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Articles 31 - 55 of 55
Full-Text Articles in Physical Sciences and Mathematics
Voltammetric Determination Of Salbutamol Based On Electrochemical Oxidation At Platinum And Glassy Carbon Electrodes, Niyazi Yilmaz, Sibel A. Özkan, Bengi Uslu, Zühre Şentürk, İnci Bi̇ryol
Voltammetric Determination Of Salbutamol Based On Electrochemical Oxidation At Platinum And Glassy Carbon Electrodes, Niyazi Yilmaz, Sibel A. Özkan, Bengi Uslu, Zühre Şentürk, İnci Bi̇ryol
Turkish Journal of Chemistry
The oxidative behavior of salbutamol was studied as a function of pH at platinum and activated glassy carbon electrodes. Between pH 1.9 and 12.0, the drug was characterized by a single oxidation step at both electrodes. The process was found to be dependent on the nature and the pH of the supporting elctrolyte. The procedure yielded a linear concentration range of $1 \times 10^{-4}$ to $1 \times 10^{-3}$ M and $2 \times 10^{-5}$ to $1 \times 10^{-3}$ M in 0.2 M sulphuric acid and a phosphate buffer of pH 6, at platinum and glassy carbon electrodes, respectively. The method was …
Pixe, Particel Induced X-Ray Emission A Concise Review, A. İnhan Gari̇p
Pixe, Particel Induced X-Ray Emission A Concise Review, A. İnhan Gari̇p
Turkish Journal of Chemistry
PIXE-Particle Induced X-Ray Emission is a multielemental, sensitive and non-estructive method which has been in use in trace elemental analysis since 1970. This review aims to explain the main features of PIXE. References will be given at the end for those that seek more detailed knowledge on the principles and applications of this technique.
Theoretical Studies On The Configurations Of Benzhomobarrelene Derivatives, Rıza Abbasoğlu, Abdullah Menzek, Metin Balci
Theoretical Studies On The Configurations Of Benzhomobarrelene Derivatives, Rıza Abbasoğlu, Abdullah Menzek, Metin Balci
Turkish Journal of Chemistry
Reaction of 7-carbomethoxy-cycloheptatriene with benzyne resulted in the formation of only one benzhomobarrelene isomer, {\bf 5A}. Theoretically, four addition products, {\bf 5A-D}, can be formed from this reaction. Certain molecular mechanic calculations (MM2 force field) have been undertaken on these isomers. It has been shown that the isomers {\bf 5A} and {\bf 5C} have the lowest energies. The non-existence of {\bf 5C} has been discussed in terms of a benzyne approach to a norcaradiene structure. Furthermore, MM2 calculations on two different conformers of {\bf 5A} have revealed that the bisected conformer {\bf 5AE} has the highest strain energy. However, AM1 …
Indirect Complexometric Determination Of Mercury Using Potassium Iodide As Selective Masking Agent, B. Muralidhara Rao
Indirect Complexometric Determination Of Mercury Using Potassium Iodide As Selective Masking Agent, B. Muralidhara Rao
Turkish Journal of Chemistry
This paper describes a indirect complexometric method for the determination of mercury in the presence of co-ions, based on the selective masking ability of potassium iodide. To the mixture of mercury (II) and other metal ion solution, EDTA solution was added in excess of the metal ions present. The pH of the solution was adjusted to 5.0-6.0 using solid hexamine ($10 \pm 2$ g) and surplus EDTA was titrated with zinc sulfate solution using xylenol orange indicator. An excess of solid potassium iodide was then added to decompose the Hg-EDTA complex and the released EDTA was titrated with standard zinc …
Optimization Of Starting Time And Period Of Induction And Inducer Concentration In The Production Of The Restriction Enzyme Ecori From Recombinant Escherichia Coli 294, Candan Yildir Tamerler, Z. İlsen Önsan, Betül Kirdar
Optimization Of Starting Time And Period Of Induction And Inducer Concentration In The Production Of The Restriction Enzyme Ecori From Recombinant Escherichia Coli 294, Candan Yildir Tamerler, Z. İlsen Önsan, Betül Kirdar
Turkish Journal of Chemistry
Induction parameters including inducer concentration, period of induction and the cell concentration at which inducer is to be added to the fermentation broth were optimized in order to increase the yield of the {\em Eco}RI restriction endonuclease isolated from recombinant {\em E. coli}. Bacterial cells harboring the plasmid pPG430 containing {\em Eco}RI endonuclease and the methylase genes under the control of {\em lac} promoter were used in the experiments where induction was accomplished by using lactose isopropyl-$\beta$-D-thiogalactoside (IPTG). An IPTG concentration of 0.1mM, the late exponential phase of growth (at an optical density of 1.2 at 595 nm) and an …
Removal Of Water-Soluble Cationic Dyes With Trisyl Silicas, Erdener Karadağ, Dursun Saraydin, Fatma Aydin
Removal Of Water-Soluble Cationic Dyes With Trisyl Silicas, Erdener Karadağ, Dursun Saraydin, Fatma Aydin
Turkish Journal of Chemistry
In this study, the adsorption of certain water-soluble cationic dyes, (basic blue 9, basic blue 12, basic blue 17, brilliant cresyl blue, janus green B, basic green 4, basic violet 1, basic violet 3, and thionin) onto TriSyl silicas by batch adsorption at 25^oC was investigated. In the adsorption experiments, Langmuir type adsorption in the Giles classification system was found. Binding parameters such as the initial binding constant (K$_i$), the equilibrium binding constant (K), monolayer coverage(n), site-size(u), maximum fractional occupancy ($\hat{\theta}$), and the thermodynamic parameter free energy of adsorption $(\Delta G)$ were calculated for TriSyl silica and cationic dye systems …
Reactions Of 4-Amino-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones And 4-Amino-4h-1,2,4-Triazoles With Some Carboxylic Acid Anhydrides, Şule Bahçeci̇, Nurhan İnce, Asun İki̇zler
Reactions Of 4-Amino-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones And 4-Amino-4h-1,2,4-Triazoles With Some Carboxylic Acid Anhydrides, Şule Bahçeci̇, Nurhan İnce, Asun İki̇zler
Turkish Journal of Chemistry
3-Alkyl(Aryl)-4-tetrachlorophthalimido-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) and 3-alkyl(aryl)-4-(1,8-naphthalimido)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were synthesized from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with tetrachlorophthalic anhydride and 1,8-naphthalic anhydride, respectively. In addition, the reactions of 4-amino-4H-1,2,4-triazoles (4) with succinic anhydride and phthalic anhydride were studied.
Cu And Pb Adsorption On Some Bentonitic Clays, Oğuz İnel, Fehmi Albayrak, Ayşgül Aşkin
Cu And Pb Adsorption On Some Bentonitic Clays, Oğuz İnel, Fehmi Albayrak, Ayşgül Aşkin
Turkish Journal of Chemistry
Cu$^{2+}$ and Pb$^{2+}$ adsorption isotherms were measured on some clay samples obtained from various regions of Turkey. Also specific surface areas of clays were determined from adsorption data of ortho-phenanthroline(OP). The adsorptions of ions and OP were studied using the batch equilibration technique as a function of adsorbate concentration. The adsorption data, over the whole range of concentrations used, follow the Langmuir adsorption isotherm. The retention capacities of the adsorbates and the cation exchange capacities of the clays were determined. Plots of K$_d$, the distribution coefficient of ions between the solid and solution phases, vs. $\Gamma$, the surface density of …
The Effectof Lanthanum And Barium Additives On The Thermal Stabilization Of \Gamma-Al_2o_3, A. İnci İşli̇, A. Erhan Aksoylu, Z. İlsen Önsan
The Effectof Lanthanum And Barium Additives On The Thermal Stabilization Of \Gamma-Al_2o_3, A. İnci İşli̇, A. Erhan Aksoylu, Z. İlsen Önsan
Turkish Journal of Chemistry
The effect of La and Ba additives on the thermal stabilization of $\gamma$-Al$_2$O$_3$ was investigated through total-surface-area measurements. The parameters considered were additive content, calcination temperature, and calcination period. The effect of precalcination was also studied. It was found that thermal stabilization caused by 3 wt\% La and Ba is superior to 6 wt \% La or Ba, and the positive effect of 3 wt\% La and 3 wt\% Ba are almost identical. The nearly threefold increase in the total surface area of 3 wt\% La or Ba doped samples calcined above the $\gamma - \alpha$ phase-transition temperature indicates that …
Synthesis Of New Bisamidoxime Ligands And Their Monocharged Metal Complexes, Niyazi Biçak, Tülay Atay
Synthesis Of New Bisamidoxime Ligands And Their Monocharged Metal Complexes, Niyazi Biçak, Tülay Atay
Turkish Journal of Chemistry
This paper describes the synthesis of two new bisamidoxime ligands with dithioether connecting groups. The ligands were obtained from ethane dithiol in two steps; i) cyanoalkylation ii) oximation with hydroxylamine. Cyanoalkylation of ethanedithiol was carried out by condensing with chloro acetonitrile and base-catalysed addition of acrylonitrile, yielding bis(cyanomethylthio) ethane and bis(cyanoethyl thio) ethane, respectively. Upon subsequent oximation with hydroxylamine, these bisnitrile compounds gave corresponding bis(amidoxime) ligands in reasonable yields. The ligands behave as tetradentate ligands and on interaction with Cu(II), Ni(II), Co(II) chlorides produces monocharged metal complexes in a [ML]$^+$Cl$^-$ composition.
Crystal Structure Of Dichlorodiaquabis-(P- Dimethylaminobenzaldehyde)Manganese(Ii), Veysel T. Yilmaz, Turan K. Yazicilar, Halis Ölmez, R. Alan Howie
Crystal Structure Of Dichlorodiaquabis-(P- Dimethylaminobenzaldehyde)Manganese(Ii), Veysel T. Yilmaz, Turan K. Yazicilar, Halis Ölmez, R. Alan Howie
Turkish Journal of Chemistry
The crystal structure of dichlorodiaquabis-($p$-dimethylaminobenzaldehyde)manganese(II), [MnCl$_2$(OH$_2$)$_2$(C$_9$H$_{11}$NO)$_2$], was determined from X-ray intensity data. The structure consists of the isolated molecules of the complex. The central Mn atom in the complex is coordinated by txo $p$-dimethylaminobenzaldehyde and two water molecules and also two chlorine atoms, resulting in a distorted octahedral environment. The same molecules or ions occupy {\it trans} positions. The crystal structure is stabilized by weak hydrogen bonds present between the isolated molecules.
Electrochemical Polymerization And Analysis Of Some Aniline Derivatives, Bekir Sari, Muzaffer Talu
Electrochemical Polymerization And Analysis Of Some Aniline Derivatives, Bekir Sari, Muzaffer Talu
Turkish Journal of Chemistry
In this study, conductive homopolymers of o-chloroaniline, p-bromoaniline and N-methylaniline were synthesized electrochemically in perchloric acidic solution and their properties were analyzed. Initially, the maximum oxidation potential values of these monomer solutions were determined by Cyclic Voltammetry (CV). Their conductive polymers were then synthesized under a nitrogen atmosphere using a potentiostat. FTIR spectra were taken in order to analyze the structural properties of the resulting polymers. Thermogravimetric analysis (TGA) was conducted and surface micrographs were taken by a Scanning Electron Microscope (SEM). The conductivity levels of the polymers were determined by the Four Probe technique. Magnetic properties of the samples …
Electron Spectroscopy For Material Characterization, Ş. Süzer
Electron Spectroscopy For Material Characterization, Ş. Süzer
Turkish Journal of Chemistry
Basic principles of the two electron spectroscopic techniques, the x-ray photoelectron spectroscopy, XPS, and the Auger electron spectroscopy, AES, are given. Their utilization in material characterization are introduced through examples with application of these techniques to various surface related problems.
Fatty Acid Composition And Cholesterol Content Of Some Turkish Fish Species, Sedat İmre, Serap Sağlik
Fatty Acid Composition And Cholesterol Content Of Some Turkish Fish Species, Sedat İmre, Serap Sağlik
Turkish Journal of Chemistry
It is well known that fish lipids are effective against cardiovascular diseases due to their high contents of polyunsaturated omega-3 (n-3) fatty acids. In order to determine a suitable fish diet, the fatty acid compositions and total lipid and cholesterol contents of 9 common fish species obtained from the central fish market in Ğstanbul were determined. Palmitic (C-16:0) and oleic acid (C-18:1) were the predominant saturated and monounsaturated fatty acids. The predominant polyunsaturated fatty acids were eicosapentaenoic (C-20:5) acid and docosahexaenoic (C-22:6) acid. The amounts of cholesterol in fish lipids did not differ significantly. Sardine ({\it Sardina pilchardus}) and mackerel …
Voltammetric Determination Of Thioridazine Hydrochloride, İnci Bi̇ryol, Saadet Dermi̇ş
Voltammetric Determination Of Thioridazine Hydrochloride, İnci Bi̇ryol, Saadet Dermi̇ş
Turkish Journal of Chemistry
This study describes the optimal conditions for the determination of Thioridazine HCl (Tz-HCl) in 0.2 M sulphuric acid by voltammetry using ruthenium (Ru), platinum (Pt) and glassy carbon (GC) electrodes. A new and sensitive method is described for electrochemical determination of Tz-HCl in the concentration range $5.10^{-5} - 10^{-3}$ M (20.35-407 $\mu$gml$^{-1}$); $6.10^{-4} - 10^{-2}$ M (244.2 - 4070 $\mu$gml$^{-1}$); $10^{-4} - 10^{-3}$ M (40,7 - 407 $\mu$gml$^{-1}$), with Ru, Pt and glassy carbon electrodes, respectively. The method was applied successfully to the determination of Tz-HCl in pure form or incorporated in their representative pharmaceutical preparations. The precision of the …
Polarographic Studies On The Kinetics Of The Electrode Reaction Of 4-Benzoyl-1,5 Diphenyl Pyrazole-3-Carboxylic Acid, M. Veri̇rşen, S. Erturan
Polarographic Studies On The Kinetics Of The Electrode Reaction Of 4-Benzoyl-1,5 Diphenyl Pyrazole-3-Carboxylic Acid, M. Veri̇rşen, S. Erturan
Turkish Journal of Chemistry
The polarographic behavior of 4-Benzoyl-1,5 diphenyl pyrazole-3- Carboxylic acid (BDPPCA) in aqueous ethanol solution (76 \% v/v) at 25^oC was studied as a function of pH using Mcl buffer solution. One well-defined wave was obtained in the pH range of 3.3-5.4. This wave, corresponding to two electron reduction processes, was irreversible and diffusion controlled. However, in the pH range of 5.4-7.4 a single reversible and diffusion-controlled wave involving two electrons resulted. The kinetic parameters $(n_a, k^o_{f,h})$ were calculated by Koutecky's method. A tentative mechanism was put forward for the reduction process of depolarizer. Furthermore, the effects of different supporting electrolytes …
Determination Of Structure-Toxicity Relationship Of Amphiprotic Compounds By Means Of The Inhibition Of The Dehydrogenase Activity Of Pseudomonas Putida, Ş. Gül, D. Öztürk
Determination Of Structure-Toxicity Relationship Of Amphiprotic Compounds By Means Of The Inhibition Of The Dehydrogenase Activity Of Pseudomonas Putida, Ş. Gül, D. Öztürk
Turkish Journal of Chemistry
Aliphatic and aromatic alcohols are amphiprotic compounds which have both polar and nonpolar parts in their structure. These compounds were studied with respect to the nonreactive toxic effects on the microorganism {\it Pseudomonas putida}. The toxicity of these chemicals to aerobic bacterium {\it P. putida} was measured in terms of inhibition of dehydrogenase activity. The test results, expressed as concentration of chemicals 50\% effective in inhibition (IC$_{50}$), were correlated with their physicochemical properties such as aqueous solubility (S) and octanol-water partition coefficient (P).
Comparison Of Different Production Processes For Bioethanol, B. Çaylak, Fazilet Vardar Sukan
Comparison Of Different Production Processes For Bioethanol, B. Çaylak, Fazilet Vardar Sukan
Turkish Journal of Chemistry
In this study, ethanol was produced with the microorganism {\em Saccharomyces cerevisiae} by using sucrose as a substrate. Batch processes were tested by using the same substrate, microorganism and medium composition. {\em Saccharomyces cerevisiae}, used in the free form in the first group of experiments, was immobilized by different methods. In the second group of experiments agar, sponge and a natural material called luffa cylindrica fiber were used as support materials. The batch processes with free and immobilized microorganisms were compared with respect to efficiency and yield.
The Effectof Temperature On The Dynmaic Viscosity Of Acetone Sunflower-Seed Oil Mixtures, Hüseyin Topallar, Yüksel Bayrak
The Effectof Temperature On The Dynmaic Viscosity Of Acetone Sunflower-Seed Oil Mixtures, Hüseyin Topallar, Yüksel Bayrak
Turkish Journal of Chemistry
The effect of acetone on the dynamic viscosity of sunflower-seed oil was studied under a dynamic heating regime at temeparuters ranging from 25^oC to 50^oC at 5^oC intervals. Acetone dramatically reduced the viscosity of sunflower-seed oil. The reduction of viscosity was far less with further addition of acetone. A linear relationship was found between the density of sunflower-seed oil and temperature. The influence of a solvent on the density of the sunflower-seed oil/acetone solution can be accounted for by the mixing theory of ideal solutions, whereas the effect of temperature on the dynamic viscosity of the oil solution is best …
Solvent Extraction Of La^{3+} Withethylenediamine-N,N'-Ditetradecyl-N,N'-Diacetic Acid(Eddat) In Dichloromethane, Mürüvvet Yurdakoç, Halil Hoşgören
Solvent Extraction Of La^{3+} Withethylenediamine-N,N'-Ditetradecyl-N,N'-Diacetic Acid(Eddat) In Dichloromethane, Mürüvvet Yurdakoç, Halil Hoşgören
Turkish Journal of Chemistry
Ethylenediamine-N,N'-ditetradecyl-N,N'-diacetic acid (EDDAT) was synthesized for the solvent extraction of La$^{3+}$. EDDAT was prepared from ethylenediamine-N,N'-diacetic acid (EDDA) and tetradecyl bromide in a basic n-amylalcohol-ethanol-water solvent system. The structure of this new extracting reagent was identified according to spectroscopic data, i.e. $^{13}$C NMR, $^1$H NMR, and elemental analysis results. The solvent extraction of La$^{3+}$ with EDDAT in dichloromethane was studied as a function of parameters of the aqueous and organic phases. The optimal extraction conditions were determined. The extraction yield increased with a decrease in hydrogen ions in the aqueous phase. Stripping of the La$^{3+}$ loaded organic phase was achieved …
Separation Of Molybdenum, Vanadium And Nickel By Liquid-Liquid Extraction, T. Coşar, R. Zi̇yadanoğullari
Separation Of Molybdenum, Vanadium And Nickel By Liquid-Liquid Extraction, T. Coşar, R. Zi̇yadanoğullari
Turkish Journal of Chemistry
Elements in the ash of asphaltites that is used in thermal central for power generation units are Mo, V, U, Ti and Ni. The main goal of this study was to separate molybdenum, vanadium and nickel from the aqueous solution. The quantities of the above elements in solution were in the range of 50-80 ppm. The separate these elements from solution, the liquid-liquid extraction method was applied to samples. Alamine 336 was used as extractant. During the reduction-oxidation processes, single and multiple extraction methods were applied to the solution in combination. The quantities of molybdenum, vanadium and nickel in the …
Kinetic Studies Of The Thermal Decomposition Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Moazzam H. Bhatti, Sohail Mahmood, Muhammad Mazhar, M. Saleem Khalid, Nazar Hussain
Kinetic Studies Of The Thermal Decomposition Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Moazzam H. Bhatti, Sohail Mahmood, Muhammad Mazhar, M. Saleem Khalid, Nazar Hussain
Turkish Journal of Chemistry
The di- and tri-organotin complexes of general formula R$_2$SnL$_2$ and R$_3$SnL where R = C$_4$H$_9$, C$_6$H$_5$, C$_6$H$_5$CH$_2$, C$_6$H$_{11}$ and L=1-nitroso-2-naphthol, were subjected to thermal decomposition by means of thermogravimetry (TG). The decomposition occurred in steps and the kinetics of every set of reactions were determined using the method described by Coats and Redfern. These results were analysed to establish the decomposition kinetics and hence to calculate activation energies. The activation energies were also determined by applying the method described by Horowitz, which yielded comparable results.
On The Türker Angles In The Theory Of Total \Pi-Electron Energy, Ivan Gutman
On The Türker Angles In The Theory Of Total \Pi-Electron Energy, Ivan Gutman
Turkish Journal of Chemistry
The Türker angles $\theta, \alpha$ and $\beta$ are quantities invented by Lemi Türker, and are used in the theory of total $\pi$-electron energy $(E)$ of unsaturated conjugated hydrocarbons. We report here expressions for $\theta, \alpha$ and $\beta$ in terms of $E$ and the parameters $n$ (= half the number of carbon atoms) and $e$ (= the number of carbon-carbon bonds). The forms of these expressions are remarkably similar. Numerical calculation performed on a representative set of benzenoid hydrocarbons reveals that the dependence of the angles $\alpha$ and $\beta$ on molecular structure is very similar, and that their ratio is almost …
Thermal Behaviour Of Some Azo Dyes Containing Sterically Hindered And Water-Soluble Groups, Hasan Kocaokutgen, Zerrin Heren
Thermal Behaviour Of Some Azo Dyes Containing Sterically Hindered And Water-Soluble Groups, Hasan Kocaokutgen, Zerrin Heren
Turkish Journal of Chemistry
Thermal behaviour of six azo dyes containing steric hindered groups such as tert-butyl, sec-butyl and isopropyl, were investigated by means of thermogravimetry (TG), differential thermal analysis (DTA) and differential thermogravimetry (DTG). The thermal decomposition points and amount of volatile pyrolysis products, were determined in nitrogen atmosphere using TG, DTA and DTG curves.
Crystal And Molecular Structure Of Tris(2,6-Dichlorophenyl) Thiophosphate, Veysel T. Yilmaz, Mustafa Odabaşoğlu, R. Alan Howie
Crystal And Molecular Structure Of Tris(2,6-Dichlorophenyl) Thiophosphate, Veysel T. Yilmaz, Mustafa Odabaşoğlu, R. Alan Howie
Turkish Journal of Chemistry
The crystal structure of tris(2,6-dichlorophenyl)thiophosphate was determined by single crystal X-ray diffractometry. The structure consists of isolated molecules and each unit cell contains 8 molecules of the compound. The crystal system is monoclinic with a space group of C2/c. The P atom is bonded to three O atoms and one S atom in a distorted tetrahedron environment.