Collect. Czech. Chem. Commun. 1979, 44, 1918-1924

Distribution of dibenzyl sulfoxide between the aqueous and organic phases

František Vláčil and Huynh Dang Khanh

Department of Analytical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The distribution of dibenzyl sulfoxide (DBSO) between toluene or tetrachloromethane and aqueous solution of nitric, hydrochloric, or perchloric acid was investigated for different acid concentrations. The solubility of DBSO in the two solvents was established (0.0555 mol l-1 in toluene, 0.0121 mol l-1 in tetrachloromethane at 20 °C) and its distribution constants KD were determined for the systems toluene-water and CCl4-water (133.7 and 27.4, respectively, at 20 °C). Employing the dependence of the distribution ratio of DBSO on the Hammett function for nitric and perchloric acids solutions (1-6M) and taking into account the extraction of the solvates of these acids as described previously, the value of the DBSO protonation constant was calculated to be KH1 (B + H+ ##e BH+) = 1.00 . 10-2, and more accurate values of the extraction constants of the nitric acid solvates were obtained, Kex1 (HNO3 . B) 1.1 . 10-3 and Kex2 ((HNO3)2 . B) 4.3 . 10-5. Owing to the lower solubility of DBSO in water as well as in acid solutions as compared with aliphatic or cyclic sulfoxides and also with tri-n-butylphosphate, solution of DBSO in toluene suits better as the stationary phase for extraction chromatography of metal salts.