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Full-Text Articles in Physical Sciences and Mathematics
Separation And Characterization Of Components Of Catalytic Cracker Feed Using Centrifugal Partition Chromatography, Randy A. Menges, Daniel W. Armstrong, Larry A. Spino
Separation And Characterization Of Components Of Catalytic Cracker Feed Using Centrifugal Partition Chromatography, Randy A. Menges, Daniel W. Armstrong, Larry A. Spino
Chemistry Faculty Research & Creative Works
Centrifugal partition chromatography (CPC) was used to fractionate a catalytic-cracking feedstock (i.e., catalytic cracker feed) into 16 separate fractions in the descending mode and 5 fractions in the inverse or ascending mode. Each fraction was analyzed by UV, fluorescence, and synchronous luminescence (SL) spectroscopy as well as by gas chromatography/mass spectrometry (GC/MS). It appeared that CPC can be used to fractionate larger samples of this type and with a greater degree of selectivity than previously reported preparative HPLC approaches. The SL spectra tended to be much more useful and information rich for these complex mixtures as compared to UV or …
Symmetrically H-Bridged Dimer Of 2-Carboxylatobenzenediazonium. The 1:1 Complex Between 2-Carboxybenzenediazonium Chloride And Benzenediazonium-2-Carboxylate, Christopher J. Horan, Paul E. Haney, Charles Leslie Barnes, Rainer Glaser
Symmetrically H-Bridged Dimer Of 2-Carboxylatobenzenediazonium. The 1:1 Complex Between 2-Carboxybenzenediazonium Chloride And Benzenediazonium-2-Carboxylate, Christopher J. Horan, Paul E. Haney, Charles Leslie Barnes, Rainer Glaser
Chemistry Faculty Research & Creative Works
The two zwitterions in the H-bridged dimer of 2-carboxylatobenzenediazonim (1) are linked by a crystallographically symmetric O⋯Hctdot;O hydrogen bond with an O⋯O distance of 2.436 (3) Å. Comparison of the (1) with the other benzenediazonium salts shows that the phenyl ring distortions in (1) are determined primarily by the diazonium substituent with only modest additional effects by the carboxylato group. Intramolecular neighboring goup interactions between the N2 group and the orthoCOO(H) group are indicated and are discussed. The terminal N atom of the diazonium group is bent away from the neighboring carboxylato group. The N2 and the …
A Neutron Diffraction And Mössbauer Effect Study Of The Magnetic Properties Of Pr₂Fe₁₇ And Pr₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, William B. Yelon, K. H. Buschow
A Neutron Diffraction And Mössbauer Effect Study Of The Magnetic Properties Of Pr₂Fe₁₇ And Pr₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, William B. Yelon, K. H. Buschow
Chemistry Faculty Research & Creative Works
The neutron diffraction powder patterns of Pr2Fe17 and Pr2Fe17N2.6 have been measured at 295 K and refined within the Th2Zn17 structure type to give the structural changes which occur upon nitrogenation; changes which include a 6.4% expansion of the unit cell volume. The Mössbauer spectra of Pr 2Fe17 and Pr2Fe17N2.6 have been measured between 85 and 295 K and analyzed with a model which is based on the Wigner-Seitz cell environment of each iron site, the basal orientation of the magnetization, and …
Derivatized Cyclodextrins Immobilized On Fused-Silica Capillaries For Enantiomeric Separations Via Capillary Electrophoresis, Gas Chromatography, Or Supercritical Fluid Chromatography, Daniel W. Armstrong, Yubing Tang, Timothy Ward, Molly Nichols
Derivatized Cyclodextrins Immobilized On Fused-Silica Capillaries For Enantiomeric Separations Via Capillary Electrophoresis, Gas Chromatography, Or Supercritical Fluid Chromatography, Daniel W. Armstrong, Yubing Tang, Timothy Ward, Molly Nichols
Chemistry Faculty Research & Creative Works
No abstract provided.
2-Carboxybenzenediazonium Chloride Monohydrate, Christopher J. Horan, Charles Leslie Barnes, Rainer Glaser
2-Carboxybenzenediazonium Chloride Monohydrate, Christopher J. Horan, Charles Leslie Barnes, Rainer Glaser
Chemistry Faculty Research & Creative Works
C7H5N2O2 +.Cl-H2O, Mr = 202.60, monoclinic, C2c, a = 25.62(3), b = 4.964(2), c = 14.900 (14)Å, β = 107.15 (4)°, V = 1811 (3)Å3, Z = 8, Dx = 1.486 g cm-3, λ(Mo Kα) = 0.71073 Å, µ = 3.9 cm-1, F(000) = 832, T = 298 K, R = 0.035 for 1275 observed reflections. The terminal N atom of the diazonium group is bent away from the carboxyl group. The N2 and the …
Infarct Topography And Hemiparesis Profiles With Cerebral Convexity Infarction: The Stroke Data Bank, J. P. Mohr, M. A. Foulkes, A. T. Polis, D. (Daniel) B. Hier, C. S. Kase, T. R. Price, T. K. Tatemichi, P. A. Wolf
Infarct Topography And Hemiparesis Profiles With Cerebral Convexity Infarction: The Stroke Data Bank, J. P. Mohr, M. A. Foulkes, A. T. Polis, D. (Daniel) B. Hier, C. S. Kase, T. R. Price, T. K. Tatemichi, P. A. Wolf
Chemistry Faculty Research & Creative Works
For the 183 of 1276 Patients in the NINDS Stroke Data Bank with Convexity Infarction in the Middle Cerebral Artery Territory, the Size of the Infarct Did Not Differ between the Two Sides But the Location of the Main Site of the Infarct Differed: on the Left Side, It Was Centered in the Inferior Parietal Region, and Was Mid-Frontal on the Right. There Was a Good Correlation between Infarct Size and Weakness Severity Whether Estimated by overall Motor Function on One Side, Arm, or Hand Alone. There Was a Poor Correlation, However, for Lesion Location (Lower Third, Middle Third or …
Aminolysis Of Activated Esters Of Indole-3-Acetic Acid In Acetonitrile, Michael J. Pfeiffer, Samir B. Hanna
Aminolysis Of Activated Esters Of Indole-3-Acetic Acid In Acetonitrile, Michael J. Pfeiffer, Samir B. Hanna
Chemistry Faculty Research & Creative Works
Seven activated esters of indole-3-acetic acid (IAA) [4-oxo-l,2,3-benzotriazin-3-yl indole-3-acetate (IAA-3HBO), succinimido indole-3-acetate (IAA-NHS), 5-norbornene-1,3-dicarboximido indole-3-acetate (IAA-NHND), phthalimido indole-3-acetate (IAA-NHP), naphthalimido indole-3-acetate (IAA-NHN), 4-nitrophenyl indole-3-acetate (IAA-4NP), 8-quinolyl indole-3-acetate (IAA-8HQ)] were prepared and characterized. Their kinetics of aminolysis with butylamine, piperidine, and pyrrolidine in acetonitrile were investigated. In general, the observed pseudo-first-order rate constants, kobs, fit the two-term rate equation kobs = k1[amine] + k2[amine]2. For the aminolysis of six of the esters with piperidine there was no measurable k2 term. The 8-hydroxyquinoline ester and N-hydroxy-naphthalimide ester of indole-3-acetic acid had no measurable k2 term for aminolysis with either pyrrolidine or piperidine. …
Tetrabutylammonium Benzoate‐Initiated Polymerization Of Propylene Oxide, Xuemin Chen, Michael R. Van De Mark
Tetrabutylammonium Benzoate‐Initiated Polymerization Of Propylene Oxide, Xuemin Chen, Michael R. Van De Mark
Chemistry Faculty Research & Creative Works
The polymerization of propylene oxide by the benzoate anion was aided through the use of the tetrabutylammonium counterion. The effect of the tetrabutylammonium ion was to increase the solubility of the salt and to increase the ion separation. The polymerization was carried out in a pressure reactor at temperatures from 40 to 108°C, producing polymer yields of 2–78%. The study addressed the general effects of solvent, temperature, and ratio of initiator to monomer. © 1993 John Wiley & Sons, Inc. Copyright © 1993 John Wiley & Sons, Inc.
Enantiomeric Separation Of Chiral Components Reported To Be In Coffee, Tea, Or Cocoa, Apryll M. Stalcup, K. Helen Ekborg, Mary P. Gasper, Daniel W. Armstrong
Enantiomeric Separation Of Chiral Components Reported To Be In Coffee, Tea, Or Cocoa, Apryll M. Stalcup, K. Helen Ekborg, Mary P. Gasper, Daniel W. Armstrong
Chemistry Faculty Research & Creative Works
Literally hundreds of volatile compounds have been identified in coffee, tea, and cocoa. A significant proportion of these compounds are known to be chiral. The enantiomeric composition of most of these compounds is unknown, and until recently there were no efficient analytical procedures for their identification. The advent of cyclodextrin-based chiral stationary phases for capillary gas chromatography provides effective means for the enantioselectivity analysis of many of these compounds. Some of these are known to be flavor and fragrance components that occur naturally or are produced from the manufacturing process (e.g., fermentation, drying, and roasting). © 1993, American Chemical Society. …