(208d) Group Contribution Estimation of Saft and Pc-Saft Parameters

The methodology of Elliott and Natarajan [J. R. Elliott, Jr., R. N. Natarajan, Ind. Eng. Chem. Res. 41 (2002) 1043] has been applied to statistical associating fluid theory (SAFT) [S. H. Huang, M. Radosz, Ind. Eng. Chem. Res. 22 (1990) 2284] and perturbed-chain statistical associating fluid theory (PC-SAFT) [J. Gross, G. Sadowski, Ind. Eng. Chem. Res. 40 (2001) 1244] equations of state to different families of compounds in order to describe their thermodynamic properties. Pure component parameters of each EOS are obtained through a regression method for a large number of compounds based on their boiling point temperatures at 10 and 760 mmHg, their estimated solubility parameter, liquid density, and standard hydrogen-bonding parameters. Then the group contribution (GC) to the SAFT and PC-SAFT shape factor parameters are obtained and presented for 88 functional groups. Hydrogen- bonding contributions based on a modified Wertheim theory [J. R. Elliott, Jr. Ind. Eng. Chem. Res. 35 (1996) 1624] are considered in this work. We have treated pure compounds of sixteen different families including: hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, alcohols, amines, nitriles, thiols, aldehydes, ethers, ketones, esters, halocarbons, hydroxyls, multi-functional groups, acids, sulfides and silicones. The average absolute percent deviation of saturated vapor pressure is 35.28% for GC-SAFT and 25.69% for GC-PC-SAFT equations. The average absolute difference between experimental and calculated saturated temperature are 12.7 K and 8.49 K for GC-SAFT and GC-PC-SAFT equations, respectively. These results are quite outstanding for a group contribution approach.