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Articles 31 - 48 of 48
Full-Text Articles in Chemistry
A Study On N-Hydroxyamide Ethoxycarbonylhydrazones, A. Aykut İki̇zler, Ahmet Demi̇rbaş, Rza Abbasoğlu
A Study On N-Hydroxyamide Ethoxycarbonylhydrazones, A. Aykut İki̇zler, Ahmet Demi̇rbaş, Rza Abbasoğlu
Turkish Journal of Chemistry
The structures and electronic properties of N-hydroxyamide ethoxycarbonylhydrazones were investigated by a quantum-chemical method AMl. The total energies, heats of formation, dipol moments, ionization potentials, proton affinities and energies of frontier molecular orbitals (E_{HOMO} and E_{LUMO}) were calculated and discussed. The stabilities of the tautomeric forms and of E and Z isomers for these compounds were determined. The complex forming ability of these compounds with metal cations was also studied. The geometry and electronic properties of the complexes formed by N-hydroxyacetamide ethoxycarbonylhydrazone with Ni^{2+} and Cu^{2+} were investigated using ZINDO/1 semiempirical method. Moreover, these complexes were synthesized and identified.
The Measurement Of Surface Areas Of Some Silicates By Solution Adsorption, Oğuz İnel, Fatma Tümsek
The Measurement Of Surface Areas Of Some Silicates By Solution Adsorption, Oğuz İnel, Fatma Tümsek
Turkish Journal of Chemistry
In this study, the adsorption from solution technique was used for the determination of surface areas of some silicate samples (bentonite, sepiolite, zeolitic tuff and kaolin). Methylene blue (MB), orthophenanthroline (OP) and p-nitrophenol (PNP) were selected as solutes. The adsorption data was found to conform with the Langmuir equation within the concentration range studied, and Langmuir constants were determined for each of the samples. The surface area values obtained were compared with those determined by nitrogen adsorption. Also the results were discussed with respect to the cation exchange capacities of the samples. The specific surface area values of the samples …
Synthesis And Reactivity Of Some Mannich Bases. Vi. New Arylamine Mannich Bases Derived From 2-Hydroxy-5-Methylacetophenone, Gheorghe Roman, Diana Nanu, Eugenia Comanita, Bogdan Comanita
Synthesis And Reactivity Of Some Mannich Bases. Vi. New Arylamine Mannich Bases Derived From 2-Hydroxy-5-Methylacetophenone, Gheorghe Roman, Diana Nanu, Eugenia Comanita, Bogdan Comanita
Turkish Journal of Chemistry
The amine exchange reaction has been applied for obtaining a new series of arylamine Mannich bases from variously substituted aromatic amines and 3-(dimethylamino)-1-(2'-hydroxy-5'-methylphenyl) propan-1-one. The structures of the newly synthesised Mannich bases have been investigated by IR, ^1H- and ^{13}C-NMR and shown to be in good agreement with the proposed ones.
Preparation Of Optically Active Amino Acid Derivatives Of Some Methylated 5-Amino-Azaheterocycles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus, Shazia Munir
Preparation Of Optically Active Amino Acid Derivatives Of Some Methylated 5-Amino-Azaheterocycles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus, Shazia Munir
Turkish Journal of Chemistry
The present paper describes the reduction of 1-methyl-5-nitro-benzimidazoles ({\bf 1A, 2A}) and 1,3-dimethyl-2H-5-nitro-benzimidazol-2-one ({\bf 3}) to 5-aminobenzimidazoles ({\bf 4A, 5A}) and 1,3-dimethyl-2H-5-amino-benzimidazol-2-one ({\bf 6}) respectively with hydrazine hydrate in absolute ethanol in the presence of graphite. Compounds {\bf 5A} and {\bf 6} were converted to 2-ethyl-5-(phthaloyl-L-phenylalanyl)amino-1-methylbenzimidazole ({\bf 7}) and 1,3-dimethyl-5-(phthaloyl-L-phenylalanyl)aminobenzimidazol-2-one ({\bf 8}). Characterization of the synthesized compounds was done with the help of mass spectrometry and ^1H NMR spectroscopic studies. Optical activity of the amino acid derivatives {\bf 7} and {\bf 8} was also recorded.
Polarographic Determination Of Fluvoxamine Maleate In Tablets, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Sidika Sungur, Şule Aycan
Polarographic Determination Of Fluvoxamine Maleate In Tablets, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Sidika Sungur, Şule Aycan
Turkish Journal of Chemistry
The differential pulse polarographic (DPP) method was developed for the determination of fluvoxamine maleate (I). At pH = 3. 7, (I) give a peak at - 0. 73 V in aqueous solution. The developed method was applied to the assay of the drug substance in commercial tablet formulations. The results were statistically compared with those obtained by reference methods (HPLC and direct current polarographic method) using t- and F- tests at 95 % confidence level.
Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz
Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz
Turkish Journal of Chemistry
The construction and performance characteristics of ion-selective membrane electrodes for a newly found phenylpiperazine antidepressant, Nefazodone (NFN), based on its ion-pair complexes with phosphotungstate (PT), tetraphenylborate (TPB), tungstosilicate (TS) and reineckate (RN) in a poly(vinyl chloride) (PVC) matrix are described. The best ion-selective electrode for determination of NFN contains NFN-PT as the active material. This electrode exhibits a Nernstian response (62.6 ± 0.4 mV per decade) in the range 1.5 x 10$^{-5}$ to 1.0 x 10^{-2} M NFN.HCl in solutions. The selectivity of this electrode to NFN in the presence of a number of sugar molecules, cations and drugs is …
X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep
X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep
Turkish Journal of Chemistry
In this study, CaBPO_5 was synthesized by different solid state reactions than reported before and its X-ray powder diffraction and IR data were reported. In one of these solid state reactions BPO_4 was used as a phosphating agent. The examination of the X-ray powder diffraction data showed that this compound crystallized in a hexagonal system and the refined unit cell parameters were a = 6.684, c = 6.616(2) \AA, with Z=3 as reported before. From the observed reflections, the space group was determined as P3_121, and its density was found to be 3.15 g/cc. The X-ray powder diffraction and IR …
All Solid-State Contact Lead(Ii) Ion-Selective Pvc Membrane Electrode Using Dimethylene Bis(4-Methylpiperidinedithiocarbamate) Neutral Ionophore, İbrahi̇m Işildak
All Solid-State Contact Lead(Ii) Ion-Selective Pvc Membrane Electrode Using Dimethylene Bis(4-Methylpiperidinedithiocarbamate) Neutral Ionophore, İbrahi̇m Işildak
Turkish Journal of Chemistry
All solid-state contact PVC membrane electrodes for lead(II) ion were developed by using dimethylene bis(4-methylpiperidinedithiocarbamate) as neutral carrier and nitrophenyloctyl ether or dioctylsebacate as plasticizers. Response properties of the all solid-state contact PVC membrane electrode prepared with nitrophenyloctyl ether were better than those of the membrane electrode prepared with dioctylsebacate. The nitrophenyloctyl ether plasticized the all solid-state contact PVC membrane electrode and exhibited a good linear response of 30 mV/decade for lead(II) ion within the concentration ranges \( 0.1-5\times10^{-6} \) mol dm\( ^{-3} \) lead(II) nitrate, good selectivity over alkali, alkali-earth and transition metal ions including copper(II) ion by a …
High-Performance Liquid Chromatographic Determination Of Oxytetracycline Residue In Cured Meat Products, Hami̇de Z. Şenyuva, Tuncel Özden, Deni̇z Yurtsever Sarica
High-Performance Liquid Chromatographic Determination Of Oxytetracycline Residue In Cured Meat Products, Hami̇de Z. Şenyuva, Tuncel Özden, Deni̇z Yurtsever Sarica
Turkish Journal of Chemistry
The development of a sensitive automated method for residue control of oxytetracycline (OTC) in cured meat (soudjouk) is described. The principle steps involve the extraction of OTC from cured meat in the presence of citric acid with nitric acid, methanol and de-ionized water, and then the determination by HPLC. In HPLC, Hypersil BDC C18 column was used and OTC was separated at 24 ^{o}C using a mobile phase of H_2O (pH=2.10 with H_2SO_4): ACN (85:15, v/v) at a flow rate of 1.5 ml/min. A variable wavelength detector was set at 360 nm. The detection limit of the method was calculated …
Adsorption Of Some Heavy Metal Ions From Aqueous Solution By Activated Carbon And Comparison Of Percent Adsorption Results Of Activated Carbon With Those Of Some Other Adsorbents, İlhan Uzun, Fuat Güzel
Adsorption Of Some Heavy Metal Ions From Aqueous Solution By Activated Carbon And Comparison Of Percent Adsorption Results Of Activated Carbon With Those Of Some Other Adsorbents, İlhan Uzun, Fuat Güzel
Turkish Journal of Chemistry
In this study, removal of some heavy metals ions (Mn^{2+}, Fe^{2+}, Ni^{2+} and Cu^{2+}) from aqueous solution by adsorption was investigated. For this purpose, high-grade MnSO_4.H_2O, FeSO_4.7H_2O, NiSO_4.7H_2O and CuSO_4.5H_2O were used as heavy metal samples. The commercial activated carbon (Merck 2514), chitosan and agar were used as adsorbents. The pH of each solution was not controlled. This is because the net interaction between the adsorbent and the heavy metal could be disturbed by the buffer solution. Therefore, all experiments were carried out in a pH range from 5.3 to 5.5. The equilibrium adsorption contact times were determined for M …
Photochemical Processes And Accumulation Of Solar Energy In Oil Luminophors, A. P. Mamedov, M. I. Rustamov, R. A. Dzhafarova, Ch. K. Salmanova
Photochemical Processes And Accumulation Of Solar Energy In Oil Luminophors, A. P. Mamedov, M. I. Rustamov, R. A. Dzhafarova, Ch. K. Salmanova
Turkish Journal of Chemistry
Using the methods of absorption spectroscopy, luminescence and EPR there has been studied the mechanism of solar energy accumulation by high boiling products of oil refining and by luminophors prepared on their basis within wide temperature range (77-550 K). The photochemical processes with participation of all main components of oil products and luminophors have been considered. The mechanisms of accumulation of solar energy of the studied products and luminophors have been considered. The mechanism of accumulation of solar energy of the studied products prior and above their pour points have been found to differ significantly. The light energy accumulation and …
Swelling Behavior Of Acrylamide-2-Hydroxyethyl Methacrylate Hydrogels, Belma Işik Yürüksoy
Swelling Behavior Of Acrylamide-2-Hydroxyethyl Methacrylate Hydrogels, Belma Işik Yürüksoy
Turkish Journal of Chemistry
In this study, hydrogels of poly(acrylamide-co-2-hydroxyethyl methacrylate) having different properties were prepared by a redox polymerization method. Poly(ethylene glycol), PEG 4000 was included in the polymerization recipe to increase the microporosity of the resultant polymeric structures. AAm/HEMA hydrogels with different properties were obtained by changing initial AAm/HEMA mole ratio, total monomer, PEG 4000 and crosslinker concentrations.
Solvent Extraction Of Fe^{3+} Cation By Diazo-Coupling Calix[4]Arenes, Hasaletti̇n Deli̇göz, Emi̇n Erdem, Hasan Kocaokutgen
Solvent Extraction Of Fe^{3+} Cation By Diazo-Coupling Calix[4]Arenes, Hasaletti̇n Deli̇göz, Emi̇n Erdem, Hasan Kocaokutgen
Turkish Journal of Chemistry
The solvent extraction of Fe^{3+} cations from the aqueous to the organic (chloroform) phase was carried out using p-tert-butyl calix[4]arene(\underline{1}), calix[4]arene(\underline{2}), diazo-coupling calix[4]arenes [p-(4-n-butyl-phenylazo)calix[4]arene (\underline{3}), p-(4-phenylazophenylazo)calix[4]arene(\underline{4}), p-(4-acetanilidazo)calix[4]arene(\underline{5}), p-(N'-2-thyazol-2ylsulphanylazo)calix[4]arene(\underline{6}) and p-(2-thyazolazo)calix[4]arene(\underline{8}) and the derivatives of phenol [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(\underline{8}) (Bromo-PADAP) and 2-hydroxy-5-methyl\-phenylazonapthol(\underline{9}) (HMPAN)]. It was found that the compounds (\underline{1}-\underline{9}) showed the highest extractability toward Fe^{3+} at pH 4.5-5.4 Compound \underline{5} shows strong binding ability to Fe^{3+} ion. Based on the method of continuous variation, calixarene \underline{5} formed a 1:1 complex with Fe^{3+} ion.
Kinetics And Thermodynamics Of Oil Extraction From Sun Ower Seeds In The Presence Of Aqueous Acidic, Hüseyi̇n Topallar, Ümi̇t Geçgel
Kinetics And Thermodynamics Of Oil Extraction From Sun Ower Seeds In The Presence Of Aqueous Acidic, Hüseyi̇n Topallar, Ümi̇t Geçgel
Turkish Journal of Chemistry
Oil extraction was performed in aqueous HCl, H_2SO_4 and H_3PO_4 solutions with n-hexane (C_6H_{14}) at 30, 40, 50 and 60 ^oC using 10 gr of sunflower seeds over 1 h with 10-min. sampling intervals. The optimum acid concentration was wt. 10% for each acid, and the highest oil yield was obtained in the extraction procedure with n-hexane containing H_2SO_4. The extraction process was observed with regard to the percent oil yield versus time, and the reaction order was found to be first-order kinetics by the differential method. The activation energy for the oil extraction kinetics of sunflower seeds with 10% …
Synthesis Of A New Dihydropyridine Derivative Containing A Known Vasodilator Khellin, Gülgün Ayhan Kilcigi̇l, Meral Tunçbi̇lek, Rahmi̇ye Ertan, Kevser Erol, Engi̇n Yildirim
Synthesis Of A New Dihydropyridine Derivative Containing A Known Vasodilator Khellin, Gülgün Ayhan Kilcigi̇l, Meral Tunçbi̇lek, Rahmi̇ye Ertan, Kevser Erol, Engi̇n Yildirim
Turkish Journal of Chemistry
The synthesis and spasmolytic activity of a novel dihydropyridine derivative which contains a vasodilator furanochromone khellin at the 4^{th}$ position of the dihydropyridine ring via the Hantzsch method from khellin-2-carboxaldehyde is described.
The Effect Of Acetone On Calomel Formation On A Mercury Film Electrode Surface In Chloride Medium, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural
The Effect Of Acetone On Calomel Formation On A Mercury Film Electrode Surface In Chloride Medium, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural
Turkish Journal of Chemistry
In the presence of chloride ions, calomel formation takes place on the mercury thin film electrodes under open-circuit conditions, which leads to high base currents and erratic performance in ASV meas- urements. This study describes the effect of chloride concentration on the calomel formation on the surface by following the cathodic peak on the anodic scan. The effect of acetone on the surface reaction and baseline stability was studied. Application of the method with a sea water sample is also given.
The Rate Of Grafting And Some Kinetic Parameters Of The Graft Copolymerization Of Methacrylic Acid On Poly (Ethylene Terephthalate) Fibers With Azobisisobutyronitrile, Meltem Çeli̇k, Mehmet Saçak
The Rate Of Grafting And Some Kinetic Parameters Of The Graft Copolymerization Of Methacrylic Acid On Poly (Ethylene Terephthalate) Fibers With Azobisisobutyronitrile, Meltem Çeli̇k, Mehmet Saçak
Turkish Journal of Chemistry
In this study the rate of grafting and some kinetic parameters of the graft copolymerization of methacrylic acid on poly(ethylene terephthalate) fibers with azobisisobutyronitrile was investigated. The rate of grafting was found to be proportional to the 0.94 and 1.22 powers of initiator and monomer concentrations, respectively. By carrying out the graft copolymerization reaction at four different temperatures ranging from 70 ^oC to 90 ^oC, the overall rate activation energy of the reaction was found to be 130.4 kJ/mol. The overall rate constants were also calculated.
Synthetic Metal Alloys: Preparation Of Polyaniline/Polypyrrole Alloys In Protic Medium, Fati̇h Köleli̇, Meltem Düdükcü, Yasemi̇n Arslan
Synthetic Metal Alloys: Preparation Of Polyaniline/Polypyrrole Alloys In Protic Medium, Fati̇h Köleli̇, Meltem Düdükcü, Yasemi̇n Arslan
Turkish Journal of Chemistry
Pyrrole and aniline solutions were mixed in different ratios and oxidized under anodic conditions on Pt surface in protic medium. The electrocopolymerization and electrochemical properties of these alloys were investigated. Current-potential diagrams of polyaniline (PA), polypyrrole (PP) and the resulting alloys were recorded and their electrochemical characterizations were identified. In-situ resistance measurements of synthesized alloys were carried out with a home-made apparatus. Conductivity of alloys showed changes depending on applied potential as intrinsic polymers. The electrochemical behaviour of homopolymers and alloys was studied at different temperatures.