Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

2009

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 481 - 510 of 823

Full-Text Articles in Chemistry

Ua94/6/1 Student / Alumni Personal Papers Western Kentucky University Small Collections, Wku Archives Jan 2009

Ua94/6/1 Student / Alumni Personal Papers Western Kentucky University Small Collections, Wku Archives

WKU Archives Collection Inventories

Small collections of personal papers and oral histories relating to the Western Kentucky University.

Go to article

Nos-Based Biopolymers: Towards Novel Thromboresistant No-Release Materials, Charbel Abou Diwan Jan 2009

Nos-Based Biopolymers: Towards Novel Thromboresistant No-Release Materials, Charbel Abou Diwan

ETD Archive

Nitric Oxide releasing biopolymers have the potential to prolong vascular graft and stent potency without adverse systemic vasodilation. It was reported in literature that eNOS-overexpressing endothelial cell seeding of synthetic small diameter vascular grafts decreased human platelet aggregation by 46 and bovine aortic smooth muscle cell proliferation by 67.2 in vitro. We hypothesized that incorporating the enzyme nitric oxide synthase (NOS) in biocompatible polymeric matrix will provide a source of NO that utilizes endogenous compounds to maintain an unlimited supply of NO. To test this hypothesis, we have incorporated the enzyme nitric oxide synthase into a polyethyleneimine film using a …

Go to article

Cofactor Control Of A Vital Enzymatic Reaction;The Effect Of Factor Va On Thrombin Formation During Blood Coagulation, Jamila Hirbawi Jan 2009

Cofactor Control Of A Vital Enzymatic Reaction;The Effect Of Factor Va On Thrombin Formation During Blood Coagulation, Jamila Hirbawi

ETD Archive

The LONG-TERM goal of our research is to study and analyze the structure and function of the factor V molecule in order to understand its regulatory effects on the natural process of hemostasis and its role in the life-threatening development of deep venous thrombosis. The SHORT-TERM goal of our research is to identify the amino acid residue(s) of factor V that interact with prothrombin during the assembly and function of the prothrombinase complex in order to fully understand its particular role in maintaining the integrity of the blood coagulation cascade. The final goal of the coagulation cascade is the formation …

Go to article

Hemoprotein-Mediated Activation Of Nitroalkanes, Ling Li Jan 2009

Hemoprotein-Mediated Activation Of Nitroalkanes, Ling Li

ETD Archive

Chemicals and drugs are known to be metabolized mostly by Cytochrome P450 xenobiotic metabolizing enzymes. However, the detailed mechanism of nitro-compounds metabolism is still unclear. The activation of nitro-xenobiotics by heme-P450 enzymes is a potential explanation for the origin of nitro-compound carcinogenesis. Investigating the interaction of simple nitro-compounds with redox activity of heme enzymes is therefore critical to explore the mechanism and products of activation. In this study, multiple analytical methods and instrumentations are employed and graphic and simulation software such as Origin┬« and Digisim┬« are utilized to quantitatively derive parameters from experimental raw data. This study shows that myoglobin, …

Go to article

Development Of A Novel Gradient Chromatofocusing Tandem Mass Spectometry Technique For The Determination Of Cationic Compounds In Biofluids;Identification Of Caspace 3 Cleavage Sites Of Nhe-1 By High Performance Liquid Chromatography- Mass Spectrometry, Jianhua Tang Jan 2009

Development Of A Novel Gradient Chromatofocusing Tandem Mass Spectometry Technique For The Determination Of Cationic Compounds In Biofluids;Identification Of Caspace 3 Cleavage Sites Of Nhe-1 By High Performance Liquid Chromatography- Mass Spectrometry, Jianhua Tang

ETD Archive

In Part I, work was done to develop a novel gradient chromatofocusing liquid chromatography-tandem mass spectrometry (MS/MS) technique for the determination of ionic compounds in biological matrix. The analysis of ionic compounds poses a great challenge to current LC-MS techniques, due to the fact that there is little or no retention. These ionic compounds are eluted at almost the same time as biological matrix, which is normally directed to waste prior to connecting to the mass spectrometer. A review of current LC-MS techniques for ionic compounds is given in Chapter 1. They all have advantages and disadvantages. To retain and …

Go to article

Plasma Biomarkers For Age-Related Macular Degeneration, Jiaqian Ni Jan 2009

Plasma Biomarkers For Age-Related Macular Degeneration, Jiaqian Ni

ETD Archive

No abstract provided.

Go to article

Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth(Iii) Bromide Catalyzed Synthesis Of Substituted Tetrahydroquinoline Derivatives, Ram Mohan, Jamie Rogers, Justin Ernat, Herbie Yung Jan 2009

Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth(Iii) Bromide Catalyzed Synthesis Of Substituted Tetrahydroquinoline Derivatives, Ram Mohan, Jamie Rogers, Justin Ernat, Herbie Yung

Scholarship

The bismuth bromide catalyzed synthesis of a range of substituted tetrahydroquinoline derivatives via a three component coupling reaction between substituted anilines and enol ethers is reported. Bismuth compounds are attractive for use as catalysts because of their remarkably low toxicity. Bismuth bromide is relatively inexpensive and easy to handle, and hence preferable to other corrosive catalysts previously used for synthesis of tetrahydroquinoline derivatives.

Go to article

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat Jan 2009

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat

Articles

No abstract provided.

Go to article

Allosteric Regulation Of The Primase (Dnag) Activity By The Clamp-Loader (Τ) In Vitro, Kiran Chintakayala, Cristina Machón, Anna Haroniti, Marilyn A. Larson, Steven H. Hinrichs, Mark A. Griep, Panos Soultanas Jan 2009

Allosteric Regulation Of The Primase (Dnag) Activity By The Clamp-Loader (Τ) In Vitro, Kiran Chintakayala, Cristina Machón, Anna Haroniti, Marilyn A. Larson, Steven H. Hinrichs, Mark A. Griep, Panos Soultanas

Mark A. Griep Publications

During DNA replication the helicase (DnaB) recruits the primase (DnaG) in the replisome to initiate the polymerization of new DNA strands. DnaB is attached to the τ subunit of the clamp-loader that loads the β clamp and interconnects the core polymerases on the leading and lagging strands. The τ–DnaB−DnaG ternary complex is at the heart of the replisome and its function is likely to be modulated by a complex network of allosteric interactions. Using a stable ternary complex comprising the primase and helicase from Geobacillus stearothermophilus and the τ subunit of the clamp-loader from Bacillus subtilis we show that changes …

Go to article

Steel Hull Corrosion Of Uss Arizona With Applications To Submerged Resources, D. L. Johnson, D. J. Medlin, M. A. Russell, D. L. Conlin, L. E. Murphy, J. D. Carr Jan 2009

Steel Hull Corrosion Of Uss Arizona With Applications To Submerged Resources, D. L. Johnson, D. J. Medlin, M. A. Russell, D. L. Conlin, L. E. Murphy, J. D. Carr

Department of Chemistry: Faculty Publications

The USS Arizona Preservation project is a multi-year, interdisciplinary and cumulative effort with each discipline contributing to basic research required to make informed management decisions for long-term preservation. Three significant issues include: (1) USS Arizona is a grave site for 900 or more Navy and Marine personal lost with the USS Arizona when Japanese forces attacked Pearl Harbor on Dec 7, 1941. (2) Minimizing environmental hazard from a potential fuel oil release of an estimated 500,000 gallons remaining in fuel bunkers or compartment overheads. A cross section view of the ship and bunkers before and after the attack is shown …

Go to article

Quantum Mechanical/Molecular Mechanical/Continuum Style Solvation Model: Linear Response Theory, Variational Treatment, And Nuclear Gradients, Hui Li Jan 2009

Quantum Mechanical/Molecular Mechanical/Continuum Style Solvation Model: Linear Response Theory, Variational Treatment, And Nuclear Gradients, Hui Li

Department of Chemistry: Faculty Publications

Linear response and variational treatment are formulated for Hartree–Fock (HF) and Kohn–Sham density functional theory (DFT) methods and combined discrete-continuum solvation models that incorporate self-consistently induced dipoles and charges. Due to the variational treatment, analytic nuclear gradients can be evaluated efficiently for these discrete and continuum solvation models. The forces and torques on the induced point dipoles and point charges can be evaluated using simple electrostatic formulas as for permanent point dipoles and point charges, in accordance with the electrostatic nature of these methods. Implementation and tests using the effective fragment potential (EFP, a polarizable force field) method and the …

Go to article

Tuning The Electronic Properties Of The Golden Buckyball By Endohedral Doping: M@Au16− (M=Ag,Zn, In), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2009

Tuning The Electronic Properties Of The Golden Buckyball By Endohedral Doping: M@Au16− (M=Ag,Zn, In), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

The golden Au16- cage is doped systematically with an external atom of different valence electrons: Ag, Zn, and In. The electronic and structural properties of the doped clusters, MAu16- (M =Ag,Zn, In), are investigated by photoelectron spectroscopy and theoretical calculations. It is observed that the characteristic spectral features of 16-, reflecting its near tetrahedral (Td) symmetry, are retained in the photoelectron spectra of MAu16-, suggesting endohedral structures with little distortion from the parent Au16- cage for the doped clusters. Density functional calculations show that …

Go to article

Magnetic Doping Of The Golden Cage Cluster M@Au16− (M=Fe,Co,Ni), Lei-Ming Wang, Jaeil Bai, Anne Lechtken, Wei Huang, Detlef Schooss, Manfred Kappes, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2009

Magnetic Doping Of The Golden Cage Cluster M@Au16− (M=Fe,Co,Ni), Lei-Ming Wang, Jaeil Bai, Anne Lechtken, Wei Huang, Detlef Schooss, Manfred Kappes, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

Structural, electronic, and magnetic properties of the golden cage doped with a transition-metal atom, MAu16- (M =Fe,Co,Ni), are investigated using trapped ion electron diffraction, photoelectron spectroscopy, and density-functional theory. The best agreement to experiment is obtained for endohedral M@Au16- structures but with considerable distortions to the parent Au16- cage. Fe@Au16- and Co@Au16- are found to have similar structures with C2 symmetry while a C1 structure is obtained for Ni@Au16-. The 4s electrons are observed to transfer to the Au16 cage, whereas atomiclike …

Go to article

Singing The Moly Blues: The Direct Use Of Molybdenum Clusters As A Precursor To The Development Of Molybdenum Blue Glazes, Margaret Fiedler Jan 2009

Singing The Moly Blues: The Direct Use Of Molybdenum Clusters As A Precursor To The Development Of Molybdenum Blue Glazes, Margaret Fiedler

Undergraduate Review

Cobalt is currently the most commonly used blue colorant for ceramic glazes, however due to its toxicity in powder form there is a need for an alternative. Molybdenum, more specifically molybdenum oxide, is one alternative that has shown promise. This research is aimed at the direct incorporation of reduced molybdenum clusters into the glaze matrix. Two compounds have been synthesized that exhibit an intense blue color, Na15[MoVI126MoV28O457H14(H2O)70]0.5-[MoVI124MoV28O427H14(H2O)68]0.5 …

Go to article

Radiative Recombination Of Spatially Extended Excitons In (Znse/Cds)/Cds Heterostructured Nanorods, Nishshanka N. Hewa-Kasakarage, Maria Kirsanova, Alexander Nemchinov, Nickolas Schmall, Patrick Z. El-Khoury, Alexander N. Tarnovsky, Mikhail Zamkov Jan 2009

Radiative Recombination Of Spatially Extended Excitons In (Znse/Cds)/Cds Heterostructured Nanorods, Nishshanka N. Hewa-Kasakarage, Maria Kirsanova, Alexander Nemchinov, Nickolas Schmall, Patrick Z. El-Khoury, Alexander N. Tarnovsky, Mikhail Zamkov

Chemistry Faculty Publications

We report on organometallic synthesis of luminescent (ZnSe/CdS)/CdS semiconductor heterostructured nanorods (hetero-NRs) that produce an efficient spatial separation of carriers along the main axis of the structure (type II carrier localization). Nanorods were fabricated using a seeded-type approach by nucleating the growth of 20-100 nm CdS extensions at [000 +/- 1] facets of wurtzite ZnSe/CdS core/shell nanocrystals. The difference in growth rates of CdS in each of the two directions ensures that the position of ZnSe/CdS seeds in the final structure is offset from the center of hetero-NRs, resulting in a spatially asymmetric distribution of carrier wave functions along the …

Go to article

Anion Binding Modes In Meso-Substituted Hexapyrrolic Calix[4]Pyrrole Isomers, Kai-Chi Chang, Tsuyoshi Minami, Petr Koutnik, Pavel Y. Savechenkov, Yuanli Liu, Pavel Anzenbacher Jr. Jan 2009

Anion Binding Modes In Meso-Substituted Hexapyrrolic Calix[4]Pyrrole Isomers, Kai-Chi Chang, Tsuyoshi Minami, Petr Koutnik, Pavel Y. Savechenkov, Yuanli Liu, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

We report on the synthesis of a new receptor for anions, meso-substituted hexapyrrolic calix[4]pyrrole 1. The calix[4]pyrrole's core features two additional pyrrole side-arms suspended above or below the calix[4]pyrrole core. This hexapyrrolic calix[4]pyrrole 1 is formed as cis- and trans-configurational isomers, the structures of which have been determined by single crystal X-ray diffraction. The anion binding experiments revealed interesting difference in the binding mode: The cis-1 isomer binds anions in a mixed binding mode featuring a combination of hydrogen bonding and anion-pi interactions resulting in an unexpected strong binding. On the other hand, the trans-1 isomer displays only hydrogen bonding …

Go to article

Classification And Cluster Analysis Of Complex Time-Of-Flight Secondary Ion Mass Spectrometry For Biological Samples, Stephen E. Reichenbach, Xue Tian, Qingping Tao, Alex Henderson Jan 2009

Classification And Cluster Analysis Of Complex Time-Of-Flight Secondary Ion Mass Spectrometry For Biological Samples, Stephen E. Reichenbach, Xue Tian, Qingping Tao, Alex Henderson

School of Computing: Conference and Workshop Papers

Identifying and separating subtly different biological samples is one of the most critical tasks in biological analysis. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is becoming a popular and important technique in the analysis of biological samples, because it can detect molecular information and characterize chemical composition. ToF-SIMS spectra of biological samples are enormously complex with large mass ranges and many peaks. As a result the classification and cluster analysis are challenging. This study presents a new classification algorithm, the most similar neighbor with a probability-based spectrum similarity measure (MSN- PSSM), which uses all the information in the entire ToF- SIMS …

Go to article

Quantitative Measurement Of Surface Trapping In Europium Iii Doped Ytrium Oxide (Y20₃: Eu 3+), Rusty Mann Jan 2009

Quantitative Measurement Of Surface Trapping In Europium Iii Doped Ytrium Oxide (Y20₃: Eu 3+), Rusty Mann

Undergraduate Honors Theses

This study is the beginning of a project that is aimed at quantitatively modeling energy losses due to crystalline surface defects of nanometer sized particles of Yttrium oxide doped with europium (Y2O3:Eu3+). Information gained from this study will be useful to lighting and displaying industries as well as to the nano-tech community as we are investigating the behavior of matter at the interface between bulk and molecular properties. Five different particles diameters, ranging from 112 nm to 37 nm, of Y2O3:Eu3+ were synthesized at both 5% and 10% concentrations …

Go to article

Estimating The Contribution Of Point Sources To Atmospheric Metals Using Single-Particle Mass Spectrometry, David C. Snyder, James J. Schauer, Deborah S. Gross, Jay R. Turner Jan 2009

Estimating The Contribution Of Point Sources To Atmospheric Metals Using Single-Particle Mass Spectrometry, David C. Snyder, James J. Schauer, Deborah S. Gross, Jay R. Turner

Chemistry Faculty Work

Single-particle mass spectra were collected using an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) during December of 2003 and February of 2004 at an industrially impacted location in East St. Louis, IL. Hourly integrated peak areas for twenty ions were evaluated for their suitability in representing metals/metalloids, particularly those reported in the US EPA Toxic Release Inventory (TRI). Of the initial twenty ions examined, six (Al, As, Cu, Hg, Ti, and V) were found to be unsuitable due to strong isobaric interferences with commonly observed organic fragments, and one (Be) was found to have no significant signal. The usability of three ions …

Go to article

Organocatalysis With Endogenous Compounds: Towards Novel Non-Enzymatic Reactions, David G. Alberg, Thomas B. Poulsen, Søren Bertelsen, Kasper L. Christensen, Rune D. Birkler, Mogens Johannsen, Karl Anker Jørgensen Jan 2009

Organocatalysis With Endogenous Compounds: Towards Novel Non-Enzymatic Reactions, David G. Alberg, Thomas B. Poulsen, Søren Bertelsen, Kasper L. Christensen, Rune D. Birkler, Mogens Johannsen, Karl Anker Jørgensen

Chemistry Faculty Work

The aldol reaction of the endogeneous compounds acetone and methylglyoxal has been studied using organocatalysis in relation to biologically relevant non-enzymatic reactions. Under preparative conditions, 3-hydroxy-2,5-hexadione, known as Henze’s ketol, is formed in high yield and with enantioselectivities up to 88% ee. Furthermore, Henze’s ketol is also formed under simulated physiological conditions at micromolar scale, indicating that this reaction might take place in living organisms.

Go to article

Subarctic Atmospheric Aerosol Composition: 2. Hygroscopic Growth Properties, Hanna Herich, Lukas Kammermann, Beth Friedman, Deborah S. Gross, Ernest Weingartner, Ulrike Lohmann, Peter Spichtinger, Martin Gysel, Urs Baltensperger, Daniel J. Cziczo Jan 2009

Subarctic Atmospheric Aerosol Composition: 2. Hygroscopic Growth Properties, Hanna Herich, Lukas Kammermann, Beth Friedman, Deborah S. Gross, Ernest Weingartner, Ulrike Lohmann, Peter Spichtinger, Martin Gysel, Urs Baltensperger, Daniel J. Cziczo

Chemistry Faculty Work

Subarctic aerosols were sampled during July 2007 at the Abisko Scientific Research Station Stordalen site in northern Sweden with an instrument setup consisting of a custombuilt Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) connected in series to a single particle mass spectrometer. Aerosol chemical composition in the form of bipolar single particle mass spectra was determined as a function of hygroscopic growth both in situ and in real time. The HTDMA was deployed at a relative humidity of 82%, and particles with a dry mobility diameter of 260 nm were selected. Aerosols from two distinct air masses were analyzed during the …

Go to article

Polyelectrolyte-Linked, Multi-Layer Film Assemblies Of Aqueous Nanoparticles And Nanoshells, Anne Galyean Jan 2009

Polyelectrolyte-Linked, Multi-Layer Film Assemblies Of Aqueous Nanoparticles And Nanoshells, Anne Galyean

Honors Theses

Multi-layer films of nanoparticles and nanoshells featuring various polymeric linkage molecules have been assembled and their optical properties characterized. The growth dynamics, including molecular weight effects, and stability of the various nanoparticle film constructions, using both single polymer as well as combinations of alternating charge polyelectrolytes as linking mechanisms, are presented. The polymeric linkers studied include poly-L-lysine, poly-L-arginine, poly(allylamine hydrochloride), and polyamidoamine dendrimers. Significantly air stable films were achieved with the use of multi-layered polymeric bridges between the nanoparticles and nanoshells. Optical sensitivity normally observed with these nanomaterials in solution was observed for their corresponding film geometries, with the nanoshell …

Go to article

Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m Jan 2009

Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m

Turkish Journal of Chemistry

Several ring expansion products carrying vinylic bromo functionality were synthesized by opening of the geminal dibromobicyclo[n.1.0]alkanes ring. Dibromocarbene was formed from bromoform and potassium tert-butoxide in hexane. Its reaction with various cyclic alkenes was the resultant dibromobicyclo[n.1.0]alkanes. Then, opening was performed using AgNO_3 in various solvent systems, such as acetic acid/DMSO, acetic acid/DMF, CH_3OH/acetone, and H_2O/DMF.

Go to article

Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu Jan 2009

Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu

Turkish Journal of Chemistry

The water-gas shift (WGS) activity of bimetallic Pt-Ni/Al_2O_3 catalysts was investigated in the temperature range 200-450 °C using an idealized feed composition consisting of 3% CO and 6%-10% H_2O. The effects of the Ni content, space velocity, and H_2O/CO ratio on the catalytic performance of the catalysts were studied. An increase in the Ni content and H_2O/CO ratio shifted the carbon monoxide conversion--temperature curve toward lower reaction temperatures. No detectable methane formation was observed in the catalytic reaction tests. The results indicate that Pt-Ni/Al_2O_3 catalysts are highly selective and active for water-gas shift reactions under idealized conditions.

Go to article

Synthesis, Characterization, And Antibacterial Effect Of 4-Methoxy-2-(5-H/Me/Cl/No_2-1h-Benzimidazol-2-Yl)- Phenols And Some Transition Metal Complexes, Aydin Tavman, Serkan İki̇z, Arzu Funda Bağcigi̇l, N. Yakut Özgür, Seyyal Ak Jan 2009

Synthesis, Characterization, And Antibacterial Effect Of 4-Methoxy-2-(5-H/Me/Cl/No_2-1h-Benzimidazol-2-Yl)- Phenols And Some Transition Metal Complexes, Aydin Tavman, Serkan İki̇z, Arzu Funda Bağcigi̇l, N. Yakut Özgür, Seyyal Ak

Turkish Journal of Chemistry

4-Methoxy-2-(5-H/methyl/chloro/nitro-1H-benzimidazol-2-yl)-phenol(HL_X; X=1-4) ligands and HL_1 complexes with Fe(NO_3)_3, Cu(NO_3)_2, AgNO_3, and Zn(NO_3)_2 were synthesized and characterized. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-IR, UV-visible, and ^1H- and ^{13}C-NMR. Antibacterial activity of the free ligands, their hydrochloride salts, and the complexes was evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimum inhibitory concentration (MIC) dilution method, against 9 bacteria, and the results were compared with penicillin-G and oxytetracycline. It was observed that HL_1, [Ag(HL_1)](NO_3), and [Cu(L_1)_2](H_2O)_2 are effective on S. epidermidis, S. aureus, and …

Go to article

Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu Jan 2009

Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu

Turkish Journal of Chemistry

Due to its good burning characteristics and high cetane number, dimethylether (DME) is considered as a highly attractive and clean alternative to diesel fuel. This ether can be produced by methanol dehydration reaction over solid acid catalysts. In the present study, activities of mesoporous aluminosilicate catalysts prepared by the hydrothermal synthesis route and containing Al/Si atomic ratios ranging between 0.03 and 0.18 were tested in methanol dehydration. The optimum Al/Si ratio was 0.09 for DME synthesis. Activity of silicotungstic acid (STA) impregnated aluminosilicate was also tested. This STA impregnated catalyst showed very high DME yield values at temperatures as low …

Go to article

Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao Jan 2009

Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao

Turkish Journal of Chemistry

Six novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles were synthesized by introducing 1,3,4-oxadiazole moiety into the stilbene skeleton. The synthesis route included the cyclization of p-toluic acid and hydrazine hydrate catalyzed by polyphosphoric acid (PPA), bromination of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), esterification, and the Wittig-Horner reaction. All the title compounds were characterized by ^1H-NMR, MS, and elemental analysis. UV-Vis absorption and fluorescence emission spectra in THF solution were investigated; the compounds may have potential for use in organic optical materials.

Go to article

Improved Photostability Of Pvc Films In The Presence Of 2-Thioacetic Acid-5-Phenyl-1,3,4-Oxadiazole Complexes, Emad A. Yousif, Salah A. Aliwi, Ameer A. Ameer, Jaleel R. Ukal Jan 2009

Improved Photostability Of Pvc Films In The Presence Of 2-Thioacetic Acid-5-Phenyl-1,3,4-Oxadiazole Complexes, Emad A. Yousif, Salah A. Aliwi, Ameer A. Ameer, Jaleel R. Ukal

Turkish Journal of Chemistry

The photostabilization of poly(vinyl chloride) (PVC) films by 2-thioacetic acid-5-phenyl-1,3,4-oxadiazole with Sn(II), Ba(II), Ni(II), Zn(II), Cu(II), and Ca(II) complexes was investigated. PVC films containing different concentrations of complexes ranging from 0.1% to 0.5% by weight were produced by the same casting method from THF solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl and polyene indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (\Phi _{cs}) of these complexes in PVC films was evaluated …

Go to article

Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman Jan 2009

Air-Sea Gas Exchange Of Co2 And Dms In The North Atlantic By Eddy Covariance, Scott Miller, Christa Marandino, Warren J. De Bruyn, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report the first simultaneous eddy covariance flux measurements of CO2 and dimethylsulfide (DMS) over the open ocean for two North Atlantic cruises. After normalization for Schmidt number, the two gases give essentially identical gas transfer coefficients and wind speed dependences for the wind speed range 2-10 ms(-1). The data indicate a linear relationship between the gas transfer coefficient and mean wind speed, with measured gas transfer coefficients slightly above the Wanninkhof (1992) parameterization, particularly at low wind speeds. Citation: Miller, S., C. Marandino, W. de Bruyn, and E. S. Saltzman (2009), Air-sea gas exchange of CO2 and DMS in …

Go to article

Co Chemisorption On The Surfaces Of The Golden Cages, Wei Huang, Satya S. Bulusu, Rhitankar Pal, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2009

Co Chemisorption On The Surfaces Of The Golden Cages, Wei Huang, Satya S. Bulusu, Rhitankar Pal, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

We report a joint experimental and theoretical study of CO chemisorption on the golden cages. We find that the Au17 − cage is highly robust and retains its cage structure in Au17 − (CO)−. On the other hand, the Au16 − cage is transformed to a structure similar to Au17 − upon the adsorption of CO. Au18 − is known to consist of two nearly degenerate structures, i.e., a cage and a pyramidal isomer, which coexist in the cluster beam. However, upon CO chemisorption only the cage isomer is observed while the pyramidal …

Go to article

First Prev Next Last