fluorescence anisotropy decay of the probes has indicated the existence of the dyes in a range of locations in RM. With the increase in temperature, the overall anisotropy decay becomes faster revealing the lability of the microenvironment at elevated temperatures.

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Section: Resultsmentioning

confidence: 94%

Validation and Divergence of the Activation Energy Barrier Crossing Transition at the AOT/Lecithin Reverse Micellar Interface

et al. 2008

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“…It is hoped that this instrument may contribute to the establishment of a new standard reference fluid for viscosities on the order of 100 mPa‚s. 12 ; e certified reference specimen PTB 100B 11 ; f 2,2,4-trimethylpentane 16 ; and g 2,2,4-trimethylpentane 17 .…”

Section: Discussionmentioning

confidence: 99%

Validation of a Vibrating-Wire Viscometer: Measurements in the Range of 0.5 to 135 mPa·s

et al. 2004

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The present article describes a novel vibrating-wire viscometer that has been shown to be able to measure viscosities up to 135 mPa‚s, after calibration against water at 20°C, to provide direct traceability to the primary reference for viscosity. For the purpose of validating the instrument, measurements of the viscosity of some selected fluids, including standard reference liquids with viscosity on the order of 100 mPa‚s at 20°C and 2,2,4-trimethylpentane with a viscosity of about 0.5 mPa‚s at the same temperature, were performed. The results obtained show that the instrument is capable of performing viscosity measurements with an estimated overall uncertainty better than (0.8% over the range of (0.5 to 135) mPa‚s.

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“…The water content before and after the viscosity measurements was (99 and 175) mg kg À1 , respectively. This correlation scheme was used previously to correlate viscosity data for dimethyl adipate [53], 2,2,4-trimethylpentane [56], HFC134a [57], toluene [58], HFC-143a and HFC-125 [59], R507 A [60], and for constructing a reference correlation for the viscosity of toluene [14] in wide ranges of temperature and pressure.…”

Section: Correlation Of the Viscosity With Density Using A Hard-sphermentioning

confidence: 99%

Tris(2-ethylhexyl) trimellitate (TOTM) a potential reference fluid for high viscosity. Part I: Viscosity measurements at temperatures from (303 to 373) K and pressures up to 65 MPa, using a novel vibrating-wire instrument

Diogo

Avelino

Caetano

et al. 2014

Fluid Phase Equilibria

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A B S T R A C TThe article reports viscosity measurements of compressed liquid tris(2-ethylhexyl) trimellitate or 1,2,4-Benzenetricarboxylic acid, tris(2-ethylhexyl) ester (TOTM) which is an important plasticizer in the polymer industry and has wide applications as a lubricant. Nevertheless, the main motivation for the present work is to propose TOTM as a plausible candidate for an industrial viscosity reference fluid for high viscosity, high pressure and high temperature. This kind of reference fluid is presently on demand by oil industries and the International Association for Transport Properties is developing efforts aiming to select appropriate candidates and to establish the corresponding reference data.The viscosity measurements were performed with a novel vibrating wire sensor. The new instrument was designed for operation at high pressures (up to 100 MPa) and temperatures up to 373 K. The present measurements were obtained using the vibrating wire sensor in the forced oscillation or steady-state mode of operation. The viscosity measurements were carried out up to 65 MPa and at six temperatures from (303 to 373) K.The viscosity results were correlated with density, using a modified hard-spheres scheme. The root mean square deviation of the data from the correlation is 0.53% and the maximum absolute relative deviation was less than 1.7%. The expanded uncertainty of the present viscosity results, at a 95% confidence level, is estimated to be less than AE2% for viscosities up to 68 mPa s, less than AE2.6% for viscosities between (69 and 268) mPa s and less than AE3% for higher viscosities.The TOTM density data necessary to compute the viscosity results were measured using a vibrating Utube densimeter, model DMA HP and are described in part II of the present work.No literature data above atmospheric pressure could be found for the viscosity of TOTM. As a consequence, the present viscosity results could only be compared upon extrapolation of the vibrating wire data to 0.1 MPa. Independent viscosity measurements were performed, at atmospheric pressure, using an Ubbelohde capillary in order to compare with the vibrating wire results, extrapolated by means of the above mentioned correlation. The two data sets agree within AE1%, which is commensurate with the mutual uncertainty of the experimental methods. Comparisons of the literature data obtained at atmospheric pressure with the present extrapolated vibrating-wire viscosity measurements have shown an agreement within AE2% for temperatures up to 339 K and within AE3.3% for temperatures up to 368 K.

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Density and Viscosity Measurements of 2,2,4-Trimethylpentane (Isooctane) from 198 K to 348 K and up to 100 MPa

Cited by 111 publications

References 25 publications

Validation and Divergence of the Activation Energy Barrier Crossing Transition at the AOT/Lecithin Reverse Micellar Interface

Validation and Divergence of the Activation Energy Barrier Crossing Transition at the AOT/Lecithin Reverse Micellar Interface

Validation of a Vibrating-Wire Viscometer: Measurements in the Range of 0.5 to 135 mPa·s

Tris(2-ethylhexyl) trimellitate (TOTM) a potential reference fluid for high viscosity. Part I: Viscosity measurements at temperatures from (303 to 373) K and pressures up to 65 MPa, using a novel vibrating-wire instrument

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