Effects of Chain Length, Chlorination Degree, and Structure on the Octanol−Water Partition Coefficients of Polychlorinated n-Alkanes

Abstract

Log octanol−water partition coefficients (log K_ow) of 40 synthesized polychlorinated n-alkanes (PCAs) with different chlorination degrees were determined using reversed-phase high performance liquid chromatography (RP-HPLC). In addition, log K_ow values of a technical mixture namely Cereclor 63L as well as 15 individual in house synthesized C₁₀, C₁₁, and C₁₂ chloroalkanes with known chlorine positions were estimated. Based on these results, the effects of chain length, chlorination degree, and structure were explored. The estimated log K_ow values ranged from 4.10 (polychlorinated n-decanes with 50.2% chlorine content) to 11.34 (polychlorinated n-octacosanes with 54.8% chlorine content) for PCAs and from 3.82 (1,2,5,6,9,10-hexachlorodecane) to 7.75 (1,1,1,3,9,11,11,11-octachlorododecane) for the individual chloroalkanes studied. The results showed that log K_ow value was influenced linearly at a given chlorine content by chain length, while a polynominal effect was observed in dependence on the chlorination degree of an alkane chain. Chlorine substitution pattern influenced markedly the log K_ow value of chloroalkanes.