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Densities, speeds of sound, and refractive indices of methyl laurate, ethyl laurate, ethyl myristate, and ethyl oleate in the temperature range 288.15−343.15 K and viscosities from 288.15 to 373.15 K were measured at atmospheric pressure. The measured properties were in good agreement with several available literature data, finding an overall absolute average percentage deviation (AAD) of 0.04%, 0.07%, 3%, and 0.1% for density, speed of sound, viscosity, and refractive index, respectively. The densities of mentioned esters were also measured along 15 isotherms from 293.15 to 413.15 K and at pressures up to 60 MPa using an Anton Paar DMA HP densimeter. Based on the literature data selected for comparison, in the studied ranges of temperature and pressure, the AADs of high-pressure densities were 0.08% for methyl laurate, 0.06% for ethyl laurate, and 0.05% for ethyl myristate. The obtained density values were correlated through the modified Tammann−Tait equation with an AAD lower than 0.009% for all the studied esters. The adjusted parameters were used to calculate the isothermal compressibility, isobaric thermal expansivity, internal pressure, and difference in isobaric and isochoric heat capacities. It was found that methyl laurate has higher density, speed of sound, and refractive index than ethyl laurate of the same fatty acid, while viscosities for the ethyl are slightly higher than those of the methyl laurate. The values of the isothermal compressibility and the isobaric thermal expansivity for ethyl laurate are slightly higher than those for methyl.

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Densities data of n-hexane, toluene and dichloromethane at temperatures 288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work, were fitted to the modified Tait equation of state. The fitted temperature-pressure dependent density data were used to calculate the derived properties: the isothermal compressibility, the isobaric thermal expansivity, the difference between specific heat capacity at constant pressure and at constant volume and the internal pressure, over the entire temperature and pressure intervals specified above. In order to assess the proposed modeling procedure, a comparison of the obtained values for the isothermal compressibility and the isobaric thermal expansivity with the corresponding literature data were performed. The average absolute percentage deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric thermal expansivity: for n-hexane 1.31-4.17%, for toluene 0.71-2.45% and for dichloromethane 1.16-1.61%. By comparing the obtained deviations values with those found in the literature it can be concluded that the presented results agree good with the literature data. [Projekat Ministarstva nauke Republike Srbije, br. 172063]

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In this work an apparatus for density measurements in the compressed liquid regions was presented. This installation is based on the use of the DMA HP density measuring cell and the DMA 5000 densimeter (both instruments are products of Anton Paar, Gratz, Austria). Calibration of DMA HP cell was performed by applying the classical method where a vacuum, water and n-decane were recommended to be used as calibration fluids. To test the capabilities of the set-up, the densities of n-hexane, toluene and dichloromethane were measured in the temperature interval 288.15 to 413.15 K and the pressure range 0.1-60 MPa. The obtained results were compared with the corresponding values found in the literature. Depending on the literature selected for comparison (the temperature and pressure ranges available) the average absolute percentage deviations were: for n-hexane 0.03-0.10%; for toluene 0.04-0.08% and for dichloromethane 0.02-0.03%. A deeper insight into the results of this work shows that most of them are in a good agreement with the literature values; higher discrepancies are remarked in the vicinity of the ends of the temperature and pressure ranges. [Projekat Ministarstva nauke Republike Srbije, br. 172063]

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