Chemistry Commons^™

Separation And In Situ Catalytic Testing Of A Dirhodium Tetraphosphine Catalyst, Bobby Lloyd Barker

LSU Doctoral Dissertations

Attempts to study the asymmetric hydroformylation abilities of [rac-Rh₂(nbd)₂(et,ph-P4)](BF₄)₂ were made through the separation of the enantiomers of et,ph-P4 using a chiral HPLC column. Efforts were also made to optimize the NiCl₂ separation chemistry for the methyl analogue of et,ph-P4 for use in asymmetric hydroformylation. A study of hydroformylation of olefins using [rac-Rh₂(nbd)₂(et,ph-P4)](BF₄)₂ in ionic liquids was also performed, leading directly to the important (and unexpected) effect of increased hydrogen pressure on [rac-Rh₂(nbd)₂(et,ph-P4)](BF₄)₂ in the acetone/water system to …

Synthesis And Characterization Of Dendrimer Templated Supported Bimetallic Pt-Au Nanoparticles, Huifang Lang, S. Maldonado, K. J. Stevenson, Bert D. Chandler

Chemistry Faculty Research

Bimetallic dendrimer-stabilized nanoparticles (DSNs) were used to prepare supported Pt-Au catalysts within the bulk miscibility gap for this binary system. Hydroxy-terminated generation 5 PAMAM dendrimers were used to prepare Cu0 nanoparticles (NPs). The Cu⁰ NPs were subsequently used to reduce K₂PtCl₄ and HAuCl₄, preparing stabilized bimetallic Pt-Au NPs with a 1:1 stoichiometry. The stabilized NPs were adsorbed onto a high surface area silica support and thermally activated to remove the dendrimers. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and infrared spectroscopy of adsorbed CO showed that this preparation route resulted in NPs in …

Electronic Structural Investigations Of Bi- And Polymetallic Complexes Using Quantum Mechanical Methods, Zakiya Sheni Wilson

LSU Doctoral Dissertations

Understanding the dynamics influencing chemical reactivity is essential for properly exploiting matter into more useful purposes. In that manner, computational chemistry is a tool frequently used to study chemical properties at the most intimate level, i.e. the single molecule.

With this work, we probe the chemistry governing a variety of multi-faceted bi- and polymetallic compounds. To date our research consists of four major projects: bimetallic rhodium-catalyzed hydroformylation and aldehyde-water shift hydrocarboxylation catalysis; a novel linear M-H-M interaction in a bridged bis(dialkylphosphino)methane complex of nickel; and CeBe₁₃, a heavy fermion conductor. Computational investigations on these systems allow us to …

Distributions Of Nobel Metal Pd And Pt In Mesoporous Silica, J. Arbiol, A. Cabot, J. R. Morante, Fanglin Chen, Meilin Liu

Faculty Publications

Mesoporous silicananostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3–5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclusters to nanowires). It is observed that these materials have high catalyticproperties for CO–CH₄CO–CH₄CO–CH₄ combustion, even in a thick film form. In particular, results indicate that the Pt and Pd dispersed in mesoporous silica are catalytically active as a selective filter for gas sensors.

Studies On The Roles Of Atp In Nitrogenase Catalysis, Wei Wu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogenase is the enzyme that catalyzes the reduction of nitrogen to ammonia in a reaction requiring MgATP hydrolysis. Two component proteins of nitrogenase are the iron protein (Fe protein) and the molybdenum-iron protein (MoFe protein).

Nitrogenase contains two nucleotide binding sites. During catalysis, the Fe protein binds two MgATP first. The conformational changes induced upon MgATP binding allow the Fe protein to associate with the MoFe protein. After the formation of the Fe protein-MoFe protein complex, a single electron is transferred from the Fe protein to the MoFe protein, an event that is coupled to MgATP hydrolysis in the Fe …

Probing The Mechanisms Of Enantioselective Hydrogenation Of Simple Olefins With Chiral Rhodium Catalysts In The Presence Of Anions, Jillian M. Buriak, Jason C. Klein, Deborah Herrington, John A. Osborn

Peer Reviewed Articles

The strong influence of various anions upon the hydrogenation of 2-phenyl-1-butene, catalyzed by chiral rhodium catalysts was investigated. Both sulfonates and halides exert large increases in the enantioselectivity when [Rh{(−)-bdpp}(NBD)]ClO4 (bdpp=2,4-bis(diphenylphosphino)pentane, NBD=2,5-norbornadiene) is used as the catalyst precursor at high pressures (70 atm) of dihydrogen in nonpolar solvents. A dihydride mechanism similar to that for Wilkinson's catalyst [RhCl(PPh3)3] was shown to be operating at both high- and low-pressure conditions through a combination of catalytic studies, 31P, 1H and parahydrogen-induced polarization (PHIP) NMR experiments. With sulfonate and in neat methanol, however, a mechanistic switch takes place from a dihydride route (dihydrogen …

Catalytic Oxidation Of Chlorinated Hydrocarbons Over Powdered Transition Metal Oxide, Sanmei Xu

Theses

This study addresses the ability of powdered transition metal oxides such as manganese oxide, iron oxide and copper oxide to catalytically oxidize low concentrations of chlorinated hydrocarbons with air. The catalytic oxidation of trichloroethylene and dichloromethane in a tubular reactor system was evaluated experimentally as a function of temperature and space velocity. Gas chromatography with electron capture detector and flame ionization detector was used for quantitative analysis of feed and product streams. Gas chromatography/mass spectrometry and gas chromatography/Fourier transform infrared spectroscopy were used to identify all oxidation products. The results indicate that over 99% conversion of trichloroethylene is achieved at …

A Two Part Research Report: Aromatic Nucelophilic Fluoroal Koxylation Via Cationic Phase Transfer Catalysis And Reactions Of Unsymmetrical Vinamidinium Salts With Organometallic Reagents, Joseph E. Coury

Retrospective Theses and Dissertations

This report discusses research which was conducted in two areas: the study of aromatic nucleophilic fluoroalkoxylation assisted via cationic phase transfer catalysis and the study of unsymmetrical vinamidinium salts and their reactions with organometallic reagents.

Sodium alkoxides have been successfully used to fluoroalkoxylate activated halo- aryl and heteroaryl substrates under phase transfer catalysis conditions. Optimum reaction conditions incorporated tetra-n-butyl-phosphonium bromide as the catalyst and refluxing toluene as the solvent medium. Different quarternary phosphonium and arrmonium salts have been evaluated as catalysts: also, the effects of activating groups, leaving groups, and nucleophiles have been reported.

The reaction of 3-dimethylamino-3-phenyl-prop-2-en-l-ylidendimethyliminium perchlorate with …

Separation Of Piperylene Concentrate Via Metathesis Catalysis, Donald R. Allred

Retrospective Theses and Dissertations

Diolefin metathesis, using a Re2O7 catalyst, failed to show a reactivity difference due to conjugation of double bonds. However, the same system allows reaction of pentadiene while not affecting cyclopentene yielding a successful reaction ΓÇô separation scheme for a piperylene concentrate mixture.

Synthesis And Evaluation Of Polymer Supported Homogenous Oxidation Catalysts, Raymond J. Riley

Retrospective Theses and Dissertations

Polystyrene bis(salicylaldehyde)-propylene-1,3-diiminato Cobalt (II) [salen] and Polystyrene bis(2,4-pentanedione)-propylene-1,3-diiminato Cobalt (II) [BAE] were prepared stepwise from chloromethylated polystyrene. In addition, a new preparation of a Schiff base was attempted resulting in Polystyrene bis(salicylaldehyde)-isobutylene-1,3-diiminoato Cobalt (II) being produced. Optimum reaction conditions were determined with regard tot ime, temperature, reaction ratios and solvent for each step for the reaction. The ability of the above named Cobalt (II) Schiff bases to oxidize 3-methyl indole to give the corresponding o-formylaminoacetophenone was also studied. One polymer-bound Schiff base cobalt catalyst (co-salen) demonstrated a very small amount of catalytic activity resulting in a minimum amount of o-formylaminoacetophenone …

Acid-Base Catalysis Of The Enolization Of Acetone, Janet Louise Larson

Undergraduate Honors Theses

Measurements are reported on the rate of iodination of acetone at 25°c in arsenate, phosphate, and diethylmalonic acid buffers at a constant ionic strength of 0.2. Unlike earlier results which indicate that in acetic acid buffer the expression for the reaction velocity contains an appreciable kinetic term involving the product of the concentrations of acid and anion, it has been found from the present work that such a term is experimentally immeasurable for the above mentioned buffers. This finding coupled with the relatively powerful catalysis by the phosphate and arsenate dianions could imply the simultaneous participation of these species in …

Rhenium Trioxide, Rhenium Heptoxide And Rehnium Trichloride As Hydrogenation Catalysts, William J. Bartley

Theses and Dissertations

The purpose of this study was to characterize the catalytic activity of rhenium trioxide and rhenium trichloride as hydrogenation catalysts. Work was also undertaken to further study the catalytic properties of rhenium heptoxide. The activity of this latter compound had received some study in a previous project. A complete review of the literature has been made on the organic and inorganic chemistry of rhenium trioxide and rhenium trichloride. A survey of the literature on catalytic hydrogenation and the chemistry of rhenium heptoxide has also been included. Rhenium trioxide was prepared by three similar methods. The first two involved the formation …

Rhenium Catalysis I. Hydrogenation And Hydroformylation Using Rhenium Carbonyl Compounds ; Ii. Hydrogenation Using Catalysts Obtained From The Reduction Of Perrhenates With Metals In Aqueous Solution, Terry G. Selin

Theses and Dissertations

The purpose of this work was to investigate the catalytic activity in both hydrogenation and hydroformylation reactions of rhenium preparations which have not been previously characterized. Rhenium pentacarbonyl was prepared in good yield from rhenium heptoxide and carbon monoxide. The optimum conditions for preparation were 25 hours per gram of dry rhenium heptoxide at 250° under 3000 psig. (initial) of carbon monoxide. Rhenium chloropentacarbonyl was prepared in 62% yield from potassium chlororhenite and carbon monoxide at high temperatures and pressures. The iodopentacarbonyl was prepared in 29% yield from potassium perrhenate, methyl iodide, and carbon monoxide. The preparation of rhenium hydrocarbonyl …

Iron And Cobalt Salts As Catalysts In The Oxidation Of Sodium Sulfite By Free Oxygen, Loren C. Bryner

Theses and Dissertations

The present investigation was carried out to show the catalytic effect of some iron and cobalt salts on the oxidation of sodium sulfite solutions by free oxygen. The rate of reaction was determined by measuring the volume of water required to replace the absorbed oxygen. A photograph and diagrammatical arrangement of the apparatus is given, (Page 14). From the preliminary experiments it was found that the rate of oxidation of sodium sulfite solutions is dependent upon concentration, and speed of the shaker.