Thermodynamic properties of binary mixtures containing thiaalkanes. II. Thermal pressure coefficients of pure compounds at 298.15 K

An apparatus for the measurement of thermal pressure coefficients of pure compounds is described. The thermal pressure coefficient β of n-thiaalkanes R 2 S (R = CH 3 , C 2 H 5 , n-C 3 H 7 , n-C 4 H 9 , n-C 7 H 15 ) and of dithiaalkanes R 2 S 2 (R = CH 3 , C 2 H 5 , iso-C 3 H 7 ) were measured at 298.15 K and at zero pressure. These experimental results in conjunction with data from literature for other compounds are compared using the reduced parameter of pressure P* proposed by Flory. The P* do not have regular values for the lower members of thiaalkanes series. One explanation of these irregularities is the different size of the molecules.