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Micro liquid-liquid extraction of acetyl derivatives of phenols

Urbanczyk A., Staniewski J., Apostoluk W., Szymanowski J.

Chemia Analityczna

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2002

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Vol. 47, No. 5

669-679

EN

Micro liquid-liquid extraction of phenols acetyl derivatives from aqueous solution was studied and distribution coefficient was successfully correlated with solvent and solute property parameters. Toluene selected as a solvent for the extraction proved to be appropriate for the process. Extraction depended mainly on the hydrophobicity of phenol acetyl derivatives and the ionic strength of the aqueous solution. With the use of large volume on-column sample introduction technique it was possible to determine phenols at the level of 1 ug L(-1) both in model and environmental samples with a flame ionization detector.

PL

Zastosowano metodę mikroekstrakcję ciecz-ciecz do wydzielania fenoli z próbek wodnych. Fenole ekstrahowano w postaci pochodnych acetylowych, przeprowadzając derywatyzację bezpośrednio w próbce wodnej za pomocą bezwodnika kwasu octowego. Wyznaczono współczynniki podziału acetylowych pochodnych fenoli pomiędzy fazę wodną i organiczną, które z powodzeniem skorelowano z parametrami rozpuszczalników oraz badanych związków. Odpowiednim ekstrahentem do tego celu okazał się toluen. Ekstrakcja zależała głównie od hydrofobowości acetylowych pochodnych fenoli oraz siły jonowej roztworu wodnego. Dozowanie próbki o dużej objętości metodą on-column pozwoliło na oznaczanie fenoli na poziomie l ug L(-1), zarówno w przypadku modelowych próbek wodnych, jak i próbek środowiskowych, przy zastosowaniu detektora płomieniowo-jonizacyjnego.

2

Hydrogen bonded complexes of coumarin 153

Królicki R., Jarzęba W., Soroushian B., Lampre I., Mostafavi M.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 4

435-449

EN

Detailed studies of the hydrogen-bonded complexes of coumarin 153 (C153) have been carried out. It has been shown that nonlinear shifts of the steady-state absorption and fluorescence spectra taken in toluene-methanol solvent mixtures are caused by the formation of hydrogen bonded complexes between C153 and methanol, while preferential solvation plays a minor role only. IR measurements confirmed the ability of C153 to form hydrogen-bonded complexes with methanol and phenol. The stoichiometry of the formed complexes and relevant equilibrium constants have been estimated. Femtosecond solvation dynamics measurements of C153 in the toluene-methanol mixture (xMeOH = 0.2) showed that the average solvation time is higher than that in the pure solvents indicating slower relaxation of methanol in the mixture. The slow component of solvation dynamics (ok 20ps) can be attributed to translational diffusion of methanol to the first solvation shell of C153 and to the relatively slow reorientational motion of methanol involved in formation of hydrogen bond with the excited C153.

3

Solvation and proton transfer phenomena in phenol derivative-tertiary amine-aprotic solvent systems

Ilczyszyn M.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 1

91-100

EN

Proton transfer (PT) equilibria inside hydrogen-bonded complexes of phe-nols (AH) with triethylamine and JV-methylpiperidine (B), A-H...B A - o -H-B+, dissolved in cooled (up to 113 K) aprotic solvents are analysed using H NMR results. Two categories of situations, depending on the acid and base initial concentrations, are considered: slower and faster PT for the Cg : CAg w 2 and Cg : CAu > 2 solutions, re-spectively. They are characterised by enthalpy and entropy of PT and interpreted as a result of relations between the proton transfer and solvation phenomena. In strongly cooled CB : CAH Ť 2 solutions the intra-complex proton motion is probably coupled to the motion of the solvating base molecule. This phenomenon is qualitatively described by the density function of the energy attraction between the bridging AHB proton and the solvating amine molecule. In the CB : CAH > 2 solutions this mechanism does not work probably and the hydrogen bonded ion-pairs are strongly solvated by the neighbour amine molecules.