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Apocarbonic Anhydrase-Enzymatic Determination Of Zinc In Fruit Juices, Ayşe Karagölge, Nazan Demi̇r, Yaşar Demi̇r, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

In this study, a new enzymatic method for determining trace amount of zinc was employed on ten different fruit juices. The basis of the enzymatic method is that apocarbonic anhydrase regains its activity in proportion to the Zn^{2+} existing in a solution. Thus, the more activated the enzyme is in the medium, the higher the Zn^{2+} concentration in the solution will be. For this purpose, bovine carbonic anhydrase was purified from erythrocyte hemolisate by affinity chromatography. The Zn^{2+} bound to the enzyme was removed by of the purified enzyme against the solution of pyridine-2-6-dicarboxylic acid. Thus 100\% purified enzyme was …

Investigation Of Hmo Spectra Of Hückel And Mobius Type Cyclacenes, Lemi Türker, Şakir Erkoç

Turkish Journal of Chemistry

The Hückel molecular orbital spectra (HMO) of Hückel- and Mobius-type cyclacenes having 3-15 benzenoid rings were investigated and it was found that certain eigenvalues are topologically invariant, whereas others exhibit topological periodicity. For example, Hückel-type cyclacenes having 2r (r: 2,3,4,...) benzenoid rings which possess nonbonding molecular orbitals (NBMO) and are thus expected to be open shell structures.

Investigation Of H-Bond On Fluorescence Changes In Benzene Derivations And Different Acceptor Systems, Nursel Acar Bayri, Özgül Koçak

Turkish Journal of Chemistry

In this study, benzene derivatives of phenol and naphtol were selected as donor systems and mixed with dioxane and TEA (triethylamine), which were chosen as acceptors. H-bond formation in the phenol-triethylamine binary system was investigated by both UV absorption and emission spectroscopies. The changes in the absorption and emission spectra by H-bond formation and the equilibrium of the H-bonded complexes were studied at both the ground and excited states. In addition, equilibrium constants at different temperatures and thermodynamic properties related to equilibrium (enthalpy, fere energy change and entropy values of H-bond formation) were calculated. A shift to longer wavelengths and …

Determination Of Ponceau 4r And Tartrazine In Various Food Samples By Derivative Spectrophotometric Methods, Sedat Sayar, Yüksel Özdemi̇r

Turkish Journal of Chemistry

Derivative spectrophotometric methods were originally developed for determining Ponceau 4R and Tartrazine in order to resolve their binary mixtures. The method permits the simultaneous determinations of these food colorants in various food samples. Recovery by derivative methods was nearly 100 \%.

Epr Spectroscopy Of Dog-Rose Polyphenoloxidase, Çiğdem Nuhoğlu, Fatih Ucun, Enise Ayyildiz, Y. Kemal Yoğurtçu, Halis Şaki̇roğlu, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

Polyphenoloxidase(PPO) of dog-rose fruit was extracted and purified through (NH\4)\2SO\4 precipitation and dialysis. The optimum conditions for this purpose, i.e., pH and temperature, were determined with 4-methylcatechol optimum pH and temperature and found to be pH 8.5 and 20\ci, respectively. The inhibition effect of ascorbic acid was investigated and the I_{50} value was found to be 1.57\times10^{-4} M. The activity of dog-rose PPO was investigated by electron paramagnetic resonance (EPR) at different pH levels and temperatures. The optimum conditions obtained from both spectrophotometry and EPR were compared.

Thermodynamics Of Dissociation Of Strontium, Barium And Nickel Caproates In Water, Hüseyin Topallar, Yüksel Bayrak, Mehmet İşcan

Turkish Journal of Chemistry

The critical micellar concentration (CMC) and thermodynamic parameters (heat \DeltaH_d, free energy \DeltaG_d, and entropy \DeltaS_d, of dissociation) of aqueous solutions of strontium, barium and nickel caproates were determined by conductivity measurements. A Kraus and Bray-type expression was used to evaluate molecular conductance at infinite dilution and theromdynamic parameters. The results confirm that CMC remains unaffected by temperature in the range of 25-55^{\circ}C, and show that the dissociation of soaps is an exothermic reaction and nonspontaneous.

Some Oxidation Reactions Of Isomeric Pyridinecarboxylic Acid Hydrazides, Rashid Iqbal, Samia Ebrahim, Muhammad Ziaulhaq

Turkish Journal of Chemistry

The oxidation reactions of the three isomeric pyridinecarboxylic acid hydrazides were studied using sodium metaperidoate, silver(I) oxide and potassium ferricyanide separately. Potassium ferricyanide emerged as an excellent reagent for preparation of 2-pyridinecarboxaldehyde and 3-pyridinecarboxaldehyde from the respective isomeric pyridinecarboxylic acid hydrazides. Oxidation with silver(I) oxide in each case yielded the corresponding 1,2-dipyridoylhydrazine, while sodium metaperiodate furnished different products with each isomeric pyridinecarboxylic acid hyrazide.

Effect Of Various Additives On The Hydration Of Perlite-Gypsum Plaster And Perlite-Portland Cement Pastes, Emin Erdem

Turkish Journal of Chemistry

Perlite is a volcanic glass which forms a light-weight cellular aggregate when ground and heated to about 1000\ci. It is used in the production of light-weight masonry blocks and concrete in the building industry as well as in insulation, fire protection, agriculture and pharmacology. In this study, the effects of admixtures such as lime, sodium citrate and various superplasticizers on the hydration of perlite-gypsum plaster, perlite-white Portland cement and perlite-blended Portland cement mixtures were investigated by measurement of flexural and compressive strengths and by DTA-TG. It was found that the addition of lime caused pozzolanic reactions and, consequently, increased strength …

The Synthesis Of Some Novel Chromans, M. Yalçinkaya, O. Bi̇lgi̇ç, S. Bi̇lgi̇ç

Turkish Journal of Chemistry

The inverse-electron demanded Diels-Alder reaction of 1-N,N-dimethylaminomethyl-2-naphthol (1) with substituted styrenes were investigated. With 2-, 3-, 4-methylstyrenes, 2-(2'-,3'- and 4'-methylphenyl)-benzo-5,6-chromans (5, 6 and 7) were obtained in 12, 18 and 53 \% yields respectively. With 2-, 3- and 4-chlorostyrenes, 2-(2'-, 3'- and 4'-chlorophenyl)-benzo-5,6-chromans (8,9 and 10) were obtained in 8, 20 and 33 \% yields respectively. With 4-vinyl-pyridine, 2-($4'-pyridyl)-benzo-5,6-chroman (11) was obtained in 48\% yield. In all pyrolysis no quinone-methide dimer (4) was encountered.

^1h Nmr, Infrared And Mass Spectrometry Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Muhammad Mazhar, Moazzam Hussain Bhatti, Sohail Mahmood, Abida Kalsoom

Turkish Journal of Chemistry

The di- and tri-organotin derivatives R\2SnL\2 and R\3SnL where R = CH\3, n--C\4H\9, C\6H\5, C\6H_{11} and C\6H\5CH\2 and L = 1-nitroso-2-naphthoxy were synthesized. These derivatives were characterized by elemental analysis, infrared, ^1H NMR and mass spectrometry.

Catalytically Active Intermediates In Photochemical Metathesis, Çetin Bozkurt, Yavuz İmamoğlu

Turkish Journal of Chemistry

The nature of the active species in photocatalytic metathesis reaction was investigated. The formation of Wittig-type addition products with benzaldehyde indicates that catalytically active carbene is the product of olefin and tungsten hexacarbonyl under reaction conditions.

Application Of Environmental Organic Petrology And Geochemistry To Fingerprint Organic Pollutants In The Recent Sediments Of Lake Ontario, Prasanta K. Mukhopadhyay, Michael A. Kruge, C.F. Michael Lewis

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Selected surface sediment samples (sediment depth 0-10 cm) collected in the Niagara basin (western Lake Ontario) were chosen for organic matter characterization using organic petrological and geochemical techniques normally reserved for the study of coal, petroleum source rock and crude oil. The study was performed to assess the effectiveness of these techniques in discriminating between natural and anthropogenic organic matter and to determine the extent of organic pollution of the lake sediments. The organic carbon contents of the samples vary from 1.5 to 3.5%, with upper layer (0-5 cm) samples have higher TOC values than those from the lower layer …

The Computational Study Of "Model" Pollutants In Clay Montmorillonite, Sung-Ho Park

Dissertations

No abstract provided.

Separation And Artificial Maturation Of Macerals From Type Ii Kerogen, Michael A. Kruge, Patrick Landais, David F. Bensley, B Artur Stankiewicz, Marcel Elie, Olivier Ruau

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Immature Type II kerogen (HI= 660 mg/g) from the Lower Toarcian of the Paris Basin was separated into an alginite concentrate (HI = 952 mg/g) and an amorphous organic matter (AOM) concentrate (HI = 573 mg/g) by density centrifugation. The flash pyrolyzate of the alginite is characterized by high relative concentrations of several series of n-alkanones and n-alkenones (including mid-chain alkyl ketones), in addition to n-alkanes, n-alk-1-enes and n-alkadienes. To our knowledge, this Toarcian alginite is the oldest example of marine organic matter whose pyrolyzate contains mid-chain alkanones in such high relative concentrations. In sharp …

Induced Acceleration Of Phosphine Exchange In Metal Carbonyls By Pendant Groups Of Coordinated Polyphosphines, Ping Ye

Masters Theses

The kinetics and thermodynamics of isomerization of (OC)₅CrPPh₂CH₂CH(PPh₂)₂ to its linkage isomer, (OC)₅CrPPh₂CH(PPh₂)CH₂PPh₂, in chloroform-d have been studied with ³¹P{¹H} NMR.

(OC)₅Cr[η¹-PPh₂CH₂CH(PPh₂)₂] ⇄ (OC)5Cr[η¹-PPh₂CH(PPh₂)CH₂PPh₂]

The equilibrium constants for the reaction are 3.60, 2.61, 2.04, and 1.67 at 10 °C, 25 °C, 40 °C, and 53 °C, respectively. The forward reaction becomes more favorable as the temperature …

An Expeditious Synthesis Of Β,Γ-Unsaturated Δ-Lactones: Useful Pharmacological Synthetic Intermediates, Li Xiong

Masters Theses

Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF₃-Et₂O or Et₂AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances.

Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions.

This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) …

Identification Of Organosulfur Compounds In Illinois Coal, Mandy N. Amin

Masters Theses

The goal of this research was to identify representative organosulfur compounds in Illinois coal which are removed by a mild, chemical desulfurization procedure. Pyridine was used to extract three raw Illinois coals. Coal with a significant amount of elemental sulfur was treated with 1:1 HCl/HF followed by lithium aluminum hydride before pyridine extraction. Pyridine soluble extracts were extracted with tetrahydrofuran. Nickel boride desulfurization was performed on the soluble extracts of the three coals. The before and after desulfurized THF soluble extracts were fractionated and purified by liquid chromatography and the eluents were anlyzed by gas chromatography/mass spectrometry to characterize the …

Constancy Of Bond Dissociation Energy Ratios For Ab₂/Ab Systems, Danyu Xu

Masters Theses

G2 and G2(MP2) theories have been used to study the bond dissociation energies D⁰_m of a series of AB₂, AB₂⁺, AB₂^-, AB, AB⁺ and AB^- systems. A total of fifty-four molecules and ions have been examined, for which B = O, S or Se and A = C, S, Ge, N⁺, P⁺, As⁺, B^-, Al^- or Ga^-. Each triatomic system has sixteen valence electrons and each diatomic system has ten valence electrons. Both triplet and singlet spin …

Semiclassical Approach To The Hydrogen-Exchange Reaction- Reactive And Transition-State Dynamics, Sophya V. Garashchuk, Grossmann Frank, David Tannor

Faculty Publications

Scattering matrix elements and symmetric transition-state resonances for the collinear H ₂ + H → H + H ₂ reaction are obtained using a time-dependent approach. The correlation function between reactant channel wavepackets and product channel wavepackets is used to determine the S-matrix elements. In a similar fashion, autocorrelation functions are used to extract the positions and widths of transition-state resonances. The time propagation of the wavepackets is performed by the improved semiclassical frozen Gaussian method of Herman and Kluk, which is an initial value, uniformly converged method. The agreement between the quantum and semiclassical results is far better …

Properties And Macromolecular Structure Of Unacetylated And Acetylated Nata De Coco, Ma. Assunta C. Cuyegkeng, Ma. Amy L. Dimalanta

Chemistry Faculty Publications

This study aims to gain more insight into the supramolecular structure of the cellulose in nata de coco, and to compare its ability to be modified with the known types of cellulose. The investigations were done using IR spectroscopy and thennal analysis. The IR spectra of microcrystalline cellulose were identical to cellulose spectra. However, those of dried nata de coco cellulose showed additional peaks that indicated a loss of inter- and intra-sheet hydrogen bonding, usually extensive in other cellulose forms where sheets are the prevalent secondary structures. This kind of structure would be consistent with the necessary framework for gel …

Construction Of Gold Micro-Bead Ultramicroelectrodes, Deon T. Miles, Andrew Knedlik, David O. Wipf

CAS Publications

A new way to construct small electrodes by the use of metal micro-beads is described. Gold beads of 1.5 to 3.0 mm diameter were used to construct inexpensive and disposable microelectrodes with overall structural diameters of £ 6 mm and electrode diameters of £ 5 mm. The voltammetric response of these electrodes is consistent with existing theory and the electrodes exhibited the sigmoidal waves expected at ultramicroelectrodes.

Synthesis Of An Organophosphorus Analog Of Acetylcholine, Darshan Mehta '97

Honors Projects

Acetylcholinesterase (AChE) is an important enzyme in our nervous system In normal nerve function, AChE catalyzes the hydrolysis of acetylcholine (ACh) into its respective components, choline and acetate. Recent interest has been focused on AChE because of its potential role in the pathology of neurodegenerative diseases such as Alzheimer's disease. Studies have revealed that the active site of AChE contains an esteratic and several hydrophobic/anionic subsites. AChE is inhibited by organophosphorus (OP) compounds like sarin and soman. As a result, OP compounds have been used to study the structure of AChE and the mechanism by which it catalyzes the hydrolysis …

Development Of A Tire Pyrolysis Process And Apparatus Using Steam Displacement Of The Combustible Atmosphere, Timothy Whitney Burrell

Dissertations and Theses @ UNI

It is the purpose of this research to convert a batch vacuum pyrolysis process into a pyrolytic process that operates at ambient air pressure with the capabilities of a continuous material flow operation. Further, it is important to optimize the conditions of the pyrolysis process so as to reduce costs of operation and to reasonably maximize products that have value. Steam will be used to displace the combustible atmosphere which enables ambient air pressure operation and elimination of need for inert carrier gasses or evacuation of the apparatus. The use of steam also allows water traps to be used as …

Some Remarks On Solid State Polymerization, George Adler

Turkish Journal of Chemistry

No abstract provided.

Dielectric Studies Of Various Olefin/So2 Copolmers, B. Baysal, Candan Erbi̇l, Paul L. Morganelli, W. H. Stockmayer

Turkish Journal of Chemistry

Dielectric constant and loss have been measured at low and high frequencies for several poly(1-olefin sulfones) as well as for the polysulfones of allybenzene and allyl cyclopentane. The low-frequency dispersion in allylbenzene due to helical sequences is weaker in benzene than in dioxane, and in both solvents is much lower than for the 1-olefin polymers. Solvent effects on the high frequency process are also reported, but yield no simple uniform picture.

Synthesis Characterization And Miscibility Of Polyvinyl Butyrals Of Varying Vinyl Alcohol Contents, Z. M. Zhou, D. J. David, W. J. Macknight, F. E. Karasz

Turkish Journal of Chemistry

Polyvinyl butyrals (PVB) of systematically varying vinyl alcohol content have been synthesized and characterized using wet chemistry, IR, DSC, and TGA. The miscibility of PVB-PVB blends was studied by DSC as a function of vinyl alcohol content and vinyl alcohol content differences between the respective blend components. These data were use to construct an isothermal miscibility map of PVB and to calculate the intramolecular interaction parameter \chi_{VA,VB}. The \chi_{VA,VB} was a function of the absolute level of the vinyl alcohol (VA) and vinyl butyral (VB) contents of the polymers. In addition, the thermal stability of polyvinyl butyral was found to …

Network Characterization Of Energetic Poly(Glycidyl-Azide), Mehmet S. Eroğlu, Olgun Güven

Turkish Journal of Chemistry

Energetic poly(glycidyl azide) (PGA) elastomers with different crosslink densities were prepared by varying the NCO/OH reactive-groups ratio from 0.8 to 1.0. In the preparation of the elastomers, PGA chains were end-liked with a mixture of hexamethylene diisocyanate (HMDI) and trimethylol propane (TMP) at a fixed TMP/PGA mole ratio. The number average molar mass between junction points of the network chains \overline{{\rm M}}_c was calculated using data obtained from swelling and uniaxial tensile tests and the results were compared. For the mechanical characterization of the networks, Mooney-Rivlin plots were prepared and the values of the constants 2C_1 and 2C_2 of PGA …

Synthesis Of The New Cation Exchange Resins Having Poly (Styrene-Caprolactone) Units, S. Savaşkan Yilmaz, Hulisi Özbayrak, Baki Hazer

Turkish Journal of Chemistry

The crosslinked polystyrene-polycaprolactone , PS-PCL-, block copolymers were prepared by the copolymerization of styrene and poly(caprolacton dimethylmethacrylate) (PCL-DM). The molecular weights of polycaprolactone, PCL, PCL-DM were 1250 and 2000. The swelling in H_2O or CHCl_3 of the sulfonated and unsulfonated block copolymers were determined under comparable conditions and investigated. The capacities of the obtained ion exchange resins were 1.31 and 1.10 meq/g.

Thermal Stabilities Of Hydroxyalkyl Terminated Polydimethylsiloxane Oligomers, İskender Yi̇lgor, Emel Yi̇lgor

Turkish Journal of Chemistry

The thermal stabilities of \alpha,\omega-hydroxypropyl, \alpha,\omega-hydroxybutyl \alpha,\omega-2-hydroxypentyl and \alpha,\omega-hydroxyhexyl terminated polydimethylsiloxane oligomers were investigated. Hydroxypropyl and hydroxybutyl terminated polydimethylsiloxane oligomers showed degradation upon heating through the loss of functional end groups, as determined by FTIR spectroscopy and gel permeation chromatography. \alpha,\omega-Hydroxyhexyl and \alpha,\omega-2-hydroxypentyl terminated polydimethylsiloxane oligomers were stable under similar conditions. The instability of the end groups is due to the backbiting of the terminal silicon in the PDMS by the primary hydroxyl oxygen, leading to the formation of 5-and 6-membered stable, heterocylic compounds. Loss of end groups also resulted in a dramatic increase in the molecular weights of the …

New Synthetic Approach For The Synthesis Of Liquid Crystalline Block And Graft Copolymers, Yeşim Hepuzer, İ. Ersin Serhatli, Yusuf Yağci

Turkish Journal of Chemistry

Liquid crystalline block and graft copolymers were synthesized according to the macroinitiator and macroinimer concept. For this purpose, side chain block copolymers (polytetrahydrofuran-b-polymethylmethacrylate) having liquid crystalline 4,4'- cyanobiphenyl blocks were prepared and characterized. Unlike the liquid-crystalline homopolymer with mesogenic units in the side chain, all block and graft copolymers showed a smectic A mesophase. The transition temperatures are hardly affected by the composition and molecular weight of the blolck copolymers.