Chemistry Commons^™

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 …

Novel Architectures Of Macromolecular Systems, Gerhard Wegner

Turkish Journal of Chemistry

An important thrust in modern macromolecular chemistry is to construct complex architectures either directly from monomer units, or to design macromolecules capable of forming a desired superstructure by self-organization. Chain-rigidity is an example of a structural principle leading to self organization depending on the aspect ratio of the molecular objects and their mutual interactions. These molecularly defined objects serve as the building blocks of systems for which ultrathin layers composed of hairy rod macromolecules (HRM) are an example. Depending on architectural details layered architectures of HRM are models for molecular nanocomposites, exhibit interesting optical, electrochemical, dielectric or barrier properties. They …

Antifungal Natural Products From Medicinal Plants Of Pakistan, Atta Rahman, M. I. Choudhary

Turkish Journal of Chemistry

A number of diseases in humans, animals, insects and plants are caused by pathogenic fungi. Several fungi also produce toxins in foods and can cause poisoning. Antifungal compounds are therefore important both for controlling serious fungal diseases of animals and plants, and for preserving food and other organic materials against attack by fungi. Our work on antifungal phytochemicals of medicinal plants has resulted in the isolation of a number of interesting compounds. The agar diffusion method was used to determine the antifungal activity of the pure isolates and extracts against a number of highly pathogenic fungi. The structures of the …

Analytical Applications Of Organic Conducting Polymer Electrodes, Nada F. Atta, George C. Russell, Z. Wang, N. Akmal, J.F. Rubinson, S.K. Lunsford, E. Karagözler, O. Y. Ataman, H. Zimmer, H.B. (Jr.) Mark, Ahmed Galal

Turkish Journal of Chemistry

Electrodes modified by he electrodeposition of conducting polymers were used for the detection and quantitative determination of some inorganic, organic, and biological molecules. Monomers used were five membered ring heterocycles or crown ethers and their derivatives. The polymer films were deposited on glassy carbon or platinum substrates. The resulting electrodes were used in the amperometric mode or in the potentiometric mode for flow injection and chromatographic analyses. The results showed that the proposed modified surface catalyzes the oxidation of organic and biological compounds. The detection of electroinactive inorganic anions, such as F^-, Cl^-, Br^-, NO_2^- and NO^-_3 was also possible …

Synthesis And Characterization Of Conducting Polymers And Their Composites, L. Toppare

Turkish Journal of Chemistry

Blends of conducting polymers polypyrrole and polyaniline, in the insulating host polymers, polybisphenol A carbonate, polyamide and polyamide have been prepared electrochemically. Composite homogeneity and a possible chemical interaction between the host matrices and the conducting polymers were searched. Several spectroscopic and thermal analyses of free standing films suggest such an interaction.

Dissociation Dynamics Of Small Carbon Clusters, Ersin Yurtsever, Nuran Elmaci

Turkish Journal of Chemistry

The dissociation dynamics of small carbon clusters is studied by classical trajectory analysis. A large number of initial conditions are chosen to analyze the effects of the energy, angular momentum and the initial geometry of the cluster. The dissociation times, decay rate constants, kinetic energy of the dissociating atoms and the geometrical structure of the remaining part of the clusters are computed from microcanonical sampling of the phase space. Distributions of these properties as well as the possibilities of various fragmentation channels are presented.

General Character Of Electrochaemically Adsorbed Cobalt On Smooth Platinum In Solutions Of Various Ph, Gülcemal Yildiz, Sadiq Kuluyev, Figen Kadirgan

Turkish Journal of Chemistry

The adsorption of cobalt adatoms on to a smooth platinum electrode at different potentials was studied by voltammetric methods. The amount of cobalt coverage was determined from the hydrogen region of the platinum electrode. The number of electrons per adatom species was calculated. The experiments were carried out in the pH interval between 0-3 in H_{2}SO_{4}-containing solutions.

A Computational Study On The Conformational Behaviour Of 1,1,2-Trihydroxyethane In Solution, Safiye Sağ Erdem, Tereza Varnali, Viktorya Avi̇yente

Turkish Journal of Chemistry

The conformational space of 1,1,2-trihydroxyethane were investigated with the PM3 method both in gas phase and in solution. Ab initio calculations at 6-31G level were also conformational equilibria in solution were studied and used to explain the behaviour of 2-hydroxycyclohexanone propylene and ethylene ketals.

Complexes Of Zn(Ii), Pd(Ii), Hg(Ii), Pb(Ii), Cu(I), Ag(I) And Tl(I) With 4-Amino-5-Mercapto-3-(O-Tolyloxymethyl)-1,2,4-Triazole, B. Narayana, M. R. Gajendragad

Turkish Journal of Chemistry

The synthesis and characterization of complexes of Zn(II), Pd(II), Cd(II), Hg(II), Pb(II), Cu(I), Ag(I), and Tl(I) with 4-amino-5-mercapto-3-(o- tolyloxymethyl)-1,2,4-triazole are described. Based on analytical results, electronic and infrared spectral data and magnetic susceptibility measurements suitable structures have been proposed.

Topological Constraints On Hmo Hetereoatom Parameters, Lemi Türker

Turkish Journal of Chemistry

Within the Hückel molecular orbital framework, the effect of topological factors on the selection of heteroatom parameters for heteroconjugated systems is discussed.

Factors Influencing The Angle Of Total Ii-Electron Energies Of Alternant Hydrocarbons, Lemi Türker

Turkish Journal of Chemistry

Within the framework of the Hückel molecular orbital theory, the topological factors affecting the angle of total \pi-electron energies of alternant hydrocarbons were investigated.

Controlled Release Of Aldicarb From Carboxymethylcellulese Microcapsules, M. Yakup Arica, Mustafa Yi̇ği̇toğlu, Mustafa Lale, Fatma N. Kök, Vasıf Hasirci

Turkish Journal of Chemistry

Sodium carboxymethyl cellulose was converted into microspheres by crosslinking with aluminum chloride. Various microsheres with different amounts of crosslinker, biopolymer of various concentrations and molecular weights, and with different pesticide (Aldicarb) contents and pesticide to polymer ratios were prepared. The pesticide encapsulation efficiencies and aldicarb release kinetics of the resultant microcapsules were investigated. It was possible to modify the release behaviour by varying the above parameters and to have drug release with half-lives longer than 100 hours in aqueous media. The release kinetics were described by first order and zero order kinetics.

Spectrophotometric Determination Of The Pk_A Values Of Some Aminoacid Complexes Of Pentacyanoferrate(Ii) And Pentacyanoruthenate(Ii), Yakup Baran, Şebnem Baran, N. Kemal Tunali

Turkish Journal of Chemistry

The syntheses, pK_a and spectrospcopic characterization of [Fe(CN)_5(H_2O)]^{-3} and [Ru(CN)_5(H_2O)]^{-3} complexes of alanine(Ala), glycine(Gly), valine(Val), lysine(Lys), arginine(Arg) and cysteine(Cys) complexes were investigated in aqueous solution. The spectra of the complexes containing amino acid ligands were similar to that of [Fe(CN)_5(NH_3)]^{-3}. The pK_a values of the complexes were measured by spectrophotometric titration at 22^{\circ}C and \mu =0.100 M(NaClO_4).

Carbonic Anhydrase From Nicotiana Tabacum Leaves, Nazan Demi̇r, Yaşar Demi̇r

Turkish Journal of Chemistry

In this study, carbonic anhydrase (CA: carbonate hydrolyase; E.C.4.2.1.1) was purified from adult {\it Nicotiana tabacum} leaves and studied biochemically. The enzyme was purified twice times by using (NH$_4)_2SO_4 precipation and DEAE-cellulose column chromatography, and its activity was determined for two different substrates (CO_2 and p-nitrophenyl acetate). The enzyme obtained from the ion exchange column was purified 40.7 fold and the purity was controlled by 3\%-10\% discontinuous SDS-PAGE. The pH of the purified enzyme varied between 6.0 and 7.2, the optimum being 6.9. V_{max} and K_m values were calculated with p-nitrophenyl acetate (0.1524 mM, 0.5446 mM, respectively) as substrate. The …

Electron Spin Resonance Studies On Cobalt Carbonic Anhydrase-Substrate Complexes, Çigdem Nuhoğlu, Nazan Demi̇r, Barbaros Nalbantoğlu, Ö. İrfan Küfrevi̇oğlu, Y. Kemal Yoğurtçu, Hasan Özdemi̇r, Enise Ayyildiz

Turkish Journal of Chemistry

The native zinc atom of bovine erythrocyte carbonic anhydrase purified by affinity choromatography was removed by dialysis against pyridine 2,6-dicarboxylic acid. Cobalt carbonic anhydrase was prepared from the zinc-free apoenzyme. The binding conditions of CO_2 and p-nitrophenylacetate to cobalt carbonic anhydrase were investigated by electron spin resonance at different pH levels.

A Novel Glycosidicly Linked Piperidine Alkaloid From Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci

Turkish Journal of Chemistry

The structure of a novel piperidine type alkaloid from {\it Cyclamen coum} was established as 2-\beta-D-glycopyranosyl-2-undecil-3,5-dihydroxy-6-carboxypiperidine, {\bf 1,} whose structure has been deduced from spectral data.

A Quantum-Chemical Investigation On 3-(4h-1,2,4-Triazol-4-Yl)-1h-1,2,4-Triazole, Rıza Abbasoğlu, Necdet Saltek, A. Aykut İki̇zler

Turkish Journal of Chemistry

The molecular conformations and electronic properties of the 3-(4H-1,2,4-triazol-4-yl)-1H-1,2,4-triazole molecule containing various reaction centers were investigated by the semiempirical methods MNDO, AM1 and PM3. The most stable conformation of the molecule was determined to be the planar conformation. The total energies, heats of formation, dipole moments, rotational barriers, geometric parameters, ionization potentials, full atomic charges, energies of frontier molecular orbitals (E_{HOMO} and E_{LUMO}) and their electron densities were calculated and discussed. In order to determine the protonation sites of the 3,4'-bitriazole system, the molecular electrostatic potential (MESP) of the molecule has also been calculated. The conformations and electronic properties of …

Influence Of Some Crosslinkers On The Swelling Of Acrylamide-Crotonic Acid Hydrogels, Erdener Karadağ, Dursun Saraydin, Olgun Güven

Turkish Journal of Chemistry

Acrylamide-crotonic acid hydrogels in the form of rods are prepared by \gamma-irradiation of quaternary mixtures of acrylamide-crotonic acid-crosslinker-water with 2.6 and 5.2 kGy \gamma-rays. The influence of the applied dose, the relative content of crotonic acid and crosslinkers such as ethylene glycol dimethacrylate, 1.4 butanediol dimethacrylate and N,N' methylenebisacrylamide on the swelling properties of the gel, the diffusional behaviour of water, the diffusion coefficient, and the network parameters of hydrogel systems are examined. Acrylamide-crotonic acid hydrogels containing various crosslinkers had a maximum swelling in the range 240-850 \%. Water diffusion to hydrogels was non-Fickian. The diffusion coefficients varied between 4.6 …

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 \%.

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.

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.

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.

Some Remarks On Solid State Polymerization, George Adler

Turkish Journal of Chemistry

No abstract provided.

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.