A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Experimental and theoretical studies on gas-phase reactions of NO3 radicals with three methoxyphenols: Guaiacol, creosol, and syringol
Abstract Methoxyphenols, lignin pyrolysis products, are major biomass combustion components and are considered potential tracers for wood smoke emissions. Their atmospheric reactivity, however, has not been well characterized. Guaiacol, creosol, and syringol are three typical methoxyphenols generated in relatively high concentrations in fresh wood smoke. In this study, the gas-phase reactions of NO3 radicals with these methoxyphenols were investigated using a laboratory-built vacuum ultraviolet photoionization gas time-of-flight mass spectrometer (VUV-GTOFMS) and off-line GC-MS. By combining experimental and theoretical methods, 4-nitroguaiacol, 6-nitroguaiacol, and 4,6-dinitroguaiacol were determined as the primary degradation products for guaiacol; similarly, 6-nitrocreosol and 3-nitrosyringol were identified for creosol and syringol, respectively. Using the relative rate method, rate constants at 298 K and 1 atm for the gas-phase reactions of guaiacol, creosol, and syringol with NO3 radicals were measured to be 3.2 × 10−12, 2.4 × 10−13, and 4.0 × 10−13 cm3 molecule−1 s−1, respectively. At a typical tropospheric concentration of NO3 radicals (5 × 108 molecule cm−3), atmospheric lifetimes for guaiacol, creosol, and syringol toward NO3 radicals were 0.2, 2.3, and 1.4 h, respectively. These results indicate that the reaction with NO3 radicals can be a major sink for methoxyphenols at night.
Highlights Reaction products of NO3 radical with three methoxyphenols are obtained. Nitro-substituted derivatives are observed as major transformation products. Reaction mechanisms of methoxyphenols with NO3 radicals are proposed. The rate constants of three methoxyphenols with NO3 radicals are measured.
Experimental and theoretical studies on gas-phase reactions of NO3 radicals with three methoxyphenols: Guaiacol, creosol, and syringol
Abstract Methoxyphenols, lignin pyrolysis products, are major biomass combustion components and are considered potential tracers for wood smoke emissions. Their atmospheric reactivity, however, has not been well characterized. Guaiacol, creosol, and syringol are three typical methoxyphenols generated in relatively high concentrations in fresh wood smoke. In this study, the gas-phase reactions of NO3 radicals with these methoxyphenols were investigated using a laboratory-built vacuum ultraviolet photoionization gas time-of-flight mass spectrometer (VUV-GTOFMS) and off-line GC-MS. By combining experimental and theoretical methods, 4-nitroguaiacol, 6-nitroguaiacol, and 4,6-dinitroguaiacol were determined as the primary degradation products for guaiacol; similarly, 6-nitrocreosol and 3-nitrosyringol were identified for creosol and syringol, respectively. Using the relative rate method, rate constants at 298 K and 1 atm for the gas-phase reactions of guaiacol, creosol, and syringol with NO3 radicals were measured to be 3.2 × 10−12, 2.4 × 10−13, and 4.0 × 10−13 cm3 molecule−1 s−1, respectively. At a typical tropospheric concentration of NO3 radicals (5 × 108 molecule cm−3), atmospheric lifetimes for guaiacol, creosol, and syringol toward NO3 radicals were 0.2, 2.3, and 1.4 h, respectively. These results indicate that the reaction with NO3 radicals can be a major sink for methoxyphenols at night.
Highlights Reaction products of NO3 radical with three methoxyphenols are obtained. Nitro-substituted derivatives are observed as major transformation products. Reaction mechanisms of methoxyphenols with NO3 radicals are proposed. The rate constants of three methoxyphenols with NO3 radicals are measured.
Experimental and theoretical studies on gas-phase reactions of NO3 radicals with three methoxyphenols: Guaiacol, creosol, and syringol
Yang, Bo (author) / Zhang, Haixu (author) / Wang, Youfeng (author) / Zhang, Peng (author) / Shu, Jinian (author) / Sun, Wanqi (author) / Ma, Pengkun (author)
Atmospheric Environment ; 125 ; 243-251
2015-11-12
9 pages
Article (Journal)
Electronic Resource
English
Methoxyphenol , NO<inf>3</inf> radical , Rate constant , Reaction mechanism , DFT , density functional theory , IRC , intrinsic reaction coordinate , POA , primary organic aerosol , SOA , secondary organic aerosol , VUV-GTOFMS , vacuum ultraviolet photoionization gas time-of-flight mass spectrometer
Theoretical studies on pyrolysis mechanism of guaiacol as lignin model compound
| American Institute of Physics | 2013