title: Vapour pressures, aqueous solubilities, Henry's Law constants, and octanol/water partition coefficients of a series of mixed halogenated dimethyl bipyrroles.
abstract: Basic physical-chemical properties of five bromine and chlorine containing mixed halogenated dimethyl bipyrroles (HDBPs) were determined using established methods. Subcooled liquid vapour pressures (P(o)(L,25)), aqueous solubilities (S(w,25)), and octanol/water partition coefficients (K(ow)) were determined using the gas chromatography-retention time, generator column, and slow-stirring methods, respectively. Henry's Law constants (H25) were estimated using experimentally-derived P(o)(L) and S(w,25) data. Values of all four properties were generally similar to those reported for other polyhalogenated aromatic compounds [P(o)(L,25) = (7.55-191) x 10(-6) Pa; S(w,25) = (1.0-1.9) x 10(-5) g/l; log K(ow) = 6.4-6.7; H25 = 0.0020-0.14 Pa m3/mol]. The effect of replacing a chlorine with a bromine atom significantly decreased P(o)(L,25) (log P(o)(L,25) = -0.4197 (# bromine atoms) - 2.643, p<0.01) and H25 (log H25 = -0.508 (# bromine atoms) + 0.394, p<0.02). There were no significant effects of bromine/chlorine substitution on S(w,25) or K(ow). A simple Level I equilibrium partitioning model predicted the environmental behaviour of HDBPs to be similar to a tetrabrominated diphenyl ether. Only slight differences in behaviour amongst HDBP congeners were predicted since substitution of a bromine for a chlorine (Cl/Br substitution) atom had less effect than H/Cl or H/Br substitution on P(o)(L,25), S(w,25), H25, and K(ow).
authors.affiliation: Centre for Analytical and Environmental Chemistry, Carleton University, Ottawa, Ont., Canada K1S 5B6. sheryl_tittlemier@hc-sc.gc.ca
authors.forename: Sheryl A
authors.initials: SA
authors.lastname: Tittlemier
authors.forename: Eric
authors.initials: E
authors.lastname: Braekevelt
authors.forename: Thor
authors.initials: T
authors.lastname: Halldorson
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Reddy
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Norstrom
mesh_terms: D017605:Bromine Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D017606:Chlorine Compounds / Q000737:chemistry*; D002849:Chromatography, Gas; D008956:Models, Chemical; D000442:Octanols / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry*; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D017605:Bromine Compounds; D017606:Chlorine Compounds; D000442:Octanols; D011758:Pyrroles; D014867:Water