Browsing by Author "Agirtas, S"

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Liquefaction of Prangmites Australis by Supercritical Gas Extraction
(Elsevier Sci Ltd, 1999) Küçük, MM; Agirtas, S
Prangmites australis Mill was converted to liquid products by using organic solvents (methanol and ethanol) with catalyst (10% NaOH) and without catalyst in an autoclave at temperatures of 523 and 563 K. The liquid products were extracted by liquid-liquid ex-traction (benzene and diethyl ether). The yields from supercritical methanol and ethanol coversions were 38.7 and 53.6%, respectively, at 563 K. In the catalytic runs with methanol and ethanol the extracts were 44.2 and 57.6%, respectively, at 563 K. The yields from supercritical methanol were increased from 373 to 44.2% as the temperature was increased from 523 to 563 K in the catalytic run. (C) 1999 Elsevier Science Ltd. All rights reserved.
Spectral Study of the Supramolecular Assemblies Porphyrins-Phthalocyanines
(Elsevier, 2000) Agirtas, S; Ion, RM; Bekaroglu, O
The mixture between the solutions of one anionic porphyrin-5,10,15,20-tetra(p-sulfonato-phenyl-porphyrin (TSPP) and a charged-positive phthalocyanine-4,4 "-bis(4-trimethyl amino-ethyl sulphanyl) 4',4'''-di-amino-phthalocyanine dimethyl sulphate (Pc56) in polar solvent (DMSO), yielding to a well-defined supramolecular heterodimer (Pc/P) and a supra-molecular heterotrimer (Pc/P-2), are reported in this paper. The absorption spectra of such heterocomplexes are drastically changed with respect to the corresponding monomers, indicating the existence of a strong electrostatic interaction between these chromophores. The stoichiometry and formation constant of the heterocomplex are evaluated by means of Job method. The lifetimes for the first excited singlet states of the studied compounds were calculated and correlated with the singlet oxygen generation efficiency for the heterodimer and heterotrimer. (C) 2000 Elsevier Science S.A. All rights reserved.