Selected Surface Tension Data and Recommended Correlations for Liquids with Cyclic Molecular Structures

Surface tension values for 94 liquids whose molecules include cyclic structures have been compiled from databases, books, and papers in the literature for different temperatures. These values were screened, and for each fluid the number of selected data ranges from 9 to 195, yielding a total of 2389 data points, of which 560 correspond to experimental ones. Recommended temperature-dependent correlations are proposed for 92 of the 94 substances considered, as the selected datasets for the remaining two exhibit significant discrepancies. The Guggenheim–Katayama analytical expression was applied using two or four adjustable coefficients, except for methylcyclopropane, for which six were required. The proposed correlations yield mean absolute deviations below 0.4 mN/m and mean absolute percentage deviations below 1.7%, except for 4-methylcyclopentene and 1-ethyltetralin, for which values around 2.3% were obtained. Moreover, percentage deviations below 9.1% are found for almost all selected data, with the only exceptions being two values for cyclopentane and one for 1-ethyltetralin, for which two different data sources provide different values at the highest temperatures. In general, the largest deviations are due to this kind of disagreement rather than to poor fitting by the correlation model. These new correlations expand the existing collection, which includes common substances, alcohols, refrigerants, organic acids, n-alkanes, esters, ethers, and alkenes, by incorporating 25 alkylcyclohexanes, 15 alkylcyclopentanes, 14 cycloaliphatic alcohols, 7 cycloalkanes, 13 cycloalkenes, 12 cyclobenzenes, and 6 multiring cycloalkanes, classified according to DIPPR nomenclature.