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Articles 2551 - 2580 of 2720
Full-Text Articles in Chemistry
Characterization Of An All-Optical Device Based On Organic Materials, Hans-Martin Keller, Mark Andreas Bader, Gerd Marowsky
Characterization Of An All-Optical Device Based On Organic Materials, Hans-Martin Keller, Mark Andreas Bader, Gerd Marowsky
Turkish Journal of Chemistry
We present numerical and first experimental results for an all-optical switching device. The device consists of a periodically modulated nonlinear waveguide, where so-called gap solitons stabilize the switching process. The fabrication of Bragg gratings in different polymeric films, e.g. poly(phenylene vinylene), polydiacetylene or polystyrene by excimer laser photoablation was tested. In preparation of further experiments numerical calculations were performed to characterize the device under realistic conditions, including position dependent index modulations and absorption losses. In further time-dependent simulations the transition from the reflecting to the transparent state was investigated in detail. As a main result, the threshold intensity turns out …
Phthalocyanines And Related Compounds: Subunits For The Preparation Of Molecular Materials, J. Garcia, A. Gonzalez, A. Gouloumis, E.M. Maya, M.D. Perez, B.D. Rey, P. Vazquez, T. Torres
Phthalocyanines And Related Compounds: Subunits For The Preparation Of Molecular Materials, J. Garcia, A. Gonzalez, A. Gouloumis, E.M. Maya, M.D. Perez, B.D. Rey, P. Vazquez, T. Torres
Turkish Journal of Chemistry
The design, synthesis, structural and physical characterization and engineering, and the study of the electrical conductivity and the nonlinear optical properties of phthalocyanines and molecular substances related to them, such as subphthalocyanines, hemiporphyrazines and triazolephthalocyanines were reviewed.
Azobenzene Side-Chain Liquid Crystalline Polyesters With Outstanding Optical Storage Properties, S. Hvilsted, M. Pedersen, N.C.R. Holme, P.S. Ramanujan
Azobenzene Side-Chain Liquid Crystalline Polyesters With Outstanding Optical Storage Properties, S. Hvilsted, M. Pedersen, N.C.R. Holme, P.S. Ramanujan
Turkish Journal of Chemistry
A flexible azobenzene side-chain liquid crystalline (SCLC) polyester architecture employed for reversible optical storage is described. The modular design allows four structural parameters to be individually modified. These parameters: {\em i}- the methylene side-chain spacer length, {\em ii}- the substituent on azobenzene, {\em iii}- the methylene main-chain segment length, and {\em iv}- the polyester molecular mass, all influence the optical storage properties. A general synthetic route to novel mesogenic azobenzene diols comprising parameters {\em i} and {\em ii} is outlined. Polyesters with molecular masses (parameter {\em iv}) up to 100,000 are routinely obtained by melt transesterification of the novel diols …
Poly(3-Alkylthiophene) Modifications, A. Bolognesi
Poly(3-Alkylthiophene) Modifications, A. Bolognesi
Turkish Journal of Chemistry
No abstract provided.
Electrically Conductive Polymer Grafts Prepared By Electrochemical Polymerization Of Pyrrole Onto Poly[(Methyl Methacrylate)-Co-(2-(N-Pyrrolyl) Ethyl Methacrylate)] Electrodes, Nuran Balci, Ural Akbulut, Levent Toppare, Dietmar Stanke, Manfred L. Hallensleben
Electrically Conductive Polymer Grafts Prepared By Electrochemical Polymerization Of Pyrrole Onto Poly[(Methyl Methacrylate)-Co-(2-(N-Pyrrolyl) Ethyl Methacrylate)] Electrodes, Nuran Balci, Ural Akbulut, Levent Toppare, Dietmar Stanke, Manfred L. Hallensleben
Turkish Journal of Chemistry
Pyrrole was grafted on poly[(methyl methacrylate)-co-(2-(N-pyrrolyl) ethyl methacrylate)] (PMMA-co-PEMA) using constant potential electrolyses. The thermal stability of PMMA-co-PEMA was improved as a result of electrochemical grafting with pyrrole. The electrochemical behavior of the films was studied by cyclic voltammetry. Pyrrole was found to be electroactive on PMMA-co-PEMA electrodes.
Dimerization Of Pyrrole, Mine Yurtsever, Ersin Yurtsever
Dimerization Of Pyrrole, Mine Yurtsever, Ersin Yurtsever
Turkish Journal of Chemistry
Accurate ab-inito quantum mechanical calculations of pyrrole dimers are reported. The thermodynamical stabilities of dimers with $\alpha - \alpha, \alpha - \beta$, and $\beta - \beta$ type linkages are compared in order to predict the possibilities of branching in polypyrroles. Calculations employing large basis sets and including electron correlation effects predict the $\alpha - \alpha$ dimers as the most stable form. However, an $\alpha - \beta$ type bonding requires only 1.5-2.0 kcal/mol, and the energy necessary to introduce a $\beta - \beta$ type bond is 3.6-4.0 kcal/mol. These values show that a high degree of branching is possible even at …
Heat Treatment Of Maceral Groups Obtained From Turkish Bituminous Coals, Elif Sultan Vayi̇soğlu, Nevin Gaye Erbatur
Heat Treatment Of Maceral Groups Obtained From Turkish Bituminous Coals, Elif Sultan Vayi̇soğlu, Nevin Gaye Erbatur
Turkish Journal of Chemistry
The dilatation properties of parent coals and their maceral fractions were examined. In all the coal samples, the main petrographic constituent was the vitrinite maceral. Reflectance of the vitrinite and inertinite macerals increased after carbonization, while the liptinite maceral disappeared and caused large pores in the vitrinite macerals. All of the coals developed anisotropic coke.
Heme Transfer Reactions: An Important Prerequisite For Synthetic Oxygen Carriers, Jan Paul, Wenhua Chen, Per-Ingvar Ohlsson, Michael Smith
Heme Transfer Reactions: An Important Prerequisite For Synthetic Oxygen Carriers, Jan Paul, Wenhua Chen, Per-Ingvar Ohlsson, Michael Smith
Turkish Journal of Chemistry
Electronic changes of iron- and metal free porphyrins are reviewed in light of their importance to modify the ferri/ferro reduction potential and energy dissipation between ligated carbon monoxide and the porphyrin chelate. Substitutions at positions 2 and 4 are effective ways to exercise this influence. Other measures include exposure to water and modifications of axial ligation, including the \lq three-ligand' case. These measures will also influence the stability of recombined hemin-protein entities, as apparent from the kinetics of heme-transfer from a modified donor protein to apomyoglobin, but the stability appears to be related to the bulkiness of 2,4-substitutional groups rather …
The Amido And Bisalkoxo-Complexes Of [Tri(3,5-Dimethylpyrazolyl)Borato]Molydenum Nitrosyl, Işıl Topaloğlu
The Amido And Bisalkoxo-Complexes Of [Tri(3,5-Dimethylpyrazolyl)Borato]Molydenum Nitrosyl, Işıl Topaloğlu
Turkish Journal of Chemistry
In this study, the amido nitrosyl molybdenum complex, [Mo{HM(3,5-Me_2C_3HN_2)_3}(NO)Cl(NH_2)], was prepared. This compound reacts with alocohols, yielding the bisalkoxo complexes, [Mo{HM (3,5-Me_2C_3HN_2)_3}(NO)(OR)_{2}] (R = Me, Et, Pr^n, Bu^n). The new complexes were analyzed by IR and ^1H-NMR spectroscopy.
Thermodynamic Studies Of Some Complexes Of 2-Benzoylpyridine 4-Phenyl-3-Thiosemicarbazone, T. Atalay, E. Güler Akgemci̇
Thermodynamic Studies Of Some Complexes Of 2-Benzoylpyridine 4-Phenyl-3-Thiosemicarbazone, T. Atalay, E. Güler Akgemci̇
Turkish Journal of Chemistry
The stability constants of the Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-benzoylpyridine 4-phenyl-3-thiosemicarbazone were determined using a spectrophotometric method at different temperatures (25, 30, 35 and 40 $\pm$ 0.1^oC) and ionic strengths (0.05, 0.01 and 0.20 M KNO$_3$) in 50 \% (v/v) aqueous ethanol. Plots of thermodynamic stability constants at zero ionic strength ($\ln$ K^o) versus T$^{-1}$ gave linear curves and $\Delta$ H^o and $\Delta$ S^o were also calculated from these plots. Moreover, the changes in free energy for each metal-ligand system were calculated from the following equation. $\Delta$ G^o = -RT $\ln$ K^o.
Reaction Of 3,4-Diformyl-2,5-Dimethylpyrrole With 1,2(Substituted)Diphenyl-1,2-Diaminoethanes, Cemil Öğreti̇r, Fatma Severcan
Reaction Of 3,4-Diformyl-2,5-Dimethylpyrrole With 1,2(Substituted)Diphenyl-1,2-Diaminoethanes, Cemil Öğreti̇r, Fatma Severcan
Turkish Journal of Chemistry
3,4-Diformyl-2,5-dimethylpyrrole (1) reacts with 1,2-diphenyl-1,2-diamine derivatives to form the potentially tautomeric 2:2 macrocyclic adduct (1)=(1). ^1H and ^{13}C n.m.r. spectral data along with acidity measurements indicate that the 2-azafulvene structure (7) is predominant for all adducts.
Recovery Of Copper, Cobalt, Nickel, Cadmium, Zinc And Bismuth From Electrolytic Copper Solution, Fırat Aydin, Ömer Yavuz, Berrin Zi̇yadanoğullari, Recep Zi̇yadanoğullari
Recovery Of Copper, Cobalt, Nickel, Cadmium, Zinc And Bismuth From Electrolytic Copper Solution, Fırat Aydin, Ömer Yavuz, Berrin Zi̇yadanoğullari, Recep Zi̇yadanoğullari
Turkish Journal of Chemistry
An electrolytic Copper Solution (ECS) was electrolyzed using platinum electrodes. Copper was obtained in solid form. In order to precipitate Cd(II), Bi(III), As(III), Sb(III) and the rest of the Cu(II) ions, H_2S gas was passed through the remaining solution. The remaining solution was evaporated to obtain metal sulphates. The sample containing metal sulphates was roasted at temperatures between 550 and 800°C. Cobalt, nickel and zinc in the solid sample remained in the form of metal sulphates, while the iron in the sample was converted into Fe_2O_3. This solid sample was dissolved in water and filtered in order to crystallize the …
Potentiometric Titrations Of Semicarbazone Derivatives 6-Keto 9-17 Mono Methyl Substituted Octadecanoic Acids In Non-Aqueous Media, Mustafa Yalçin, Süleyman Tanyolaç, İrfan Kizilcikli, Aydın Tavman
Potentiometric Titrations Of Semicarbazone Derivatives 6-Keto 9-17 Mono Methyl Substituted Octadecanoic Acids In Non-Aqueous Media, Mustafa Yalçin, Süleyman Tanyolaç, İrfan Kizilcikli, Aydın Tavman
Turkish Journal of Chemistry
The pK$_a$ values of 6-semicarbazone 9-17 monomethyl substituted octadecanoic acids were determined using the potentiometric titration method. 2-Propanol was used as the non-aqueous medium and tetrabutylammonium hydroxide (TBAH) as the titrant in the experiments. The contribution of semicarbazone and methyl groups to the pK$_a$ values of octadecanoic acids was investigated and evaluated. In addition, observations were made on the IR spectra of the compounds.
Effect Of Alkanols On The Micellar Behavior Of Chromium Laurate, Hüseyin Topallar, Yüksel Bayrak
Effect Of Alkanols On The Micellar Behavior Of Chromium Laurate, Hüseyin Topallar, Yüksel Bayrak
Turkish Journal of Chemistry
The critical micelle concentration, CMC, degree of dissociation, and dissociation constant of chromium laurate in alcohols (methanol, ethanol, propanol-1, butanol-1 and pentanol-1) were determined using conductometric measurements. The results show that chromium laurate behaves as simple electrolyte in dilute solutions below the CMC, and the conductance results can be explained according to Ostwald's formula and Debye-Huckel's theory of electrolytes.
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.
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 …
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.
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 And Characterization Of Amorphous-Liquid Crystalline Poly(Vinyl Ether) Block Copolymers, İ. Ersin Serhatli, Müge Serhatli
Synthesis And Characterization Of Amorphous-Liquid Crystalline Poly(Vinyl Ether) Block Copolymers, İ. Ersin Serhatli, Müge Serhatli
Turkish Journal of Chemistry
A new series of amorphous-liquid crystalline poly(vinyl ether) block copolymers was synthesized using living cationic polymerization and free-radical polymerization techniques. Vinyl ether monomer was polymerized using a trifluoromethane sulfonic acid and methyl triflouoromethanesulfonate/tetrahydrothiophene initiator system in dichloromethane at -18^oC, and quantitatively terminated with labile azo compounds in order to obtain poly(vinyl ether) with well-defined molecular weight and end groups. This polymer was used in a subsequent blocking step in which azo groups were decomposed at 80^oC in the presence of methyl methacrylate and styrene monomer. In both copolymers, blocks of different chemical composition were segregated in the solid and melt-phase …
Potential Utilization Of Fusel Oil: A Kinetic Approach For Production Of Fusel Oil Esters Through Chemical Reaction, Zeki Küçücük, Kadim Ceylan
Potential Utilization Of Fusel Oil: A Kinetic Approach For Production Of Fusel Oil Esters Through Chemical Reaction, Zeki Küçücük, Kadim Ceylan
Turkish Journal of Chemistry
Fusel oil is a by-product of the distillation of ethyl alcohol from the fermentation of molasses and contains mainly C3-C5 alcohols. Acetic acid and butyric acid esters of its major alcohol components have economic value as chemicals for flavor and fragrance manufacturing. This study presents some data regarding the uncatalyzed esterification of fusel oil with acetic acid, propionic acid and butyric acid. The reactions were carried out at two temperatures, i.e., $45^{\circ}$C and under the reflux conditions ($80-85^{\circ}$C). The composition of raw fusel oil and the reaction mixtures were determined by gas chromatography. The reaction rate constants for the formation …
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.
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 …
Further Studies On The Reaction Of Unsaturated Acids With O-Phenylenediamine And 4-Substituted O-Phenylenediamines In Acid Medium, Mashooda Hasan, Shagufta Munawar, Naeema Khan, Zahida Maqbool
Further Studies On The Reaction Of Unsaturated Acids With O-Phenylenediamine And 4-Substituted O-Phenylenediamines In Acid Medium, Mashooda Hasan, Shagufta Munawar, Naeema Khan, Zahida Maqbool
Turkish Journal of Chemistry
Condensation of methylcrotonic acid with 4-chloro-o-phenylenediamine in 4N HCl yielded 5-chloro-2-(1-isobutenyl)benzimidazole and 7-chloro-4, 4-dimethyl-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one. Methacrylic acid when condensed with o-phenylenediamine in 4N HCl yielded the already reported 3-methyl-1,2,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one and 2(2-propenyl)benzimidazole. Condensation of methacrylic acid with 4-chloro-o-phenylenediamine in 4N HCl yielded 5-chloro-2(2-propenyl)benzimidazole. The structures of all the purified compounds were confirmed with the help of mass and $^1$H NMR spectral analysis.
Potentiometric Investigation Of The Effects Of Several Substituents On The Basicity Of Benzilidene-O-Hydroxyaniline, Esma Kiliç, Orhan Atakol, E. Canel, Zehra Ali̇beşeoğlu, Turgut Gündüz, Fitnat Köseoğlu
Potentiometric Investigation Of The Effects Of Several Substituents On The Basicity Of Benzilidene-O-Hydroxyaniline, Esma Kiliç, Orhan Atakol, E. Canel, Zehra Ali̇beşeoğlu, Turgut Gündüz, Fitnat Köseoğlu
Turkish Journal of Chemistry
Chloro-, bromo-, iodo-, nitro-, methoxy- and hydroxy-substituted benzilidene-o-hydroxyaniline were prepared in order to investigate the effects of substituents on the basicity of benzilidene-o-hydroxyaniline. For each substituent, three isomers -- ortho, meta and para -- were synthesised. Schiff bases were titrated potentiometrically with perchloric acid in nitrobenzene solvent at $25^{\circ}$C. All compounds gave well-shaped titration curves, from which half-neutralisation potentials were calculated. The trend in the values of half-neutralisation potentials of Schiff bases were explained in terms of the nature of the substituents. The applicability of the Hammett equation to the effect of substituents in Schiff bases in nitrobenzene solvent was …