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104 results on '"Parkanyi, C."'

18. GC/MS Analysis of the Volatile Constituents of Corymbia citriodora Hook. from Réunion Island.

Author

Vernin, G. A., Parkanyi, C., Cozzolino, F., and Fellous, R.

Subjects
*ESSENTIAL oils, *DISTILLATION, *CITRONELLA oil, *ACETATES, *HYDROCARBONS, *MENTHONE, *PLANT extracts
Abstract

A hydrodistilled oil from Corymbia citriodora Hook. produced from leaves harvested in the Réunion Island was analyzed by GC and GC/MS on nonpolar and polar columns, respectively. Nearly 100 constituents were identified. The major constituents were citronellal (63.6%), α-citronellol (7.3%), sopulegol isomers (6.5%), citronellyl acetate (2.6%), p-cymene (2.5%), citronellal dimmers (2.5%), alpha;-pinene (2.1%) and β-caryophyllene (1.2%). Several esters of isobutyric acid (4), monoterpene- (18), and sesquiterpene (15) hydrocarbons, oxides (6), monoterpene alcohols (10), esters (8) and aldehydes (4), (Z)-jasmone, citronellyl citronellate, citronellic acid, eugenol, and some aliphatic and alicyclic derivatives, were presented in trace amounts. On the polar column, further constituents were identified, including menthone, isomenthone, 4-vinylguiacol, and two heavy aliphatic acids: myristic and palmitic acids. [ABSTRACT FROM AUTHOR]

Published
2004
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19. GC/MS Analysis of the Volatile Constituents of Corymbia citriodoraHook. from Réunion Island

Author

Vernin, G.A., Parkanyi, C., Cozzolino, F., and Fellous, R.

Abstract

AbstractA hydrodistilled oil from Corymbia citriodoraHook. produced from leaves harvested in the Réunion Island was analyzed by GC and GC/MS on nonpolar and polar columns, respectively. Nearly 100 constituents were identified. The major constituents were citronellal (63.6%), α-citronellol (7.3%), isopulegol isomers (6.5%), citronellyl acetate (2.6%), p-cymene (2.5%), citronellal dimmers (2.5%), α-pinene (2.1%) and β-caryophyllene (1.2%). Several esters of isobutyric acid (4), monoterpene- (18), and sesquiterpene (15) hydrocarbons, oxides (6), monoterpene alcohols (10), esters (8) and aldehydes (4), (Z)-jasmone, citronellyl citronellate, citronellic acid, eugenol, and some aliphatic and alicyclic derivatives, were presented in trace amounts. On the polar column, further constituents were identified, including menthone, isomenthone, 4-vinylguiacol, and two heavy aliphatic acids: myristic and palmitic acids.

Published
2004
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20. Theory of the Salt Effect on Solvatochromic Shifts And Its Potential Application to the Determination of Ground-State and Excited-State Dipole Moments

Author

Mulder, W. H. and Parkanyi, C.

Abstract

The theory of solvatochromism based on a dielectric continuum description of the solvent and the classical Onsager cavity model is revisited and extended to include the effect of an added 1:1 salt. An expression is derived for the reaction field inside the solute cavity, which is applicable in the limit of low salt concentrations. Using this result, expressions are obtained for the shifts in the (0−0) absorption and fluorescence maxima on the basis of Marcus' approach to the calculation of the medium reorganization free energy in the ground state and excited (Franck−Condon) state of the solute molecule. The lifetime of the excited state is assumed to exceed the longest relaxation time characteristic of the medium. For the salt-free case, our equations differ markedly from several others reported in the literature dealing with the pure solvent effect, and the origin of the discrepancy is clarified. Finally, it is shown how the new equations can be used, in principle, to obtain estimates for the Onsager radius, polarizability, and dipole moments in the ground state and the lowest excited state of a solute molecule from a simple analysis of absorption and fluorescence data only, except in cases where the dipole moments are noncollinear. Completion of the analysis then requires an independent measurement of the ground-state dipole moment.

Published
2002
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