Speed of Sound and Derived Properties of Ethyl Nonanoate

Abstract

Ethyl nonanoate is a promising component of biodiesel with a satisfactory cetane number and reactivity. The speeds of sound in ethyl nonanoate were measured by the Brillouin light scattering (BLS) method within the temperatures from 295.24 to 593.15 K and at pressures up to 10 MPa. The relative expanded uncertainty (k = 2) of our BLS experimental system is estimated to be less than 0.7%. The densities of ethyl nonanoate were measured using a vibrating tube densimeter at atmospheric pressure in the temperature range of 293.15–353.15 K, and the absolute average relative deviation between the experimental densities and the literature data is 0.12%. For temperatures between 303.15 and 353.15 K and at pressures up to 10 MPa, these measurements were used to calculate densities, isobaric heat capacities, and indirect derivative properties including the isobaric thermal expansion, the isothermal compressibility, the isentropic compressibility, and the internal pressure. The comparison between the calculated isobaric heat capacities and the literature values shows a satisfactory agreement with an absolute average relative deviation of 0.18% and a maximum deviation of 0.38%. At the end, the dependences of internal pressure of ethyl nonanoate on temperature and pressure were found to be in accordance with those of ethyl caprylate and ethyl caprate.

Speed of Sound and Derivative Properties of Ethyl Laurate from Rayleigh–Brillouin Light-Scattering Spectroscopy

“…The calculated isentropic compressibilities and isothermal compressibilities obtained here were compared with those data presented by Habrioux et al in the temperature range of 313.15 to 353.15 K at pressures up to 10.0 MPa, yielding absolute AADs of 0.25% (MD = 0.64%) and 0.60% (MD = 1.57%), respectively. In terms of a certain state among the investigated p - T region for saturated fatty acid ethyl esters including ethyl nonanoate, ethyl decanoate, and ethyl laurate, with the increase of carbon chain length, the speed of sound and heat capacity increase, while the density, isentropic compressibility, isobaric thermal expansivity, isothermal compressibility, and internal pressure decrease. As for methyl laurate and ethyl laurate, the ranked increase in the isentropic compressibility, heat capacity, isothermal compressibility, and isobaric thermal expansivity is found to be of order ethyl laurate > methyl laurate, and the order of decreasing speed of sound, density, and internal pressure is ethyl laurate < methyl laurate .…”

“…To obtain the main contribution of the pressure dependence of density, the experimental speeds of sound in ethyl laurate were correlated as a function of temperature and pressure using the following rational equation 19,40…”

“…The dependences of the internal pressure of ethyl laurate on temperature and pressure are similar to those of alkanes, dibromoalkanes, and ethyl nonanoate. 40,43,44 The distance between the surfaces of molecules is called the intermolecular free length, which can be used to evaluate intermolecular repulsive forces between molecules with clear physical significance. 45 The intermolecular free length (L f ) under atmospheric pressure can be defined as follows 46,47 ρ ρ…”

“…To obtain the main contribution of the pressure dependence of density, the experimental speeds of sound in ethyl laurate were correlated as a function of temperature and pressure using the following rational equation , where A 0 , A 1 , A 2 , A 3 , B 1 , B 2 , B 3 , C , and D are adjustable parameters, which are given in Table . To evaluate the accuracy of fitting expressions and computational formulas, the relative deviation (RD), the absolute average percentage deviation (AAD), and the maximum deviation (MD) are introduced in the following forms where y cal, i is the i th value calculated from the fitting expression and y exp, i is the i th value of experimental results or literature data.…”

Thermo-Acoustic Properties of (Ethanol + n-Heptane) Binary Mixtures from 293.35 to 433.89 K and up to 5.0 MPa

“…Since the specific isobaric heat capacity varies slightly with pressure, eq is sufficiently accurate when the pressure difference (Δ p ) is taken as 0.1 MPa. , Furthermore, the simultaneous step-by-step integration in eq requires the temperature dependences of density and specific isobaric heat capacity at initial pressure, which is 0.1 MPa here. The density of ethanol (1) + n -heptane (2) reported by Dzida et al with a precision of 0.05 kg·m –3 was adopted.…”