Undecane and n-Alkylcyclohexanes Binary Mixtures: Densities and Speeds of Sound between 288.15 and 333.15 K and Viscosities between 293.15 and 323.15 K at 0.1 MPa

Abstract

The densities, dynamic viscosities, and speeds of the sound of mixtures of undecane with n-alkylcyclohexanes (methyl-, ethyl-, propyl-, butyl-, pentyl-, hexyl-, nonyl-, decyl-, and dodecylcyclohexane) were measured between 288.15 and 333.15 K and 0.1 MPa. Increasing temperature decreased the density, viscosity, and speed of sound. Increasing the concentration of components with higher property values produced mixtures with higher property values for most systems. Excess molar volumes (V m E’s) ranged from −0.33 to 0.17 cm3·mol–1. For equimolar mixtures, the V m E’s decreased as the n-alkyl chain length increased. Viscosity deviations based on a log-linear relationship (Δη’s) ranged from −0.04 to 0.22 mPa·s. The n-hexylcyclohexane mixtures produced the smallest Δη’s. Excess speeds of sound (c E’s) ranged from −3.3 to 12.4 m·s–1 and excess isentropic compressibilities (K s E’s) varied from −13.8 to 2.7 TPa–1. Ethylcyclohexane mixtures produced the smallest c E values and the largest K s E. The V m E’s and K s E’s for most mixtures were the same sign, thereby suggesting that the deviations in the volume occupied by the molecule affected the mixture compressibility. These data provide information to researchers who are seeking alternative mixtures to represent fuels and those looking at the impact of blendstock material on fuel behavior and molecular interactions.

Binary Mixtures of Nonane and n-Alkylcyclohexanes: Densities and Speeds of Sound within the Temperature Range (288.15–333.15) K and Viscosities at 288.15, 293.15, and 298.15 K and 0.1 MPa

“…Plots showing the deviation of the measured values from literature values for nonane are given in the Supporting Information (Figures S1 and S2). The remaining densities and speeds of sound used in this study have been previously published and can be found in the table of the mixture properties. ,,,, The viscosities of nonane and newly measured values for n -alkylcyclohexanes agree with many of the reported values within the expanded uncertainties of the measurement (Table ). The values for n -decyl and n -dodecylcyclohexanes are higher than those reported from 1953 ref .…”

“…For equimolar mixtures of alkylcyclohexanes and linear alkanes, the V m E s for nonane mixtures are lower than those reported for these alkylcyclohexanes in longer-chain hydrocarbons and higher than V m E s for octane in methylcyclohexane and n -butylcyclohexane, as shown in Figure A at 293.15 K. As the temperature increased, the excess molar volumes for all mixtures decreased. A Redlich–Kister-type expression, eq , was fitted to mixture V m E s according to procedures used in previous work V m E = x 1 x 2 ∑ i = 0 n A i ( x 1 − x 2 ) i …”

“…Comparison of excess properties or deviations of equimolar mixtures of alkylcyclohexanes in nonane in the current study (asterisk symbol) with those properties for alkylcyclohexanes in linear alkanes derived from literature properties: (A) excess molar volume V m E , (B) excess speed of sound c E , (C) excess isentropic compressibility K s E , and (D) viscosity deviation at 293.15 K. C alkyl chain is the number of carbon atoms on the alkyl chain of the cyclohexane. Values are based on data from Iloukhani and Rezaei-Sameti, Liu and Zhu, Luning Prak et al, − ,− Wang et al, and Baragi et al …”

“…Dynamic viscosity deviations (Δη) demonstrate how the mixture viscosity differs from a value predicted by a mixing rule, as shown in eqs and in Table . Previous studies with equimolar mixtures of linear alkanes and n -alkylcyclohexane have shown that mixture V m E s increase with increasing linear alkane size and decreasing n -alkylcyclohexane size. − The lowest c E s and highest K s E s have been found in mixtures of ethyl- or n -pentylcyclohexane with linear alkanes (undecane to hexadecane). − ,− The longer chain n -alkylcyclohexanes (from n -hexyl to n -decylcyclohexane) produce the lowest Δηs when mixed with linear alkanes (from undecane to hexadecane). − ,,,, …”

“…Nonane is a component of petroleum-based and alternative fuels − and has been shown to make up approximately 9 mass % of Fischer–Tropsch crude oil . Its importance in fuel research is illustrated by its inclusion in pyrolysis and oxidation kinetic models for fuels and by studies that have investigated its combustion behavior alone and with other fuel components, such as methylcyclohexane and methyl octanoate. − Many studies have explored the interaction of other linear alkanes found in fuel with alkylcyclohexanes through measurements of density, viscosity, and speed of sound, − but very few measurements have been made for nonane. ,, Density and viscosity values have been measured for mixtures of nonane with methylcyclohexane up to 308.15 K, , n -butylcyclohexane up to 313.15 K, and adamantane derivatives . The goal of this study was to measure the densities, viscosities, and speeds of sound for mixtures of nonane with n -alkylcyclohexanes with a range of alkyl chain lengths and place the data in relation to other linear alkane mixtures.…”