Vapour pressures and the molar enthalpies of vaporization D g l H m of the linear aliphatic acetates C 8 -C 16 have been determined by the transpiration method. KovatÕs indices of these compounds were measured by capillary gas-chromatography. A linear correlation of enthalpies of vaporization D g l H m at T = 298.15 K of the acetates studied with the KovatÕs indices as well as with the number of carbon atoms has been found.

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The standard molar enthalpies of vaporization of 11 branched tert-butyl alkyl ethers, tert-amyl alkyl ethers, and tert-octyl alkyl ethers have been determined from the temperature dependence of the vapor pressure measured by the transpiration method. The temperature dependences of retention indices for a set of 31 ethers with branched molecular structures were measured using a nonpolar gas chromatographic column. Values of for 13 ethers obtained from the transpiration method in this work (as well as some values selected from the literature) together with data for these ethers obtained from the correlation gas-chromatography method were used to derive a correlation for the prediction of the standard molar enthalpies of vaporization for branched ethers at the temperature T = 298.15 K. Experimental values of for 19 branched ethers were obtained with the help of this correlation. The procedure of the correlation gas-chromatography method was modified and substantially simplified by introduction of the Kovat's index for the correlation of the retention indices with the experimental .

Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic dimethyl esters of dicarboxylic acids CH3-CO2-(CH2) n -CO2-CH3 with n = (0 to 8) have been determined by the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the esters studied with the number n and with the Kovat's indices and has been found. The critical temperatures and pressures of the esters with n = (0 to 6) and n = 8 have been measured by the pulse-heating method with the residence times ranging from (0.03 to 1) ms. Experimental data on the critical properties are compared with the estimations by group contribution methods by Constantinou and Gani and by Marrero and Gani. Both methods considerably underestimate the critical temperatures of the esters studied; however, the method by Marrero and Gani provides the prediction of the critical pressures of the esters with an average absolute error approximately equal to the uncertainty of the measurements.