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Full-Text Articles in Physical Sciences and Mathematics

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 Jan 2000

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 Jan 2000

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.


Determination Of Thermodynamic Parameters Of Some Complexes Of 9-Ethyl-3-Carbazolecarboxaldehyde 4-Phenyl-3-Thiosemicarbazone (Eccapt), E. Güler Akgemci̇, Tevfi̇k Atalay Jan 2000

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.


Specific Determination Of Hydrogen Peroxide With A Catalase Biosensor Based On Mercury Thin Film Electrodes, F. Ni̇l Ertaş, Suna Ti̇mur, Erol Akyilmaz, Erhan Di̇nçkaya Jan 2000

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.


Preparation Of Optically Active Amino Acid Derivatives Of Some Methylated 5-Amino-Azaheterocycles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus, Shazia Munir Jan 2000

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.


X-Ray Diffraction Study Of Heat-Treated Graphitized And Ungraphitized Carbon, Rizwan Hussain, Riaz Qadeer, Mahmood Ahmad, M. Saleem Jan 2000

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.


Flavonol Glycosides From Consolida Armeniaca, Mustafa Küçüki̇slamoğlu, Nuretti̇n Yayli, Hasan Basri̇ Şentürk, Hasan Genç, Seçki̇n Özden Jan 2000

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 Jan 2000

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 …


The Effect Of Peripheral Circuits On The Total \Pi-Electron Energies Of Cyclacenes, Lemi̇ Türker Jan 2000

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.


Modification Of Polyester And Polyamide Fabrics By Different In Situ Plasma Polymerization Methods, T. Öktem, N. Seventeki̇n, H. Ayhan, Erhan Pi̇şki̇n Jan 2000

Modification Of Polyester And Polyamide Fabrics By Different In Situ Plasma Polymerization Methods, T. Öktem, N. Seventeki̇n, H. Ayhan, Erhan Pi̇şki̇n

Turkish Journal of Chemistry

In order to increase the hydrophilicities, and therefore to impart soil resistance and to improve dyeability, poly(ethylene terephthalate) (PET) and polyamide (PAm) fabrics were treated in low-temperature plasmas. Five different modification types were applied. Fabrics were directly treated in acrylic acid, water, air, O_2 and argon plasma. The plasma conditions (i.e., exposure time and discharge power) were changed to control the extent of plasma surface modification. Wettability, soil resistance and dyebility of PET fabrics were significantly improved by this method. More hydrophilic surfaces were created by all the methods.


Polarographic Determination Of Fluvoxamine Maleate In Tablets, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Sidika Sungur, Şule Aycan Jan 2000

Polarographic Determination Of Fluvoxamine Maleate In Tablets, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Sidika Sungur, Şule Aycan

Turkish Journal of Chemistry

The differential pulse polarographic (DPP) method was developed for the determination of fluvoxamine maleate (I). At pH = 3. 7, (I) give a peak at - 0. 73 V in aqueous solution. The developed method was applied to the assay of the drug substance in commercial tablet formulations. The results were statistically compared with those obtained by reference methods (HPLC and direct current polarographic method) using t- and F- tests at 95 % confidence level.


Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz Jan 2000

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 …


Zinc Determination In Pleural Fluid, Nazan Demi̇r, Yaşar Demi̇r, Ebubeki̇r Bakan, İrfan Küfrevi̇oğlu Jan 2000

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 …


X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep Jan 2000

X-Ray Powder Diffraction And Ir Study Of Calcium Borophosphate Cabpo_5, A. Baykal, G. Gözel, Meral Kizilyalli, M. Toprak, R. Kniep

Turkish Journal of Chemistry

In this study, CaBPO_5 was synthesized by different solid state reactions than reported before and its X-ray powder diffraction and IR data were reported. In one of these solid state reactions BPO_4 was used as a phosphating agent. The examination of the X-ray powder diffraction data showed that this compound crystallized in a hexagonal system and the refined unit cell parameters were a = 6.684, c = 6.616(2) \AA, with Z=3 as reported before. From the observed reflections, the space group was determined as P3_121, and its density was found to be 3.15 g/cc. The X-ray powder diffraction and IR …


All Solid-State Contact Lead(Ii) Ion-Selective Pvc Membrane Electrode Using Dimethylene Bis(4-Methylpiperidinedithiocarbamate) Neutral Ionophore, İbrahi̇m Işildak Jan 2000

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 Jan 2000

High-Performance Liquid Chromatographic Determination Of Oxytetracycline Residue In Cured Meat Products, Hami̇de Z. Şenyuva, Tuncel Özden, Deni̇z Yurtsever Sarica

Turkish Journal of Chemistry

The development of a sensitive automated method for residue control of oxytetracycline (OTC) in cured meat (soudjouk) is described. The principle steps involve the extraction of OTC from cured meat in the presence of citric acid with nitric acid, methanol and de-ionized water, and then the determination by HPLC. In HPLC, Hypersil BDC C18 column was used and OTC was separated at 24 ^{o}C using a mobile phase of H_2O (pH=2.10 with H_2SO_4): ACN (85:15, v/v) at a flow rate of 1.5 ml/min. A variable wavelength detector was set at 360 nm. The detection limit of the method was calculated …


Adsorption Of Some Heavy Metal Ions From Aqueous Solution By Activated Carbon And Comparison Of Percent Adsorption Results Of Activated Carbon With Those Of Some Other Adsorbents, İlhan Uzun, Fuat Güzel Jan 2000

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 …


A Study On N-Hydroxyamide Ethoxycarbonylhydrazones, A. Aykut İki̇zler, Ahmet Demi̇rbaş, Rza Abbasoğlu Jan 2000

A Study On N-Hydroxyamide Ethoxycarbonylhydrazones, A. Aykut İki̇zler, Ahmet Demi̇rbaş, Rza Abbasoğlu

Turkish Journal of Chemistry

The structures and electronic properties of N-hydroxyamide ethoxycarbonylhydrazones were investigated by a quantum-chemical method AMl. The total energies, heats of formation, dipol moments, ionization potentials, proton affinities and energies of frontier molecular orbitals (E_{HOMO} and E_{LUMO}) were calculated and discussed. The stabilities of the tautomeric forms and of E and Z isomers for these compounds were determined. The complex forming ability of these compounds with metal cations was also studied. The geometry and electronic properties of the complexes formed by N-hydroxyacetamide ethoxycarbonylhydrazone with Ni^{2+} and Cu^{2+} were investigated using ZINDO/1 semiempirical method. Moreover, these complexes were synthesized and identified.


The Measurement Of Surface Areas Of Some Silicates By Solution Adsorption, Oğuz İnel, Fatma Tümsek Jan 2000

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 …


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 Jan 2000

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 Jan 2000

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 Jan 2000

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 Jan 2000

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 Of 4-Benzyl-1-Piperazineglyoxime And Its Use In The Spectrophotometric Determination Of Nickel, Mustafa Maci̇t, Hümeyra Bati, Beki̇r Bati Jan 2000

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.


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 Jan 2000

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 …


Some Properties Of Cu, Zn-Superoxide Dismutase From Sheep Erythrocyte, Leman Tarhan, M. Nalan Tüzmen Jan 2000

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 Jan 2000

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 …


Magnitudes Of Back Diffusion During Long-Term Diffusive Sampling Of Volatile Organic Compounds Using Carbotrap And Chromosorb 106, Naci̇ye Kiliç, James A. Ballantine Jan 2000

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 …


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 Jan 2000

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 Jan 2000

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.