Molar refractivity and connectivity index correlations for Henry's law virial coefficients of odorous sulfur compounds on carbon and for gas-chromatographic retention indices

Gas-solid chromatography was used to obtain values of the second gas-solid virial coefficient, B-2s, in the temperature range from 392 to 511 K for 10 volatile, malodorous organic sulfur compounds; ethanethiol, 1-propanethiol , methyl sulfide, 2-propanethiol, 1-methyl-1-propanethiol, 2-methyl-1-propa nethiol, 2-methyl-2-propanethiol, ethyl sulfide, ethyl methyl sulfide, and tert-butyl methyl sulfide. Carbopack C (Supelco Inc.), a graphitized carbon black powder, was used as the adsorbent. Beginning with a theoretical equa tion for the second gas-solid virial coefficient, it was shown how a quanti tative structure-retention relation (QSRR) could be developed to correlate In Bz, and hence chromatographic retention times with calculated molar refr activity and connectivity index values for the thiols and thioethers. It wa s found that both the gas-solid interaction energies and the In Bz, values could be correlated with calculated adsorbate molar refractivity (r(2) = 0. 951) and (r(2) = 0.961), respectively. Connectivity index and molar refract ivity together provide a r(2) = 0.989 correlation of the ten In By values a t 403 K. A set of 373 organic compounds with retention indices taken from t he literature was used to further test our approach. The 373 molecules were divided into 10 structural subgroups and molar refractivities and connecti vity indices were calculated and used to correlate their retention index va lues. An overall correlation of r(2) = 0.982 for the retention indices of t he 373 molecules was found. (C) 2001 Academic Press.