2006
Enhanced Protonation of Cresol Red in Acidic Aqueous Solutions Caused by Freezing
HEGER, Dominik, Jana KLÁNOVÁ a Petr KLÁNZákladní údaje
Originální název
Enhanced Protonation of Cresol Red in Acidic Aqueous Solutions Caused by Freezing
Název česky
Protonace Kresolové červeně v zamrzlých vodných roztocích
Autoři
HEGER, Dominik (203 Česká republika), Jana KLÁNOVÁ (203 Česká republika) a Petr KLÁN (203 Česká republika, garant)
Vydání
Journal of Physical Chemistry B, USA, The American Chemical Society, 2006, 1089-5639
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10401 Organic chemistry
Stát vydavatele
Spojené státy
Utajení
není předmětem státního či obchodního tajemství
Impakt faktor
Impact factor: 3.047
Kód RIV
RIV/00216224:14310/06:00015811
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000235046300030
Klíčová slova anglicky
Photochemistry; ice; cresol red; spectroscopy
Štítky
Příznaky
Mezinárodní význam
Změněno: 23. 6. 2009 15:17, prof. RNDr. Petr Klán, Ph.D.
V originále
The protonation degree of cresol red (CR) in frozen aqueous solutions at 253 or 77 K, containing various acids (HF, HCl, HNO3, H2SO4, and p-toluenesulfonic acid), sodium hydroxide, NaCl, or NH4Cl, was examined using UV/Vis absorption spectroscopy. CR, a weak organic diacid, has been selected as a model system to study the acid-base interactions at the grain boundaries of ice. The multivariate curve resolution alternating least-squares method was used to determine the number and abundances of chemical species responsible for the overlaying absorption visible spectra measured. The results showed that the extent of CR protonation, enhanced in the solid state by 2-4 orders of magnitude in contrast to the liquid solution, is principally connected to an increase in the local concentration of acids. It was found that this enhancement was not very sensitive to either the freezing rate or the type of acid used and that CR apparently established an acid-base equilibrium prior to solidification. In addition, the presence of inorganic salts, such as NaCl or NH4Cl, is reported to cause a more efficient deprotonation of CR in the former case and an enhanced protonation in the latter case, being well explained by the theory of Bronshteyn and Chernov. CR thus served as an acid-base indicator at the grain boundaries of ice samples. Structural changes in the CR molecule induced by lowering the temperature and a presence of the constraining ice environment were studied by the absorption and 1H NMR spectroscopies. Cryospheric and atmospheric implications concerning the influence of acids and bases on composition and reactivity of ice or snow contaminants were examined.
Česky
Protonace Kresolové červeně v zamrzlých vodných roztocích
Návaznosti
| GA205/05/0819, projekt VaV |
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| MSM0021622412, záměr |
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