Heat capacities at constant pressure of five R,ω-dichloroalkanes (1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobutane, 1,5-dichloropentane, 1,6-dichlorohexane) were measured at temperatures ranging from 284 K to 353 K by using a highly sensitive Tian-Calvet differential scanning microcalorimeter (DSC). Changes in the standard procedures increased the accuracy of C p measurements. The influence of the evaporation heat effect on the C p value is analyzed. In the described method, the uncertainty of the measurements is estimated to be (0.15% for uncertainties arising solely from the measurement system and method. The group contributions to C p for CH 2 and Cl and their temperature dependence were determined by a group additivity analysis.

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The components of biodiesel derived from coconut oil or babassu oil such as ethyl caprylate and ethyl caprate are studied. The experimental speeds of sound in ethyl caprylate were reported at p = (0.1 to 101.32) MPa and at T = (292.90 to 318.32) K and in ethyl caprate at p = (0.1 to 101.32) MPa and at T = (292.90 to 318.28) K together with the experimental densities at 0.1 MPa for ethyl caprylate at T = (278.15 to 358.15) K and for ethyl caprate at T = (283.15 to 353.14) K as well as heat capacities were reported at 0.1 MPa for ethyl caprylate at T = (285.01 to 343.78) K and for ethyl caprate at T = (286.16 to 341.11) K. The density, adiabatic and isothermal compressibilities, heat capacity, isobaric thermal expansion, and internal pressure at elevated pressures and temperatures were calculated from the experimental results in the way described by Davis and Gordon (J. Chem. Phys. 1967Phys. , 46, 2650Phys. −2660 with the aim of studying the effect of changing of the carbon chain length from ethyl caprylate to ethyl caprate on pressure and temperature dependence of above-mentioned properties. Moreover, densities of ethyl caprylate and ethyl caprate were compared with densities of ethyl laurate and ethyl myristate to improve intersection of their isotherms.

The heat capacities at constant pressure of 1,2-ethanediol (1,2-EtD), 1,3-propanediol (1,3-PrD), 1,4-butanediol (1,4-BuD), 1,5-pentanediol (1,5-PeD), and 1, were measured within the temperature range from (293.15 to 353.15) K. The heat capacities of three other compounds, 1,6-hexanediol (1,6-HxD), 1,8-octanediol (1,8-OcD), and 1,9-nonanediol (1,9-NoD), were also measured between their melting point and 353.15 K. All measurements were performed by means of a DSC III (Setaram) differential scanning calorimeter. Assuming that the molar heat capacity shows an additive character, a simple equation was proposed that allows one to describe C p values of liquid R,ω-alkanediols as a function of temperature and the alkyl chain length with an accuracy below 1 %.