Vapour–liquid coexistence properties and critical points of two branched alkanes series

Gibbs ensemble Monte Carlo (GEMC) simulations were used to estimate the orthobaric densities and critical points of two branched alkane series: the 2-methylalkanes and the 2,2-dimethylalkanes, using the recently proposed Nath, Escobedo, and de Pablo revised force field (NERD) [Nath et al., J. Chem. Phys. 108 (1998) 9905; Nath and de Pablo, Mol. Phys. 98 (2000) 231; Nath and Khare, J. Chem. Phys. 115 (2001) 10837]. Vapour–liquid coexistence curves were constructed for molecules containing up to 16 carbon atoms with very good correspondence to experimental data where it is currently available. Critical temperature, Tc, and critical density, ρc, values were also estimated from this data and compared with predictions from empirical correlations and group contribution methods.