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Articles 2431 - 2460 of 2720
Full-Text Articles in Chemistry
Modification Of Poly(Maleic Anhydride-Co-Styrene) With Hydroxyl Containing Compounds, Oya Gali̇oğlu Atici, Ahmet Akar, Roshan Rahimian
Modification Of Poly(Maleic Anhydride-Co-Styrene) With Hydroxyl Containing Compounds, Oya Gali̇oğlu Atici, Ahmet Akar, Roshan Rahimian
Turkish Journal of Chemistry
Soluble and cross-linked poly(maleic anhydride-co-styrene) copolymers were reacted with hydroxyl containing compounds such as salicylic acid, 2-phenyl ethanol, eugenol and paracetamole in acetone or dioxane solution at 50-80°C. The hydrolytic and controlled release behavior of the copolymers containing these compounds in water was studied. The extent of hydrolysis was found to be affected by the type of polymer support as well as time, temperature and the type of supported compound.
Secondary Amine Mediated Ring-Opening Of Tetrahydroimidazo[1,5- B ][1,2,4]Oxadiazol-2(1 H )-Ones, Necdet Coşkun
Secondary Amine Mediated Ring-Opening Of Tetrahydroimidazo[1,5- B ][1,2,4]Oxadiazol-2(1 H )-Ones, Necdet Coşkun
Turkish Journal of Chemistry
5,6,7,7a-Tetrahydroimidazo [1,5- b ][1,2,4]oxadiazol-2(1 H )-ones 1a-g converted to imidazoles in the presence of secondary amines. cis-Imidazooxadiazolones 1d-g gave the imidazoles 4d-g when treated with secondary amines, while the treatment of these compounds with tertiary amines afforded imidazoline 3-oxides 5d-g. In case of 1a-c, where R^1 is a hydrogen, tertiary amines induced elimination to give imidazoles 4a-c. In the case of 1a-c, probable trans elimination caused by triethylamine and pyridine and in the case of 1d-f, a concerted double cis elimination mediated by secondary amines is discussed.
Towards The Asymmetric Synthesis Of Ascochlorin, Özdemi̇r Doğan, Wolfgang Oppolzer
Towards The Asymmetric Synthesis Of Ascochlorin, Özdemi̇r Doğan, Wolfgang Oppolzer
Turkish Journal of Chemistry
A synthetic approach is described to the asymmetric synthesis of ascochlorin (1), an antiviral antibiotic, based on the construction of a sesquiterpene unit via asymmetric Diels-Alder reaction of tigloyl sultam 4 & butadiene, and the introduction of the aromatic side chain (C9-C12 unit) by employing cuprate chemistry.
Adsorption Of Non-Ionic Surface Active Agent On Fine Coal And Lignite, Zeki̇ Aktaş
Adsorption Of Non-Ionic Surface Active Agent On Fine Coal And Lignite, Zeki̇ Aktaş
Turkish Journal of Chemistry
The adsorption of Triton X-100 in aqueous solution on the less than 53 \\mum size fractions of Tunçbilek lignite and Zonguldak bituminous coal was studied. The adsorption isotherms were formed for 5, 30 and 1,440 (equilibrium) minutes. The isotherms were evaluated using both Langmuir and Freundlich adsorption equations. Concentrations of the reagent in the monolayer after equilibrium adsorption were determined to be 8.17 and 7.27 \\muM/g coal for the lignite and bituminous coal using the Langmuir adsorption equation. The specific adsorption capacity per unit area of Zonguldak bituminous coal was 5.3 times higher than that of Tunçbilek lignite. The adsorption …
Electrooxidation Of Methanol And Formic Acid On Platinum Dispersed Polypyrrole Electrodes, İpek Beceri̇k, Fi̇gen Kadirgan
Electrooxidation Of Methanol And Formic Acid On Platinum Dispersed Polypyrrole Electrodes, İpek Beceri̇k, Fi̇gen Kadirgan
Turkish Journal of Chemistry
The present study was performed in order to investigate the electrocatalytic properties of platinum incorporated polypyrrole films for methanol and formic acid oxidations. The behaviour of this modified electrode was characterised in acidic media (0.1M HClO_4). The electrodes exhibited excellent long-term stability in this media. After the modification and optimisation, the electrocatalytic properties of polypyrrole-metal particles and kinetics of the oxidation reactions were interpreted with regard to fuel cell applications.
Purification And Partial Characterisation Of Superoxide Dismutase From Chicken Erythrocytes, Tüli̇n Aydemi̇r, Leman Tarhan
Purification And Partial Characterisation Of Superoxide Dismutase From Chicken Erythrocytes, Tüli̇n Aydemi̇r, Leman Tarhan
Turkish Journal of Chemistry
Superoxide dismutase (SOD), which plays a very important role in protecting organisms from oxygen toxicity, was purified from chicken erythrocyte and partially characterised. Erythrocyte membranes were disintegrated via freeze-thaw methods in the presence of Triton X-100. Following ethanol precipitation, SOD-containing solution was applied to DEAE-cellulose and then Sephadex G-100 gel columns. Chicken erythrocyte SOD was purified 508-fold with a specific activity of 8,480 units per mg. The molecular weight was estimated to be 30.6 kDa \pm 0.4 by gel filtration. The enzyme was composed of two subunits of equal size and contained one atom of copper and one atom of …
Voltammetry Of The Anticancer Drug Mitoxantrone And Dna, Arzum Erdem, Mehmet Özsöz
Voltammetry Of The Anticancer Drug Mitoxantrone And Dna, Arzum Erdem, Mehmet Özsöz
Turkish Journal of Chemistry
The interaction of mitoxantrone (MTX) with calf thymus double-stranded DNA (dsDNA) and calf thymus single-stranded DNA (ssDNA) was studied electrochemically by using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) at a carbon paste electrode (CPE). The changes in the experimental parameters (the concentration of MTX, the concentration of DNA and the accumulation time of MTX) were studied by DPV; in addition, the detection limit and the reproducibility were determined. It was observed for the interaction of MTX with dsDNA and ssDNA that the signal of the bare electrode was higher than the signal of the dsDNA modified CPE. The …
Heavy Metal Contents Of Lake Sapanca, Nevi̇n Yalçin, Vahdetti̇n Sevi̇nç
Heavy Metal Contents Of Lake Sapanca, Nevi̇n Yalçin, Vahdetti̇n Sevi̇nç
Turkish Journal of Chemistry
The heavy metal pollution of Lake Sapanca located in the Marmara region (Turkey), was investigated over time. The lake is the drinking water source of the city of Adapazarı and its environs. The D-80 (TEM) motorway passes about 5 km along the lake's zero point in the Sapanca district. The motorway's wastewater drainages have been connected to the lake without having been subjected to any wastewater treatment. The motorway was opened to service in October 1990. Analyses were performed in 1991 and were repeated in 1999 in order to observe changes in Pb, Fe and Zn contents. Samples were collected …
Photocuring Of Acrylate Oligomers In The Presence Of Vinyl Phosphonic Acids As A Flame Retarding Monomer And The Properties Of The Cured Films, Tüli̇n İmamoğlu, Yusuf Yağci
Photocuring Of Acrylate Oligomers In The Presence Of Vinyl Phosphonic Acids As A Flame Retarding Monomer And The Properties Of The Cured Films, Tüli̇n İmamoğlu, Yusuf Yağci
Turkish Journal of Chemistry
Photocuring of formulations containing polyurethane based acrylates and a flame retarding monomer (FR), namely vinyl phosphonic acid with an \alpha -cleavage type photoinitiator; 2-hydroxy-2-methylphenyl propane-1-one were studied. The flame retardancy, and the physical and mechanical properties of the cured films were determined.
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
The Sorption Of Metals On The Polysulfone Cation Exchange Membranes, Mustafa Ersöz, İlkay Hi̇lal Güğül, Aysel Çi̇men, Betül Leylek, Sali̇h Yildiz
Turkish Journal of Chemistry
The sorption of NaCl and CaCl_2 and monovalent-divalent cation salt mixtures on the polysulfone and polysulfone with polyester support cation exchange membranes were investigated. The sorption of monovalent-divalent cation salt mixtures in contact with NaCl+CaCl_2 salt mixtures were studied at a total concentration of 0.05 M. The obtained results for polysulfone type membranes were compared with Neosepta CL-25T and CM2 cation exchange membranes.
Evidence For A Hybrid Ping Pong-Semirandom Mechanism For Human Jejunal Glutathione Disulfide Reductase, Nazmi̇ Özer, İzzet Hamdi̇ Öğüş
Evidence For A Hybrid Ping Pong-Semirandom Mechanism For Human Jejunal Glutathione Disulfide Reductase, Nazmi̇ Özer, İzzet Hamdi̇ Öğüş
Turkish Journal of Chemistry
Initial rate versus substrate concentration, [S], profiles (at pH 7.4, 37^oC) for human jejunal glutathione disulfide reductase indicated partial substrate inhibition by GSSG at fixed [NADPH] \le 40 \mu M. Saturation by NADPH assumed an increasingly sigmoidal character at fixed [GSSG] \ge 20 \mu M. The results were interpreted in terms of a hybrid ping pong-semirandom mechanism proceeding through both E.NADPH (ping pong pathway) and E.GSSG (ordered pathway) complexes. When V(apparent) versus [GSSG] and [NADPH] were plotted, hyperbolic curves were obtained. Plotting 1/Vm(apparent) versus 1/[NADPH] and 1/[GSSG] yielded two lines with different slopes but intersecting at the same point on …
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Studies On The Thermal Decomposition Of Copper (Ii) Flouride Complexes With Various Amino Acids In Nitrogen Atmosphere, Muhammad Arif, Saeed-Ur Rehman, Muhammad Arshad, Khalid Masud, Nasima Arshad
Turkish Journal of Chemistry
Thermal decomposition reactions of various copper (II) fluoride complexes of the general type Cu (L) F.xH_2O (L= asparagine(asp), arginine (arg), methionine (meth) and proline (pro), x = 3 to 4) have been studied in nitrogen atmosphere using TG and DTA techniques. A possible mechanism of decomposition is suggested on the basis of the reactions of their pyrolysis. The residues obtained at the end of various decomposition processes were identified through IR spectrometry. The kinetic parameters such as energy of activation (E^o ) and order of reaction (n) were also determined.
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Photochemically-Induced Fluorescence Properties And Determination Of Flufenamic Acid, A Non-Steroidal Anti-Inflammatory Drug, In Urine And Pharmaceutical Preparation, Lei̇la Bettaieb, J. J. Aaron
Turkish Journal of Chemistry
The photochemically-induced fluorescence (PIF) properties of flufenamic acid (FF), a non-steroidal anti-inflammatory drug (NSAID) were investigated in acidic (pH 1.0) aqueous solutions at room temperature. An optimization procedure, including the effects of UV irradiation time, pH and solvent, was established for the determination of FF. A linear logarithmic calibration plot was obtained over a wide concentration range of four orders of magnitude. A low limit of detection of 0.14 ng/mL was found. The relative standard deviation (RSD) was 6.6% . The PIF method was applied to the quantitative analysis of FF in urine and in a pharmaceutical preparation with satisfactory …
Synthesis And Characterization Of Copper(Ii), Nickel(Ii), Cadmium(Ii), Cobalt(Ii) And Zinc(Ii) Complexes With 2-Benzoyl-3-Hydroxy-1-Naphthylamino-3-Phenyl-2-Propen-1-On, Mehmet Sönmez
Turkish Journal of Chemistry
Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of 2-Benzoyl-3-hydroxy-1-naphthylamino-3-phenyl-2-propen-1-on, which is a derivative of carboxamide, were prepared and characterized by elemental, spectral and magnetic methods. Based on the analytical results, electronic and infrared spectral data and magnetic susceptibility measurements, suitable structures have been proposed. The formation of the complexes in solution was investigated conductometrically. 2-Benzoyl-3-hydroxy-1-naphthylamino-3-phenyl-2-propen-1-on was found to be a bidentate ligand coordinating through enolic oxygen and amide nitrogen. The complexes of Co(II) and Ni(II) are proposed to have an octahedral structure, while Cd(II), Cu(II) and Zn(II) are suggested to possess a square-planar environment in the complexes.
Reaction Mechanism And Kinetics Of Aqueous Solutions Of 2-Amino -2 Methyl-1,3- Propanediol And Carbonyl Sulphide, Erdoğan Alper
Reaction Mechanism And Kinetics Of Aqueous Solutions Of 2-Amino -2 Methyl-1,3- Propanediol And Carbonyl Sulphide, Erdoğan Alper
Turkish Journal of Chemistry
The mechanism and kinetics of the reaction between aqueous solutions of COS and a sterically hindered primary amine, 2-amino-2-methyl-1,3-propanediol (AMPD), were investigated at 288-303 K using a stopped-flow technique. It was found that the reaction order according to power law kinetics was between 1.12 and 1.16 for an amine concentration range of 0.5 to 1.5 kmol m^{-3} . This overall order indicated that the thiocarbamate formation was complex and possibly involved a zwitterion intermediate. However, the experimental results can also be explained in terms of a single-step termolecular reaction mechanism. The kinetic rate parameters for aqueous AMPD solutions were obtained …
Copper Extraction From Aqueous Solution By Pentaerythrityl Tetrabenzylamine, Derya Kara, Mahi̇r Alkan, Ümi̇t Çakir
Copper Extraction From Aqueous Solution By Pentaerythrityl Tetrabenzylamine, Derya Kara, Mahi̇r Alkan, Ümi̇t Çakir
Turkish Journal of Chemistry
The extraction of copper(II) from the aqueous phase with pentaerythrityl tetrabenzylamine (PETBA), which was synthesized from pentaerythrityl tetrabromide and benzyl amine, was studied. The influences of ionic strength, extraction time, pH and temperature were evaluated. The extraction results showed that the ionic strength had no effect on extraction efficiency and that the extraction equilibrium was established in a few minutes. The extraction percentage was independent of pH up to pH 7.6 and then decreased gradually to zero at about pH 11.5. The stoichiometry of the compound formed was estimated to be Cu_2L(NO_3)_4, where L is PETBA. It was concluded that …
Evaluation Of Sample Pre-Treatment Procedures For The Determination Of Cr, Ni And V In Biological Matrices By Etaas, Jan Medved, Jana Kubova, Eva Chmielewska, Vladimir Stresko
Evaluation Of Sample Pre-Treatment Procedures For The Determination Of Cr, Ni And V In Biological Matrices By Etaas, Jan Medved, Jana Kubova, Eva Chmielewska, Vladimir Stresko
Turkish Journal of Chemistry
Electrothermal atomic absorption spectrometry (ETAAS) was applied for the determination of chromium, nickel and vanadium in biological materials (earthworms, feather, lucerne). Three different decomposition procedures of biological matrices are presented. The utilization of NH_4H_2PO_4, Mg(NO_3)_2 and Pd(NO_3)_2+ Mg(NO_3)_2 as chemical modifiers are investigated and compared. Optimal temperature conditions for the electrothermal determination of Cr, Ni and V are selected. Precision of the determination expressed as relative standard deviations for Cr, Ni and V varied from 6 to 22% . The detection limits are for Cr 8 \\mu g kg^{ - 1}, Ni 12 \\mu g kg^{ - 1}, and V …
Silver Recovery From Waste Photographic Films By Using Enzymatic Method, Nuri̇ Naki̇boğlu, Duygu Toscali, İhsan Yaşa
Silver Recovery From Waste Photographic Films By Using Enzymatic Method, Nuri̇ Naki̇boğlu, Duygu Toscali, İhsan Yaşa
Turkish Journal of Chemistry
A different enzymatic method was developed for stripping the silver from waste X-ray photographic films. The silver having purity of > 99% was recovered by smelting the obtained slurry in the presence of borax. Enzyme extract, obtained from Bacillus subtilis ATCC 6633 by modifying Horikoshi medium, was used for stripping the silver layer. The metal impurities (Al, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Sn) in the recovered silver were determined using the ICP-MS method. The results were compared those in with literature for high purity silver using the same method.
Magnitudes Of Back Diffusion During Long-Term Diffusive Sampling Of Volatile Organic Compounds Using Carbotrap And Chromosorb 106, Naci̇ye Kiliç, James A. Ballantine
Magnitudes Of Back Diffusion During Long-Term Diffusive Sampling Of Volatile Organic Compounds Using Carbotrap And Chromosorb 106, Naci̇ye Kiliç, James A. Ballantine
Turkish Journal of Chemistry
The aim of the research was to investigate the magnitudes of the losses of some volatile organic compounds from the solid adsorbents, Carbotrap and Chromosorb 106 due to back diffusion during long-term diffusive sampling of volatile organic compounds in the environment. Experiments were performed by loading the compounds to be tested on the adsorbent tubes and leaving them in an outdoor environment to simulate the real life sampling conditions over a 14 day period. The losses due to back diffusion were investigated for both the high and the low initial concentrations of the fourteen compounds covering a wide range of …
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.
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.
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 …
Properties Of Electrodeposited Cadmium Sulfide Films For Photovoltaic Devices With Comparison To Cds Films Prepared By Other Methods, Fi̇gen Kadirgan, Duli Mao, Wenjie Song, Tim Ohno, Brian Mccandless
Properties Of Electrodeposited Cadmium Sulfide Films For Photovoltaic Devices With Comparison To Cds Films Prepared By Other Methods, Fi̇gen Kadirgan, Duli Mao, Wenjie Song, Tim Ohno, Brian Mccandless
Turkish Journal of Chemistry
Films of CdS for photovoltaic devices were electrochemically deposited on tin oxide coated glass substrates at different conditions. The films were found to be smooth and uniform with a small grain size. X-ray diffraction measurement and analysis indicated a hexagonal phase rather than the cubic phase. The surface composition of the films was investigated by Auger Spectroscopy. Electrochemical deposition parameters were studied to obtain the optimum conditions for the best CdS films. Our films are compared from the pinhole number and particulate point of view with the films prepared by other methods.
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 …
Fundamental Noise Studies In Flame Atomic Magneto-Optic Rotation And Atomic Absorption Spectrometry, Ahmet T. İnce, Richard D. Snook, Jhon B. Dawson
Fundamental Noise Studies In Flame Atomic Magneto-Optic Rotation And Atomic Absorption Spectrometry, Ahmet T. İnce, Richard D. Snook, Jhon B. Dawson
Turkish Journal of Chemistry
A study of inherent noise sources present in a purpose built flame atomic magneto-optic rotation (AMOR) spectrometer system was carried out with a view to identifying their sources. Two different optical configurations were employed, a crossed polariser and a 45° offset polariser configuration. The offset polariser configuration was operated in both an AMOR and atomic absorption (AA) mode for the noise measurements. Two main interference frequencies were found to occur in all the optical measurement modes. An interference flame feature frequency (15.5 Hz -39.0 Hz) which arose from an ``organ-pipe'' effect in the gas flow through the flame cooling sheets. …
Auxiliary Controlled Intramolecular 1,3-Dipolar Cycloaddition Reactions Of Chiral Azomethine Ylides, Özdemi̇r Doğan, Philip P. Garner
Auxiliary Controlled Intramolecular 1,3-Dipolar Cycloaddition Reactions Of Chiral Azomethine Ylides, Özdemi̇r Doğan, Philip P. Garner
Turkish Journal of Chemistry
Intramolecular 1,3-dipolar cycloaddition reactions of chiral azomethine ylides obtained by thermal ring opening of chiral aziridines 7a, b and 8a, b are investigated. Synthesis of these aziridines 7a, b and 8a, b is described.
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.
Studies On The Methylation Of 5-Nitro-Benzimidazoles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus
Studies On The Methylation Of 5-Nitro-Benzimidazoles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus
Turkish Journal of Chemistry
Methylation of 2H, 5-nitro- (1) and 2-ethyl, 5-nitro- (2) benzimidazoles separately with methyl iodide in acetone in the presence of potassium carbonate yielded 2H, 5/6-nitro-(3A and 3B) and 2-ethyl, 5/6-nitro- (4A and 4B) methylbenzimidazoles respectively. Methylation of 1 and 2 in dimethylformamide in place of acetone yielded not only 3A, 3B and 4A, 4B respectively, but in addition 1,3-dimethyl-5-nitro-benzimidazol-2-one (5) was also obtained in each case. The structure of the synthesized compounds was determined with the help of mass and ^1H NMR spectroscopic analysis.
Specific Determination Of Hydrogen Peroxide With A Catalase Biosensor Based On Mercury Thin Film Electrodes, F. Ni̇l Ertaş, Suna Ti̇mur, Erol Akyilmaz, Erhan Di̇nçkaya
Specific Determination Of Hydrogen Peroxide With A Catalase Biosensor Based On Mercury Thin Film Electrodes, F. Ni̇l Ertaş, Suna Ti̇mur, Erol Akyilmaz, Erhan Di̇nçkaya
Turkish Journal of Chemistry
A biosensor for specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.6) in combination with a mercury film electrode. Catalase was immobilized with gelatine by means of glutaraldehyde on the electrode surface. The biosensor response was monitored by following the reduction peak of dissolved oxygen at around -0.24 V. The peak current changes upon addition of hydrogen peroxide and gives a linear response in a concentration range of 1-50 x 10^{-6} M within a response time of 3 minutes.
The Synthesis Of Manganese(Iii) Acetate In Bipolar Packed-Bed And Trickle-Bed Electrode Cells, Altan Güvenç, Belgi̇n Karabacakoğlu, Ö. Mete Koçkar, A. Tarik Pekel
The Synthesis Of Manganese(Iii) Acetate In Bipolar Packed-Bed And Trickle-Bed Electrode Cells, Altan Güvenç, Belgi̇n Karabacakoğlu, Ö. Mete Koçkar, A. Tarik Pekel
Turkish Journal of Chemistry
In this research, the electrochemical oxidation of Mn(II) acetate to Mn(III) acetate was investigated in aqueous acetic acid solution, using a bipolar particulate electrode cell. In order to determine the effect of flow modes on the yield of Mn(III) acetate, which is an important oxidizing agent and catalyst in organic reactions, a bipolar particulate electrode cell was employed both in flooded and trickle flow modes. The experiments were conducted at controlled potentials of 50-250 volts using the solution (10% H_2O, 90% CH_3COOH, 0.1 M Mn(CH_3COO)_2.4H_2O, 0.1 M CH_3COONa.3H_2O) and at an optimum flow rate of 0.04 ml.s^{-1}. The values of …