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2005

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Articles 9751 - 9780 of 10378

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Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova Jan 2005

Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova

Turkish Journal of Chemistry

The catalytic effect of chromium(III) and chromium(VI) on the oxidation of sulfanilic acid by hydrogen peroxide was studied. The reaction was followed spectrophotometrically by measuring the absorbance of the reaction product at 360 nm. Under the optimum conditions 2 calibration graphs (for chromium(III) up to 100 ng mL^{-1}, and for chromium(VI) up to 200 ng mL^{-1}) were obtained, using the ``fixed time'' method with detection limits of 4.9 ng mL^{-1} and 3.8 ng mL^{-1}, respectively. The results suggest that at the reaction conditions chromium(VI) is reduced and chromium(III) is oxidized to an intermediate oxidation state and the catalytic action of …

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Proton Conduction In Pvpa --Benzimidazole Hybrid Electrolytes, Fatma Sevi̇l, Ayhan Bozkurt Jan 2005

Proton Conduction In Pvpa --Benzimidazole Hybrid Electrolytes, Fatma Sevi̇l, Ayhan Bozkurt

Turkish Journal of Chemistry

Proton conducting properties of benzimidazole (BnIm) doped poly(vinylphosphonic acid) (PVPA) were studied. The doping ratio, x, which is the number of moles of BnIm per mole of polymer repeat unit, varied from 0.5 to 2. The samples were characterized by FT-IR spectroscopy, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and impedance spectroscopy. The IR study indicates the protonation of heterocyclic units from the "free nitrogen" side. The proton conductivity and thermal stability of the blends increase with x. Maximum conductivity of PVPA x BnIm blends is approximately 10^{-3} S/cm at 150 °C.

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Synthesis Of Isomorphous Prototypic [Crfe_2o(Aco)_6(Tep)_3]Cl And [Crfe_2o(Aco)_6(Tmp)_3]Cl As Oxo-Centered Hetero Tri-Nuclear Carboxylate Complexes, Massoud Rafizadeh, Reza Tayebee, Vahid Amani Jan 2005

Synthesis Of Isomorphous Prototypic [Crfe_2o(Aco)_6(Tep)_3]Cl And [Crfe_2o(Aco)_6(Tmp)_3]Cl As Oxo-Centered Hetero Tri-Nuclear Carboxylate Complexes, Massoud Rafizadeh, Reza Tayebee, Vahid Amani

Turkish Journal of Chemistry

[CrFe_2O(AcO)_6(TEP)_3]Cl, (1), and [CrFe_2O(AcO)_6(TMP)_3]Cl, (2), were prepared by replacing 3 water molecules in the [CrFe_2O(AcO)_6(H_2O)_3]Cl complex with triethyl- and trimethyl-phosphates, respectively. FT-IR spectroscopy confirmed an oxo-centered, carboxylate-bridged, heteronuclear triangular structure for the title compounds. M_3O and MO_4 units adopted D_{3h} and D_{4h} local symmetry, respectively, and are surrounded by 6 bridging acetates with C_{2v} local symmetry.

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Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel Jan 2005

Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel

Turkish Journal of Chemistry

A more rapid and a versatile synthetic approach for the preparation of polyhedral silsesquioxanes (POSS) by hydrolytic condensation of organosilicon monomers in the presence of a Pt catalyst was studied. The structural properties of POSS molecules were determined by X-ray powder diffraction analysis, yielding a rhombohedral unit cell with a = 11,52796Å and \alpha = 94,9754° for octaaminopropyl-POSS, and a rhombohedral unit cell with a = 11,51421Å, \alpha = 96,7214° for octachloropropyl-POSS. The activation energies were found to be 64.8, and 89.1 kJ/mol for octaaminopropyl-POSS and octachloropropyl-POSS, respectively. The products were also characterized by Fourier transform infrared spectroscopy, ^1H and …

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Synthesis Of Novel Proponohydrazides And Their Hydrolysis Reactions, Mustafa Saçmaci, Emi̇n Saripinar, Yunus Akçamur Jan 2005

Synthesis Of Novel Proponohydrazides And Their Hydrolysis Reactions, Mustafa Saçmaci, Emi̇n Saripinar, Yunus Akçamur

Turkish Journal of Chemistry

4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-furandione 1 reacted with N-aryl substituted phenylhydrazones 3a-h via the p,p'-dimethoxydibenzoylketene intermediate 2 giving the proponohydrazide derivatives 5a-h. In addition, compounds 5a-h were converted into corresponding pyrazolone derivatives 7i,j by the reactions of hydrolysis in acidic solution. The structures of these new synthesized compounds were determined by ^{13}C NMR, ^1H NMR and IR spectroscopic data and elemental analysis.

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Studies On Mononuclear Chelates Derived From Substituted Schiff Base Ligands (Part 4): Synthesis And Characterization Of A New 5-Hydroxysalicyliden-P-Aminoacetophenoneoxime And Its Complexes With Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii), Erdal Canpolat, Mehmet Kaya Jan 2005

Studies On Mononuclear Chelates Derived From Substituted Schiff Base Ligands (Part 4): Synthesis And Characterization Of A New 5-Hydroxysalicyliden-P-Aminoacetophenoneoxime And Its Complexes With Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii), Erdal Canpolat, Mehmet Kaya

Turkish Journal of Chemistry

5-Hydroxysalicyliden-p-aminoacetophenoneoxime (LH) was synthesized starting from p-aminoacetophenoneoxime and 5-hydroxysalicylaldehyde. Complexes of this ligand with Co^{+2}, Ni^{+2}, Cu^{+2} and Zn^{+2} salts were prepared. With this ligand, complexes were synthesized using Co^{+2}, Ni^{+2}, Cu^{+2} and Zn^{+2} salt with a metal:ligand ratio of 1:2. Their structures were elucidated on the basis of elemental analyses, IR, ^1H- and ^{13}C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses.

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Synthesis Of Mannich Bases Of Some 2,5-Disubstituted 4-Thiazolidinones And Evaluation Of Their Antimicrobial Activities, Handan Altintaş, Öznur Ateş, Seher Bi̇rteksöz, Gülten Ötük, Meltem Uzun, Di̇lek Şanata Jan 2005

Synthesis Of Mannich Bases Of Some 2,5-Disubstituted 4-Thiazolidinones And Evaluation Of Their Antimicrobial Activities, Handan Altintaş, Öznur Ateş, Seher Bi̇rteksöz, Gülten Ötük, Meltem Uzun, Di̇lek Şanata

Turkish Journal of Chemistry

4-Carbethoxymethyl-2-[(\alpha -chloropropionyl/\alpha -bromobutyryl/\alpha-chloro-(\alpha-phenyl)acetyl)amino]thiazoles (2a-c) were synthesized by the reaction of 4-carbethoxymethyl-2-aminothiazole (1) with \alpha-chloropropionyl chloride, \alpha-bromobutyryl bromide and \alpha-chloro-\alpha -phenylacetyl chloride, respectively, which were then refluxed with ammonium thiocyanate to obtain 5-substituted 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones (3a-c). 3a-c were stirred with formaldehyde and various secondary amines to gain 15 novel compounds with the structure 5-substituted 5-(N,N-disubstituted aminomethyl)-2-[(4-carbethoxymethylthiazol-2-yl)imino]-4- thiazolidinones (4a-o). The antibacterial activities of the compounds against S. aureus ATCC 6538, S. epidermidis ATCC 12228, E. coli ATCC 8739, K. pneumoniae ATCC 4352, P. aeruginosa ATCC 1539, S. typhi, Sh. flexneri and Pr. mirabilis ATCC 14153 were tested using disk diffusion, while the antifungal …

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O-Galloyl Flavonoids From Geranium Pyrenaicum And Their In Vitro Antileishmanial Activity, Di̇lek Erci̇l, Maeki Kaloga, Oliver A. Radtke, M. Koray Sakar, Albrecht F. Kiderlen, Herbert Kolodziej Jan 2005

O-Galloyl Flavonoids From Geranium Pyrenaicum And Their In Vitro Antileishmanial Activity, Di̇lek Erci̇l, Maeki Kaloga, Oliver A. Radtke, M. Koray Sakar, Albrecht F. Kiderlen, Herbert Kolodziej

Turkish Journal of Chemistry

From the aerial parts of Geranium pyrenaicum Burm., a new flavonol glycoside, kaempferol 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (7), along with 6 known related glycosides [kaempferol 3-O-\beta-D-glucopyranoside (1), quercetin 3-O-\beta-D-glucopyranoside (2), quercetin 3-O-\beta-D-galactopyranoside (3), kaempferol 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (4), quercetin 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (5) and quercetin 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (6)] and the ellagitannins corilagin (8) and tellimagrandin I (9) were isolated. Their structures were established from spectroscopic studies (UV, FAB-MS, ^1H and ^{13}C-NMR, ^1H-^1H COSY, HETCOR, HMBC). Compounds 1-7 were evaluated for antileishmanial activity against a panel of Leishmania species (L. major, L. donovani and L. amazonensis), indicating appreciable in vitro activities (IC_{50} 4-27 nM) when compared with Pentostam (IC_{50} …

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Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan Jan 2005

Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan

Turkish Journal of Chemistry

The synthesis of a novel series of Mannich bases of 5-methyl-3-substituted piperazinomethyl-2-benzoxazolinones is described. The structures attributed to compounds 3c, 3d and 3f-3n were elucidated using IR and ^1H NMR spectroscopic techniques as well as elemental analysis. The compounds were examined for their in vivo anti-inflammatory and analgesic activities in 2 different bioassays, namely, carrageenan-induced hind paw edema and p-benzoquinone-induced abdominal constriction tests in mice, respectively. In addition, the ulcerogenic effects of the compounds were determined. Among the derivatives tested the most promising results were obtained for the compounds bearing electron-withdrawing substituents (F, Cl, COCH_3) in the para position of …

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Cover And Contents Jan 2005

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

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Generating Estimates Of Classification Confidence For A Case-Based Spam Filter, Sarah Jane Delany, Padraig Cunningham, Donal Coyle, Anton Zamolotskikh Jan 2005

Generating Estimates Of Classification Confidence For A Case-Based Spam Filter, Sarah Jane Delany, Padraig Cunningham, Donal Coyle, Anton Zamolotskikh

Conference papers

Producing estimates of classification confidence is surprisingly difficult. One might expect that classifiers that can produce numeric classification scores (e.g. k-Nearest Neighbour, Na¨ıve Bayes or Support Vector Machines) could readily produce confidence estimates based on thresholds. In fact, this proves not to be the case, probably because these are not probabilistic classifiers in the strict sense. The numeric scores coming from k-Nearest Neighbour, Na¨ıve Bayes and Support Vector Machine classifiers are not well correlated with classification confidence. In this paper we describe a case-based spam filtering application that would benefit significantly from an ability to attach confidence predictions to positive …

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Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol Jan 2005

Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol

Turkish Journal of Chemistry

The synthesis of 2-[2-(3,4,5-trimethoxybenzoyloxy)ethyl]pyrrolidine hydrochloride was performed using 2-(2-hydroxyethyl)pyrrolidine as a starting material. Before the O-acylation reaction with 3,4,5-trimethoxybenzoyl chloride, the amino group was protected using benzyl chlorocarbonate. The removal of the blocking group was carried out in modified conditions, avoiding the alcoholysis of the ester bond. The final product was separated from its structural isomer by precipitation as its hydrochloride salt. Some steps of the synthesis were controlled by GC-MS. The identification of the respective compounds was performed by mass spectra analyses and confirmed by ^1H NMR, ^{13}C NMR, IR and elemental analyses.

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Cover And Contents Jan 2005

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

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Cover And Contents Jan 2005

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

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Synthesis And Characterization Of New Triheterocyclic Compounds Consisting Of 1,2,4-Triazol-3-One, 1,3,4-Thiadiazole And 1,3,4-Oxadiazole Rings, Nesli̇han Demi̇rbaş Jan 2005

Synthesis And Characterization Of New Triheterocyclic Compounds Consisting Of 1,2,4-Triazol-3-One, 1,3,4-Thiadiazole And 1,3,4-Oxadiazole Rings, Nesli̇han Demi̇rbaş

Turkish Journal of Chemistry

A series of acetic acid derivatives (2a-c) was synthesized by the condensation of compounds 1a-c with chloroacetic acid. The treatment of carboxylic acid derivatives with thiosemicarbazide in phosphorus oxychloride and subsequent diazotation of the products (3a-c) afforded 5-alkyl-2-[(5-chloro-1,3,4-thiadiazol-2-yl)methyl]- 2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (4a-c). The treatment of compounds 4a-c with thiourea produced 5-alkyl-2-[(5-mercapto-1,3,4- thiadiazol-2-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (5a-c). Subsequently, compounds 5a-c were converted to acid hydrazides by treatment with hydrazine hydrate after esterification (7a-e). Moreover, the reaction of compounds 7a-c with carbon disulfite in the presence of KOH afforded 5-alkyl-2-[(5-\{[(5- mercapto-1,3,4-oxadiazol-2-yl)methyl]thio\}-1,3,4-thiadiazol-2-yl)methyl]- 2,4-dihydro-3H-1,2,4-triazol-3-ones (8a-c).

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Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen Jan 2005

Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen

Turkish Journal of Chemistry

From the roots of Salvia blepharochlaena Hedge and Hub. Mor. 4 triterpenoids, 4 steroids, 6 diterpenoids, and an aromatic ester were isolated. The structures of these compounds were established by spectroscopic methods. Formosanolide was isolated for the first time from the genus Salvia.

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Cover And Contents Jan 2005

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

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Effective Knowledge Management (Km) Strategy Within A Business Organization, Brian L. Roeder Jan 2005

Effective Knowledge Management (Km) Strategy Within A Business Organization, Brian L. Roeder

Theses

A cohesive Knowledge Management (KM) strategy is found at the cornerstone of every successful business enterprise's overall business strategy. The full benefit of this strategy can only be achieved through a dynamic, technology-enabled framework that encourages best and better practices to capture the outputs of human innovation and creative knowledge. Competitive pressures and technological convergence, most prevalent in high technology business sectors, have demonstrated the critical need for an information strategy that can harness and discern the continual amass of intellectual property. The continual accumulation of information and knowledge critical to the sustained viability of many business organizations, presents significant …

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Examination Of Some Organic Explosives By Ion Mobility Spectrometry (Ims), Hülya Koyuncu, Ertan Seven, Ayla Çalimli Jan 2005

Examination Of Some Organic Explosives By Ion Mobility Spectrometry (Ims), Hülya Koyuncu, Ertan Seven, Ayla Çalimli

Turkish Journal of Chemistry

The increase in terrorist activities committed using explosives in recent years has generated the need for improved analytical methods that can accurately and quickly identify explosives and their residues. In this study such an analytical method is evaluated. In the first phase of the study, standard solutions and a standard mixture solution of TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitro-1,3,5-triazocyclohexane), PETN (pentaerythritoltetranitrate) and TETRYL (2,4,6-trinitrophenylmethylnitramine) were examined using ion mobility spectrometry (IMS). In the second phase, qualitative analysis of a real explosion residue was carried out and the explosive material used in the bomb was identified by analysing the acetone extract. In the …

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The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu Jan 2005

The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu

Turkish Journal of Chemistry

The effect of metal loading on structural properties and CO oxidation activity of coprecipitated Co/Al_2O_3 catalysts was investigated. The results indicated the participation of cobalt in the Co-Al skeleton for all coprecipitated samples. Environmental-SEM-EDXS studies showed that at loadings higher than ca. 15 wt.-%, cobalt formed layer-by-layer clusters on the surface; 16.8 wt.-% Co/Al_2O_3 displayed the highest activity and stability in CO oxidation.

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Mechanism And Kinetics Of Copper(Ii) Transport Through A Liquid Membrane Containing A Dithiophosphonate Derivative As Carrier, H. Korkmaz Alpoğuz, Ahmet Kaya, Mehmet Karakuş Jan 2005

Mechanism And Kinetics Of Copper(Ii) Transport Through A Liquid Membrane Containing A Dithiophosphonate Derivative As Carrier, H. Korkmaz Alpoğuz, Ahmet Kaya, Mehmet Karakuş

Turkish Journal of Chemistry

The transport of Cu(II) ions from an aqueous solution into an aqueous receiving solution through a bulk liquid membrane containing a dithiophosphonate derivative (1) as a carrier was examined. The kinetic parameters were analyzed assuming 2 consecutive, irreversible first-order reactions. The influence of temperature and stirring rate on the kinetic parameters (k_1, k_2, R_m^{max}, t_{max}, J_d^{max} and J_a^{max}) was also investigated. The membrane entrance rate, k_1, and the membrane exit rate, k_2, increased with increasing temperature and stirring rate. For the maximum membrane exit flux, J_a^{max}, the activation energy was determined from the slope of the linear Arrhenius relationship to …

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Phlinoside F, A New Phenylethanoid Glycoside From Phlomis Angustissima, Funda Nuray Yalçin, Tayfun Ersöz, Erdal Bedi̇r, Sevser Şahpaz, François Bailleul, Ikhlas A. Khan, Ali̇ Arslan Dönmez, İhsan Çaliş Jan 2005

Phlinoside F, A New Phenylethanoid Glycoside From Phlomis Angustissima, Funda Nuray Yalçin, Tayfun Ersöz, Erdal Bedi̇r, Sevser Şahpaz, François Bailleul, Ikhlas A. Khan, Ali̇ Arslan Dönmez, İhsan Çaliş

Turkish Journal of Chemistry

From the overground parts of Phlomis angustissima, a new phenylethanoid triglycoside, \beta-(3-hydroxy,4-methoxyphenyl)ethyl- O-[\beta -xylopyranosyl(1 \to 2)-\alpha -rhamnopyranosyl-(1 \to 3)] -O-4-O-feruloyl-\beta -glucopyranoside, named phlinoside F, was isolated along with the known compounds alyssonoside, samioside, lamiide, auroside, naringenin, and syringaresinol-4-O-\beta -D-glucopyranoside. The structure of the new glycoside was elucidated by spectroscopic methods.

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New Alkoxyzinc Salts Mediated Chemoselective Transesterification Reactions, Necdet Coşkun, Mustafa Er Jan 2005

New Alkoxyzinc Salts Mediated Chemoselective Transesterification Reactions, Necdet Coşkun, Mustafa Er

Turkish Journal of Chemistry

A new chemoselective method for the transesterification of alkyl esters in the presence of in situ formed alkoxyzinc salts was developed. Electron-rich esters are less reactive than electron poor ones and this is the basis for the chemoselectivity of the reaction. Suggested mechanisms of the transesterification reactions are discussed.

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The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan Jan 2005

The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan

Turkish Journal of Chemistry

Our aim was to improve the relatively poor adsorption characteristics of natural pyrophyllite and those of TiO_m and Ti(OR)_x(OH)_y(O)_z obtained from titanium tetraisopropoxide (TTIP) by the sol-gel process. For this purpose, the surfaces of the above-mentioned adsorbents were coated with a surface modifier by dipping them in 1% and 50% (w/w) solutions of N-(2-aminoethyl)-3- aminopropyltrimethoxysilane (DIAMO) in methanol. Realization of the coating processes was checked by FT-IR and SEM analyses. FT-IR analyses of the coated powders heat treated at 110 °C showed that condensation took place between OH groups of prehydrolyzed silane molecules and hydroxyl groups and/or oxygen atoms on …

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Selective Oxidation Of Thiols To Disulfides Catalyzed By Iron(Iii) -- Tetra Phenyl Porphyrin Using Urea-Hydrogen Peroxide As Oxidizing Reagent, Bahador Karimi, Morteza Montazerozohori, Majid Moghadam, Mohammad Hosein Habibi, Khodabakhsh Niknam Jan 2005

Selective Oxidation Of Thiols To Disulfides Catalyzed By Iron(Iii) -- Tetra Phenyl Porphyrin Using Urea-Hydrogen Peroxide As Oxidizing Reagent, Bahador Karimi, Morteza Montazerozohori, Majid Moghadam, Mohammad Hosein Habibi, Khodabakhsh Niknam

Turkish Journal of Chemistry

Oxidation of thiols to disulfides catalyzed by iron(III) -- tetra phenyl prophyrin Fe (TPP)Cl was investigated using urea-hydrogen peroxide adduct (UHP) as an oxidant in methanol as a solvent.

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Miscibility Of Methylmethacrylate-Co-Methacrylic Acid Polymer With Magnesium, Zinc, And Manganese Sulfonated Polystyrene Ionomers, Cemi̇l Alkan, Nebahat Yurtseven, Leyla Aras Jan 2005

Miscibility Of Methylmethacrylate-Co-Methacrylic Acid Polymer With Magnesium, Zinc, And Manganese Sulfonated Polystyrene Ionomers, Cemi̇l Alkan, Nebahat Yurtseven, Leyla Aras

Turkish Journal of Chemistry

The miscibility of methyl methacrylate-co-methacrylic acid polymer (MMA-MAA) with metal neutralized sulfonated polystyrene ionomers was investigated by viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared radiation spectroscopy (FTIR) techniques. Polystyrene (PS) was sulfonated by acetic anhydride and sulfuric acid and the sulfonation degree was found to be 2.6 mole percent, and 2.6 mole percent sulfonated polystyrene was neutralized by Mg, Zn, and Mn salts. The miscibility behavior of the blends of MMA-MAA with Mg neutralized 2.6 mole% sulfonated polystyrene (2.6MgSPS), Mn neutralized 2.6mole% sulfonated polystyrene (2.6MnSPS), and Zn neutralized 2.6 mole% sulfonated polystyrene (2.6ZnSPS) was investigated by dilute solution …

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Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r Jan 2005

Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r

Turkish Journal of Chemistry

Three known triterpene glycosides were isolated from the MeOH extract of dried and powdered seeds of Nigella sativa. The structures of the compounds were established as 3-O-[\beta-D-xylopyranosyl- (1 \to 3)-\alpha-L-rhamnopyranosyl-(1 \to 2)-\alpha -L-arabinopyranosyl]- 28-O-[\alpha-L-rhamnopyranosyl-(1 \to 4)-\beta-D-glucopyranosyl-(1 \to 6)- \beta-D-glucopyranosyl]-hederagenin (1), 3-O-[\alpha -L-rhamnopyranosyl- (1 \to 2)-\alpha-L-arabinopyranosyl]-28-O-[\alpha -L-rhamnopyranosyl-(1 \to 4)- \beta-D-glucopyranosyl-(1\to 6)-\beta-D-glucopyranosyl]-hederagenin (2), and 3-O-[\beta-D-xylopyranosyl- (1\to 3)-\alpha-L-rhamnopyranosyl-(1\to 2)-\alpha- L-arabinopyranosyl]-hederagenin (3) by means of chemical and spectral methods. Compound 2 was isolated for the first time from the genus Nigella.

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Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel Jan 2005

Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel

Turkish Journal of Chemistry

The manganese(III) acetate mediated radical cyclization of dimedone 1a, 2,4-pentanedione 1b, ethyl acetoacetate 1c, 1,3-cyclohexanedione 1d and 5-phenyl-1,3-cyclohexanedione 1e with 1,1-diphenyl-1-butene 2a afforded 4,5-dihydrofurans (3c, 3e) and tetrahydrobenzofurans (3a, 3g, 3h) in good yields (55% - 77%). Additionally, the reactions of trifluoromethyl-group containing 1,3-dicarbonyls, 4,4,4-trifluoro-1-phenylbutane-1,3-dione 1f and 4,4,4-trifluoro-1-thien-2ylbutane-1,3-dione 1g with 2a 3-trifluoroacetyl-4,5-dihydrofurans gave in 74% and 78% yields, respectively. Treatment of 1a, 1b and 1c with 1,2-diphenyl-1-pentene 2a resulted in the formation of tetrahydrobenzofuran 3b and 4,5-dihydrofurans 3d and 3f in lower yields.

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Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n Jan 2005

Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n

Turkish Journal of Chemistry

The equilibrium sorption isotherms of 3 reactive dyes (C. I. Reactive Yellow 84, C. I. Reactive Red 141, C. I. Reactive Blue 160) and their binary mixtures adsorbed on prewetted wool fiber were investigated. The kinetic studies were carried out at pH \le 7 and 80 °C in dye solutions containing 20 g/L NaCl. It was reported that binary mixtures of these reactive dyes have lower sorption values than the dyes alone, at the same dye concentration, pH and temperature. The isotherms obtained are Langmuir type. The rate parameters of adsorption kinetics decrease with increasing dye concentration.

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Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz Jan 2005

Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz

Turkish Journal of Chemistry

A spectrophotometric study concerning the interaction between A15C5 as n-donor and TCNE, DDQ, TCNQ and bromanil as \pi -acceptor was been performed in chloroform at 25 °C. The results of TCNE indicate the formation of a 1:1 charge-transfer complex through a nonequilibrium reaction. In the case of DDQ, the formation of 1:2 (A15C5/DDQ) and 1:1 charge-transfer complexes through equilibrium and nonequilibrium reactions is confirmed. The formation constant of the equilibrium step was evaluated from the computer fitting of the absorbance-mole ratio data as logK_f = 5.14 \pm 0.09. The [A15C5^+ (DDQ)_2^- ] and [A15C5^+DDQ^- ] are suggested as the possible …

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