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 KLÁN. Photochemically induced nitration and hydroxylation of organic aromatic compounds in the presence of nitrate or nitrite in ice. Journal of Photochemistry and Photobiology A: Chemistry. Amsterdam, The Netherlands: Elsevier Science, 2007, roč. 187, č. 187, s. 24-32. ISSN 1010-6030.

Základní 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

• Originální 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: Aromatic compounds, ice, nitrate, Nitration, nitrite, oxidation., PHENOL, Photochemistry, snow
• Příznaky: Mezinárodní význam, Recenzováno

Anotace

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.

Anotace 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: Název: Environmentální důsledky fotochemických transformací v ledu a sněhu

Investor: Grantová agentura ČR, Environmentální důsledky fotochemických transformací v ledu a sněhu

• MSM0021622412, záměr: Název: Interakce mezi chemickými látkami, prostředím a biologickými systémy a jejich důsledky na globální, regionální a lokální úrovni (INCHEMBIOL) (Akronym: INCHEMBIOL)

Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, Interakce mezi chemickými látkami, prostředím a biologickými systémy a jejich důsledky na globální , regionální a lokální úrovni