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Articles 2461 - 2490 of 2720
Full-Text Articles in Chemistry
Some Properties Of Cu, Zn-Superoxide Dismutase From Sheep Erythrocyte, Leman Tarhan, M. Nalan Tüzmen
Some Properties Of Cu, Zn-Superoxide Dismutase From Sheep Erythrocyte, Leman Tarhan, M. Nalan Tüzmen
Turkish Journal of Chemistry
Superoxide dismutase (SOD) was isolated from sheep erythrocyte. SOD activity was measured under the optimized assay conditions by observing the variations of autoxidation rate of 6-hydroxydopamine (6-OHDA). The enzyme was characterized as containing copper and zinc and was insensitive to chloroform-ethanol mixture but inhibited by cyanide and hydrogen peroxide. The activity variations and stability properties of sheep erythrocyte Cu, Zn-SOD were investigated under the optimized activity assay conditions by observing inhibition change at the autoxidation rate of 6-OHDA. The optimum pH and temperature of sheep erythrocyte Cu, Zn-SOD were found to be 9.4 and 30$^{\circ}$C respectively. The enzyme showed high …
Effect Of Non-Ionic Reagent Adsorption On Zeta Potential Of Fine Coal Particles, Zeki̇ Aktaş
Effect Of Non-Ionic Reagent Adsorption On Zeta Potential Of Fine Coal Particles, Zeki̇ Aktaş
Turkish Journal of Chemistry
The -5 \mum size fractions of two low rank British coals were used in zeta potential measurements. The electrophoretic behaviour was described by the Helmholtz-Smoluchowski equation. The non-ionic reagents used for the adsorption tests were of diacetone alcohol and 2-ethyl hexanol. Zeta potentials of both coals at various pHs were significantly different in the absence of the non-ionic reagents. Negligible variations were observed on the zeta potential curves of both coal particles in the presence of the non-ionic reagents used. It was concluded that the pH of coal particles in slurry is a principle parameter controlling the value of zeta …
An Efficient Synthesis Of (1 S , 2 R )-1-Amino-2-Indanol, A Key Intermediate Of Hiv Protease Inhibitor, Indinavir, Ayhan S. Demi̇r, Hi̇lal Aksoy-Cam, Nuretti̇n Camketen, Haluk Hamamci, Fatoş Doğanel
An Efficient Synthesis Of (1 S , 2 R )-1-Amino-2-Indanol, A Key Intermediate Of Hiv Protease Inhibitor, Indinavir, Ayhan S. Demi̇r, Hi̇lal Aksoy-Cam, Nuretti̇n Camketen, Haluk Hamamci, Fatoş Doğanel
Turkish Journal of Chemistry
(1S,2R)-1-amino-2-indanol, a key component of an HIV protease inhibitor is synthesized in four steps starting from indanone. The Mn(OAC)_3 mediated acetoxylation of indanone followed by fungus catalyzed hydrolysis of acetoxyindanone furnished optically pure \alpha-hydroxy indanone. Formation and enantioselective reduction of oxime ether of 2-hydroxyindanone afforded (1S, 2R)-1-amino-2-indanol in 97% {\it cis} selectivity.
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.
X-Ray Diffraction Study Of Heat-Treated Graphitized And Ungraphitized Carbon, Rizwan Hussain, Riaz Qadeer, Mahmood Ahmad, M. Saleem
X-Ray Diffraction Study Of Heat-Treated Graphitized And Ungraphitized Carbon, Rizwan Hussain, Riaz Qadeer, Mahmood Ahmad, M. Saleem
Turkish Journal of Chemistry
Heat treatment of graphitized and ungraphitized carbon samples was carried out in air and argon atmosphere from ambient temperature to 700$^{\circ}$C. The changes in degree of amorphousness, mean crystallite size and interlayer separations were studied employing x-ray diffraction. The results revealed an increase in crystallinity when graphitized carbon was heated to 100 ^oC and above. This enhanced degree of arrangement is indicative of the removal of residual impurities entrapped during the production processes. In ungraphitized carbon, the transition from amorphous to crystalline character was not observed upon heat treatment.
Heavy Metal Removal From Aquatic Systems By Northern Anatolian Smectites, Çi̇ğdem Arpa, Ridvan Say, Nuray Şatiroğlu, Sema Bektaş, Yuda Yürüm, Ömer Genç
Heavy Metal Removal From Aquatic Systems By Northern Anatolian Smectites, Çi̇ğdem Arpa, Ridvan Say, Nuray Şatiroğlu, Sema Bektaş, Yuda Yürüm, Ömer Genç
Turkish Journal of Chemistry
Competitive adsorption of the heavy metal ions Cu(II), Cd(II) and Pb(II) from aqueous media onto northern Anatolian smectites with a mean particle diameter of 200 $\mu$m, was investigated. The adsorption rate and capacity of the smectite for the selected heavy metal ions, containing different amounts of these ions (5-900 mg/L) at values ranging from pH 1.0 to 7.0 were studied. Very high adsorptions rates were observed at the beginning, and adsorption equilibria were then gradually achieved in about 30 minutes. The maximum adsorption of metal ions onto the smectite were found to be 41.46 mg Cd(II), 36.11 mg Pb(II) and …
The Effect Of Peripheral Circuits On The Total \Pi-Electron Energies Of Cyclacenes, Lemi̇ Türker
The Effect Of Peripheral Circuits On The Total \Pi-Electron Energies Of Cyclacenes, Lemi̇ Türker
Turkish Journal of Chemistry
Within the framework of the Hückel molecular orbital theory, certain linear models are developed to express the contribution of peripheral circuits of cyclacenes into their total \pi-electron energies, which explain why cyclacenes exhibit the cryptoannulenic behavior as their peripheral circuits which are annulenic in character.
Atmospheric Deposition Of Pb, Zn, Cu, And Cd In Amman, Jordan, Kamal A. Momani, Anwar G. Jiries, Qasem M. Jaradat
Atmospheric Deposition Of Pb, Zn, Cu, And Cd In Amman, Jordan, Kamal A. Momani, Anwar G. Jiries, Qasem M. Jaradat
Turkish Journal of Chemistry
Atmospheric samples were collected using a low-volume air sampler and dustfall containers during the summer of 1995 at different sites in the city of Amman, Jordan. The heavy metal contents in settleable particles (dustfall) as well as in air particulates (suspended) were analyzed by graphite furnace atomic absorbation spectrophotometry. The atmospheric concentrations of Zn, Cu, Pb, and Cd were 344, 170, 291, and 3.8 ng/m$^3$, respectively. The levels of these elements in the dustfall deposition were 505, 94, 74 and 3.1 $\mu$g/g, respectively. The fluxes and dry deposition velocities of these heavy metals were determined and compared with the findings …
Impedance Measurements Of Polyester-Coated Galvanised Mild Steel In 10xacid Rainwater After An Accelerated Wet-Dry Test, İlyas Dehri̇
Impedance Measurements Of Polyester-Coated Galvanised Mild Steel In 10xacid Rainwater After An Accelerated Wet-Dry Test, İlyas Dehri̇
Turkish Journal of Chemistry
The variation of defective polyester-coated performance with time in 10xacid rain solution was investigated using electrochemical impedance spectroscopy. Measurements were carried out on samples after an accelerated atmospheric corrosion test. The impedance diagrams (Nyquist plots) were simulated using the EQUIVCRT program which was elaborated by Boukamp and the semi-ellipse model which was developed by Erbil. It has been shown that the defective coating resistance changes with time for the samples subjected to acid rainwater. The corrosion rate of coated metal also changes with time.
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% …
Spectrophotometric Determination Of Selenium (Iv) Using Methdilazine Hydrochloride, Mahaveer B. Melwanki, Jaldappa Seetharamappa
Spectrophotometric Determination Of Selenium (Iv) Using Methdilazine Hydrochloride, Mahaveer B. Melwanki, Jaldappa Seetharamappa
Turkish Journal of Chemistry
Methdilazine hydrochloride is proposed as a selective and sensitive reagent for the spectrophotometric determination of selenium (IV). The reagent forms a red radical cation by selenimum (IV) in hydrochloric acid medium and exhibits an absorption maximum at 513 nm. Beer's law is valid over the concentration range 0.1-2.3 mg1^{-1} of selenium (IV). Sandell's sensitivity of the reaction is found to be 3.57 ng cm^{-2} and the molar extinction coefficient is 9.32 x 10^4 1 mol^{-1} cm^{-1} at 513 nm. The effects of acidity, reagent concentration, temperature and diverse ions upon the absorbance of the red species are critically assessed. The …
Electrothermal Atomic Absorption Spectrometric Determination Of Nickel After Its Flotation Enrichment By Iron(Iii) Hexamethylenedithiocarbamate, Trajce Stafilov, Gorica Pavlovska, Katarina Cundeva
Electrothermal Atomic Absorption Spectrometric Determination Of Nickel After Its Flotation Enrichment By Iron(Iii) Hexamethylenedithiocarbamate, Trajce Stafilov, Gorica Pavlovska, Katarina Cundeva
Turkish Journal of Chemistry
Abstract. Nanogram quantities of nickel were removed from 1 L samples of dilute aqueous solutions by coflotation. A mixture of hydrated iron(III) oxide (Fe_2O_3\( \cdot \)xH_2O) and iron(III) hexamethylene-dithiocarbamate (Fe(HMDTC)_3) served as collectors. After flotation separation from the mother liquor, the solid sublate containing nickel traces was dissolved and the analyte was determined by electrothermal atomic absorption spectrometry (ETAAS). All important parameters necessary for the successful collection of nickel were checked. The results of nickel ETAAS analysis in tap and spring waters were compared with inductively coupled plasma-atomic emis-sion spectrometric measurements (ICP-AES). The limit detection of nickel by the ETAAS …
Electroreduction Of Some Diazine And Triazine Pesticides At The Dropping Mercury Electrode, Petr Zuman, Marina Privman, Masami Shibata, Jiri Ludvik
Electroreduction Of Some Diazine And Triazine Pesticides At The Dropping Mercury Electrode, Petr Zuman, Marina Privman, Masami Shibata, Jiri Ludvik
Turkish Journal of Chemistry
Electroanalytical methods enable determination of electroactive species in nonhomogeneous systems, as limiting currents are little affected by the presence of solid and colloidal particles. An example of such applications of electrochemical methods are studies of binding of toxic substances, such as pesticides, on slightly soluble polymers, such as lignin. To successfully apply polarographic methods for following free pesticides in a slurry of lignin, it is first necessary in principle to elucidate the electrochemical processes involved. In aqueous buffered solutions the electron transfers, in which organic compounds participate, are in the majority of cases accompanied by chemical reactions. To elucidate the …
A Convenient Synthesis Of Some 4-(Alkylamino)-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones, Bahi̇tti̇n Kahveci̇, Aykut İki̇zler
A Convenient Synthesis Of Some 4-(Alkylamino)-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones, Bahi̇tti̇n Kahveci̇, Aykut İki̇zler
Turkish Journal of Chemistry
A series of 3-alkyl-4-(arylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 6-10,} was obtained from the reaction of the corresponding 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 1,} with the appropriate aldehydes. 3-alkyl-4-(alkylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones of type {\bfseries 11-16} were synthesized from the selective reduction of compounds {\bfseries 5-10} with NaBH$_{4}$ in diglyme or DMSO medium as a general and convenient method.
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 …
Hplc/Hydride Generation Aas Coupling For The Speciation Of Sb(Iii) And Sb(V) In Wastewaters, Nuray Şatiroğlu, Sema Bektaş, Ömer Genç, Haydar Hazel
Hplc/Hydride Generation Aas Coupling For The Speciation Of Sb(Iii) And Sb(V) In Wastewaters, Nuray Şatiroğlu, Sema Bektaş, Ömer Genç, Haydar Hazel
Turkish Journal of Chemistry
A comparative study was made with two HPLC columns of different lengths (PRP-X 100, 250 mm \( \times \) 4.1 mm id and PRP-X 100, 100 mm \( \times \) 4.1 mm id) coupled to HGAAS for the speciation of inorganic Sb(III) and Sb(V) species. The effects of eluent concentration and pH on the retention times of Sb species in both columns were investigated. The separation of Sb species was realized by using 50 mmol/L citrate solution at pH 4.0 as the eluent. The retention times were 2.0 min and 10.0 min in the 250 mm column, and 1.4 min …
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 …
Investigation Of The Influence Of Thiocarbamide In The Process Of Carbamide Deparaffinization, Sevi̇l Veli̇yeva
Investigation Of The Influence Of Thiocarbamide In The Process Of Carbamide Deparaffinization, Sevi̇l Veli̇yeva
Turkish Journal of Chemistry
The influence of thiocarbamide in the process of carbamide dewaxing was investigated. The dependence of separated paraffins on the quantity of thiocarbamide was examined experimentally. It was determined that the separation of paraffins becomes equal to zero when moles of carbamide and thiocarbamide in water-isopropyl alcohol solution are equal. The low-temperature qualities (the temperature of dimness and freezing) of dewaxed fuels were also examined. By using infrared spectroscopy methods, the compound of received paraffins was investigated.
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.
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 Of 4-Benzyl-1-Piperazineglyoxime And Its Use In The Spectrophotometric Determination Of Nickel, Mustafa Maci̇t, Hümeyra Bati, Beki̇r Bati
Synthesis Of 4-Benzyl-1-Piperazineglyoxime And Its Use In The Spectrophotometric Determination Of Nickel, Mustafa Maci̇t, Hümeyra Bati, Beki̇r Bati
Turkish Journal of Chemistry
A new reagent, 4-benzyl-1-piperazineglyoxime(BPGH_2), was synthesized and used for developing a simple and rapid extractive method for the spectrophotometric determination of nickel. This method is based on the selective extraction of nickel complex from aqueous solution into carbontetrachloride and the measurement of the absorption at 267 nm. The method was applied to the determination of nickel ion in some standard and practical samples.
Flavonol Glycosides From Consolida Armeniaca, Mustafa Küçüki̇slamoğlu, Nuretti̇n Yayli, Hasan Basri̇ Şentürk, Hasan Genç, Seçki̇n Özden
Flavonol Glycosides From Consolida Armeniaca, Mustafa Küçüki̇slamoğlu, Nuretti̇n Yayli, Hasan Basri̇ Şentürk, Hasan Genç, Seçki̇n Özden
Turkish Journal of Chemistry
Three known flavonol glycosides, i.e., kaempferol 3,7-O-\( \alpha \)-L-dirhamnopyranoside ({\bfseries 1}), kaempferol 3-O-\( \beta \)-D-glucopyranosyl-(1\( \ra \)2)-\( \alpha$-L-rhamnopyranoside-7-O-\( \alpha \)-L-rhamnopyranoside ({\bfseries 2}) and kaempferol 3-O-\( \alpha \)-L-rhamnopyranoside-7-O-\( \beta \)-D-glucopyranosyl-(1\( \ra \)2)-\( \alpha \)-L-rhamnopyranoside ({\bfseries 3}), were isolated for the first time from the flowers of {\itshape Consolida armeniaca}, and the structures of flavonol glycosides were deduced by high field 1D and 2D NMR and FAB-MS spectroscopies. The acetyl derivatives of {\bfseries 1-3} were also prepared ({\bfseries 1a, 2a, 3a}) and identified by NMR and positive FAB mass spectra.
High Fluorescence Emissions Of Some Natural Benzofurane Derivatives Isolated From Styrax Officinalis, Siddik İçli̇, Hüseyi̇n Anil, Bi̇rcan Di̇ndar, Özgen Alankuş Çalişkan, Yurdanur Yayla, Andrey O. Doroshenko, Serap Alp
High Fluorescence Emissions Of Some Natural Benzofurane Derivatives Isolated From Styrax Officinalis, Siddik İçli̇, Hüseyi̇n Anil, Bi̇rcan Di̇ndar, Özgen Alankuş Çalişkan, Yurdanur Yayla, Andrey O. Doroshenko, Serap Alp
Turkish Journal of Chemistry
The fluorescent properties of several natural benzofuran derivatives, egonols, isolated from {\it Styrax officinalis}, were determined. The studied egonol derivatives were found to be effective UV organic luminophores, with quantum yields of near to unity, \( \varphi_{f} \) = 0.92. The fluorescence quenching experiments with electron donor molecules of aniline, N,N-dimethylaniline and carbazolocarbazole, presented very high efficiency of quenching at above diffusion quenching rates of 4.5$\times$10\( ^{10} \), 2.1$\times$10\( ^\times \) and 5.6$\times$10\( ^{12} \) s\( ^{-1} \)mol\( ^{-1} \), respectively. A strong electron acceptor molecule, tetranitrofluorenone, presented quenching rate of 2.6$\times$10\( ^{11} \) s\( ^{-1} \)mol\( ^{-1} \). It …
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 …
Investigation Of The Synthesis Of Some Dehydroalanine Derivatives, Si̇bel Süzen, John Michael Williams
Investigation Of The Synthesis Of Some Dehydroalanine Derivatives, Si̇bel Süzen, John Michael Williams
Turkish Journal of Chemistry
Dehydroamino acids represent an important class of compound as they are key intermediates in unusual amino acid and in the design of peptides and are constituents of a variety of naturally occurring antibiotic and phytotoxic peptides. In view of the importance of proteins and peptides containing hydroxyamino acids and the problems associated with their synthesis and dehydration, an investigation was performed on model compounds in order to examine the difficulties of the dehydration reactions. The preparation and properties of the model dehydroalanine derivatives have been studied.
Zinc Determination In Pleural Fluid, Nazan Demi̇r, Yaşar Demi̇r, Ebubeki̇r Bakan, İrfan Küfrevi̇oğlu
Zinc Determination In Pleural Fluid, Nazan Demi̇r, Yaşar Demi̇r, Ebubeki̇r Bakan, İrfan Küfrevi̇oğlu
Turkish Journal of Chemistry
In this study, an enzymatic zinc determination method was applied to pleural fluid, the basis of which was the regaining of the activity of apo carbonic anhydrase by the zinc present in the sample. The method was used for pleural fluid zinc determination in order to show the application to body fluids other than serum. For this purpose, pleural fluids were obtained from 20 patients and zinc concentrations were determined. Carbonic anhydrase was purified by affinity chromatography from bovine erythrocytes. The zinc present in its structure was removed by dialysis against dipicolinic acid, resulting in apoenzyme obtained at a ratio …
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.
Determination Of Thermodynamic Parameters Of Some Complexes Of 9-Ethyl-3-Carbazolecarboxaldehyde 4-Phenyl-3-Thiosemicarbazone (Eccapt), E. Güler Akgemci̇, Tevfi̇k Atalay
Determination Of Thermodynamic Parameters Of Some Complexes Of 9-Ethyl-3-Carbazolecarboxaldehyde 4-Phenyl-3-Thiosemicarbazone (Eccapt), E. Güler Akgemci̇, Tevfi̇k Atalay
Turkish Journal of Chemistry
The complexes of Cu(II), Co(II), Zn(II), and Cd(II) with 9-ethyl-3-carbazolecarboxaldehyde 4-phenyl-3-thiosemicarbazone were synthesized and their stability constants were determined using a spectrophotometric method at different temperatures (25, 30, 35 and 40 \pm 0.1°C) and ionic strengths (0.05, 0.01 and 0.20 M KNO_3) in 50% (v/v) aqueous DMF. From these constants, the thermodynamic stability constants and thermodynamic parameters (\Delta G°, \Delta H° and \Delta S°) were calculated.
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.