Vapor pressures and enthalpies of vaporization for toxaphene congeners

Subcooled saturation liquid-phase vapor pressures (P-L) were determined for 21 chlorinated bornane and camphene congeners by capillary gas chromatography. Values of P-L for congeners with 6-10 chlorine substituents at 25 degreesC ranged from (0.23 to 7.1) mPa, and enthalpies of vaporization (Delta(vap)H) ranged from (77.6 to 91.8) kJ.mol(-1). Values of log P-L and Delta(vap)H were inversely correlated to chlorine number (r(2) = 0.883 and 0.854). When correlated versus molecular mass, P-L values of toxaphene congeners were slightly lower than those of other nonaromatic chlorinated pesticides (hexachlorocyclohexanes, cyclodienes) but higher than P-L values of aromatic chlorinated pesticides (DDT group compounds) and polychlorinated biphenyls (PCBs). The Delta(vap)H values of toxaphene congeners and other nonaromatic chlorinated pesticides were similar, and both groups of compounds had Delta(vap)H values lower than those for DDTs and PCBs. Relationships of log P-L and Delta(vap)H to chlorine positioning followed published trends with relative retention index on a nonpolar GC column.