2007
Photochemically induced nitration and hydroxylation of organic aromatic compounds in the presence of nitrate or nitrite in ice.
MATYKIEWICZOVÁ, Nina, Romana KURKOVÁ, Jana KLÁNOVÁ a Petr KLÁNZákladní údaje
Originální název
Photochemically induced nitration and hydroxylation of organic aromatic compounds in the presence of nitrate or nitrite in ice.
Název česky
Fotochemicky indukovaná nitrace a hydroxylace aromatických organických sloučenin v přítomnosti dusičnanů a dusitanů v ledu.
Autoři
MATYKIEWICZOVÁ, Nina (203 Česká republika), Romana KURKOVÁ (203 Česká republika), Jana KLÁNOVÁ (203 Česká republika) a Petr KLÁN (203 Česká republika, garant)
Vydání
Journal of Photochemistry and Photobiology A: Chemistry, Amsterdam, The Netherlands, Elsevier Science, 2007, 1010-6030
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10401 Organic chemistry
Stát vydavatele
Nizozemské království
Utajení
není předmětem státního či obchodního tajemství
Impakt faktor
Impact factor: 1.911
Kód RIV
RIV/00216224:14310/07:00020855
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000244833600003
Klíčová slova anglicky
Photochemistry; Ice; Snow; Nitrate; Nitrite; Aromatic compounds; Phenol; Nitration; Oxidation.
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 23. 6. 2009 15:13, prof. RNDr. Petr Klán, Ph.D.
V originále
The photochemistry of three model aromatic compounds (phenol, anisole, and 4 methoxyphenol; c = 0.001 mol/L) in frozen aqueous solutions containing sodium nitrite or nitrate (from c = 0.01 to 0.1 mol/L) at minus 15 C was investigated. Nitration, hydroxylation, and coupling reactions were found to be the principal chemical processes, presumably taking place in the quasi-liquid layer covering the ice crystal surfaces where both hydrophobic organic and water soluble inorganic compounds were accumulated prior to irradiation. While primary photoproducts were identified at low reaction conversions, exhaustive (quartz or Pyrex filtered) UV irradiation produced a very complex mixture of secondary photoproducts. The photoreactions proceeded predominantly by the nitrite or nitrate photoexcitation but chemistry of the excited organic chromophores was also observed. Phenol and 4 methoxyphenol photolysis afforded the corresponding nitro and hydroxycompounds, as well as biphenyl and diphenylether derivatives. The presence of nitrite or nitrate caused that qualitatively the same photoproducts were produced; therefore both were the source of the NOx or HO radicals. In contrast, irradiation of anisole under the same reaction conditions afforded phenol nearly exclusively. It is demonstrated that the OH group of phenols played an important role in the course of hydroxylation and nitration reactions. The results from this study may support assumptions according to which photolysis of nitrate in the snowpack is responsible for oxidation of organic precursors to their hydroxy or carbonyl derivatives.
Česky
The photochemistry of three model aromatic compounds (phenol, anisole, and 4 methoxyphenol; c = 0.001 mol/L) in frozen aqueous solutions containing sodium nitrite or nitrate (from c = 0.01 to 0.1 mol/L) at minus 15 C was investigated. Nitration, hydroxylation, and coupling reactions were found to be the principal chemical processes, presumably taking place in the quasi-liquid layer covering the ice crystal surfaces where both hydrophobic organic and water soluble inorganic compounds were accumulated prior to irradiation. While primary photoproducts were identified at low reaction conversions, exhaustive (quartz or Pyrex filtered) UV irradiation produced a very complex mixture of secondary photoproducts. The photoreactions proceeded predominantly by the nitrite or nitrate photoexcitation but chemistry of the excited organic chromophores was also observed. Phenol and 4 methoxyphenol photolysis afforded the corresponding nitro and hydroxycompounds, as well as biphenyl and diphenylether derivatives. The presence of nitrite or nitrate caused that qualitatively the same photoproducts were produced; therefore both were the source of the NOx or HO radicals. In contrast, irradiation of anisole under the same reaction conditions afforded phenol nearly exclusively. It is demonstrated that the OH group of phenols played an important role in the course of hydroxylation and nitration reactions. The results from this study may support assumptions according to which photolysis of nitrate in the snowpack is responsible for oxidation of organic precursors to their hydroxy or carbonyl derivatives.
Návaznosti
| GA205/05/0819, projekt VaV |
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| MSM0021622412, záměr |
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