Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3 CH2 Cl)

Atmospheric chemistry of (CF3)2C=CH2: OH radicals, Cl atoms and O3 rate coefficients, oxidation end-products and IR spectra.

The rate coefficients for the gas phase reactions of OH radicals, k1, Cl atoms, k2, and O3, k3, with 3,3,3-trifluoro-2(trifluoromethyl)-1-propene ((CF3)2C=CH2, hexafluoroisobutylene, HFIB) were determined at room temperature and atmospheric pressure employing the relative rate method and using two atmospheric simulation chambers and a static photochemical reactor. OH and Cl rate coefficients ob...

Hfc - 23 Emissions from Hcfc - 22 Production

The compound HFC-23 (Trifluoromethane or CHF3), a potent greenhouse gas with a 100-year global warming potential of 11,700, is generated as a by-product during the manufacture of HCFC-22 (chlorodifluoromethane or CHClF2). This paper outlines options and issues for good practice guidance in the national inventory management of HFC-23 emissions from HCFC-22 production. The issues presented are or...

Photochemical deactivation process of HCFC-133a (C2H2F3Cl): a nonadiabatic dynamics study.

The photochemical deactivation process of HCFC-133a (C2H2F3Cl) was investigated by computing excited-state properties with a number of single-reference methods, including coupled cluster to approximated second order (CC2), algebraic diagrammatic construction to second order (ADC(2)), and time-dependent density functional theory (TDDFT). Excited states calculated with these methods, especially T...

H-c-o-oc-ch2-ch2-ch2-ch2-ch2-ch2-ch2-ch2- Ch2-ch2-ch2- Ch2-ch2-ch2-ch2-ch2-ch3 | H-c-o-oc-ch2-ch2-ch2-ch2-ch2-ch2-ch2-ch = Ch-ch2-ch2- Ch2-ch2-ch2-ch2-ch2-ch3

Atmospheric transformation of diesel emissions.

The hypothesis of this study was that exposing diesel exhaust (DE*) to the atmosphere transforms its composition and toxicity. Our specific aims were (1) to characterize the gas- and particle-phase products of atmospheric transformations of DE under the influence of daylight, ozone (O3), hydroxyl (OH) radicals, and nitrate (NO3) radicals; and (2) to explore the biologic activity of DE before an...