2ND CROSS VIRIAL-COEFFICIENT OF THE BINARY VAPOR MIXTURE N-HEXANE METHANOL FROM QUASI-ISOCHORIC PPT MEASUREMENTS/

Quasi-isochoric p rho T measurements on n-hexane/methanol mixtures wer e carried out in the low-density region by means of a constant-volume quartz glass cell. Eight isochores were measured in the temperature ra nge from 347 up to 600 K at densities between 35 and 57 mol m(-3). Val ues of the second cross virial coefficient B-12 of n-hexane/methanol w ere derived and used to develop a correlation for the representation o f its temperature dependence. The abilities of the scheme by Tsonopoul os, based on the theorem of corresponding states, and of the group con tribution method by Brandani et al. were tested to predict B-12 for th e n-hexane/methanol system. A relationship for the interaction paramet er k(12) of the Tsonopoulos scheme was developed for binary mixtures o f non-polar components with methanol. Furthermore, the parameter for t he interaction between CH2 and CH3OH groups within the Brandani method was determined to be used for binary systems of methanol with n-alkan es.