Oscar Herrera Amézquita | Universidad Peruana Cayetano Heredia (original) (raw)
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Papers by Oscar Herrera Amézquita
The supercooled liquid vapor pressures P L of 23 polybrominated diphenyl ether congeners were det... more The supercooled liquid vapor pressures P L of 23 polybrominated diphenyl ether congeners were determined as a function of temperature with a gas chromatographic retention time technique. P L at 298.15 K ranged from 0.1 Pa for monobrominated diphenyl ethers to 10-6 Pa for heptabrominated diphenyl ethers. The halogen substitution pattern was found to influence PBDE vapor pressure, indicating that congeners with bromine substitutions in the ortho positions to the ether-link have higher vapor pressures. The enthalpy of vaporization ∆ vap H for the 23 PBDE congeners ranged from (-67 to-116) kJ/mol, decreasing with each additional bromine substitution by about (7 to 8) kJ‚mol-1. ∆ vap H was also found to be influenced by the number of ortho bromines. Using a Junge-Pankow approach, the fraction of chemical adsorbed to aerosols as a function of temperature was estimated for three congeners and used to speculate on the likely environmental behavior of these chemicals.
The supercooled liquid vapor pressures P L of 23 polybrominated diphenyl ether congeners were det... more The supercooled liquid vapor pressures P L of 23 polybrominated diphenyl ether congeners were determined as a function of temperature with a gas chromatographic retention time technique. P L at 298.15 K ranged from 0.1 Pa for monobrominated diphenyl ethers to 10-6 Pa for heptabrominated diphenyl ethers. The halogen substitution pattern was found to influence PBDE vapor pressure, indicating that congeners with bromine substitutions in the ortho positions to the ether-link have higher vapor pressures. The enthalpy of vaporization ∆ vap H for the 23 PBDE congeners ranged from (-67 to-116) kJ/mol, decreasing with each additional bromine substitution by about (7 to 8) kJ‚mol-1. ∆ vap H was also found to be influenced by the number of ortho bromines. Using a Junge-Pankow approach, the fraction of chemical adsorbed to aerosols as a function of temperature was estimated for three congeners and used to speculate on the likely environmental behavior of these chemicals.