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Articles 631 - 660 of 740
Full-Text Articles in Chemistry
Rhenium Catalyzed Hydrogenation Of Maleic Anhydride And Crotonaldehyde, William Russel Dixon
Rhenium Catalyzed Hydrogenation Of Maleic Anhydride And Crotonaldehyde, William Russel Dixon
Theses and Dissertations
The preparation of a number of supported rhenium catalysts is reported. The determination of their activity and selectivity and of optimal reaction parameters for the reduction of maleic anhydride and crotonaldehyde is reported. Optimal time of hydrogenation was chosen as one hour and pressures were chosen as 2000 psig for crotonaldehyde and 3000 psig for maleic anhydride. Quantitative reduction of maleic anhydride to tetrahydrofuran occurred at 275° with charcoal supported rhenium catalysts. Lower temperatures (ca. 200°) produce quantitative amounts of butyrolactone. Unsupported catalysts at low temperatures (100°) selectively reduce crotonaldehyde to crotyl alcohol, but at very low conversion rates. Temperatures …
Toward Hydrogen Bonds Of Predictable Geometry, Robert Shao-Chih Hsu
Toward Hydrogen Bonds Of Predictable Geometry, Robert Shao-Chih Hsu
Theses and Dissertations
A literature review on the geometry of hydrogen bonding showed that the geometry is often de-emphasized or even ignored, probably because of the inherent flexibility of many systems studied. Examination of molecular models suggested the geometrically constrained bicyclo [2, 2, 1] heptane system wherein hydrogen bond distances and angles might be more easily predicted. Dihydroboration-oxidation of norbornadiene was shown to yield exo, exo-2,5-norbornadiol, thus clarifying uncertainties in the literature. 2, 5-Norbornadiol was oxidized to the corresponding dione, heretofore inadequately characterized. Several derivatives of the dione were prepared, and spectral data were accumulated for the dione, its precursor, and its derivatives. …
Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Mark J. Rowe
Enzymatic Synthesis Of Oligoribonucleotides Of Defined Base Sequence, Mark J. Rowe
Theses and Dissertations
The synthetic reaction of ribonuclease T_1 has been studied as to its potential for the synthesis of oligoribonucleotides of defined base sequence. Conditions have been determined for maximum synthesis with respect to percentage incorporation of both guanosine 2',3'-cyclic phosphate (donor), and cytidine (acceptor). With regard to maximum acceptor incorporation, a donor blocked at the 5'-hydroxyl has been used to drive the reaction. It has also been shown that acceptor incorporation decreases as the chain-length increases up to the hexanucleotide. Synthesis of a 3'-blocked substrate for polynucleotide phosphorylase for use in chain termination studies was attempted using adenylate kinase. In this …
Synthesis And Metal Coordination Properties Of Some Cyclic Polyethers And Polythioethers, Barry Lant Haymore
Synthesis And Metal Coordination Properties Of Some Cyclic Polyethers And Polythioethers, Barry Lant Haymore
Theses and Dissertations
Thermodynamic values for cation-cyclic polyether interactions for several systems are reported and discussed in light of ligand geometry, cation selectivity, solvent effects, structure, stoichiometry and the nature of the coordinate bond. Cyclic polyethers are shown to be remarkably good ligands even in water and to have marked selectivity for d0, d10 and d10 s2 cations. Syntheses of one new cyclic polyether and several new mixed cyclic polyether-thioethers are reported. Cyclic chelates with smaller rings are shown to prefer smaller cations, but this selectivity is masked by the hydration energy of the cation. Except for thiophillic cations such as Hg2+ and …
On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith
On The Mechanism Of Low-Temperature Termolecular Atomic Recombination, Russell T. Pack, Richard L. Snow, Wesley D. Smith
Faculty Publications
A simple theory of gas-phase termolecular atomic recombination kinetics is presented which treats the bound-complex (BC) mechanism in a fashion which parallels the Roberts, Bernstein, and Curtiss resonance theory of the energy-transfer (ET) mechanism. The ET rate constant has a low temperature maximum, but the BC rate constant does not. The contributions of the two mechanisms to the low-temperature recombination of hydrogen atoms, with He, Ar, and H2 as third bodies, are estimated and compared. The presence (absence) of a low-temperature maximum in the observable total rate constant is determined by absence (presence) of bound vibrational levels of the hydrogen-third …
The Thermal Decomposition Of 2,2'-Azoisobutane, Mervin Dewain Atwood
The Thermal Decomposition Of 2,2'-Azoisobutane, Mervin Dewain Atwood
Theses and Dissertations
Nitrogen, isobutane, isobutylene and 2,2,3,3-tetramethylbutane are the only products found in the thermal decomposition of 2,2'-azoisobutane. They are the results of the direct free radical dimerization and disproportionation. Ratio of the rate constants of disproportionation to dimerization was found to be 1.9 at 268°C and 4.5% azobutane in helium. This compared with Blackham and Eatough's value of 1.4 at 243°C and 3.6 at 290°C with 4% azobutane in helium. The ratio of the disproportionation to dimerization increased with an increase in temperature. A change in contact time affected the ratio at lower reaction temperatures but had little effect on it …
An Investigation Of Some Free Radicals.|Ni.|Pdecomposition Of Nitrosyl Disulfonate Ion In Polar Non-Aqueous Solvents.|Nii.|Preaction Between 2,2-Diphenyl -1- Picryl Hydrazyl And Nitrosyl Disulfonate Ion Free Radicals, Janan Mary Hayes
Theses and Dissertations
Part I reports the stud y of the decomposition of nitrosyl disulfonate ion in DMSO, acetonitrile, and dichloromethane. A multi-step mechanism involving sulfite ion, sulfite ion radical, and nitrosyl monosulfonate radical as intermediates is proposed. The products of the decomposition are nitrosonium ion, hydroxylamine disulfonate ion, and hydroxylamine trisulfonate ion. A competitive chain reaction was observed when the decomposition occurred in DMSO. The chain reaction was insignificant in carefully dried acetonitrile and dichloromethane. Part II reports the study of the reaction between 2,2-diphenyl-1-picryl hydrazyl (DPPH) and nitrosyl disulfonate ion. Product analysis and kinetic data obtained from stopped-flow procedures suggest that …
Studies Of Pig Brain Thiamin Pyrophosphokinase, James Weldon Peterson
Studies Of Pig Brain Thiamin Pyrophosphokinase, James Weldon Peterson
Theses and Dissertations
Pig brain thiamin pyrophosphokinase (TPK) (ATP: thiamin pyrophosphotransferase, EC 2.7.6.2) was purified 260-fold over extracts of brain acetone powder. The purification was followed using a direct, radiometric assay. As determined in an analytical ultracentrifuge and by disc-gel electrophoresis, the most highly purified enzyme preparations were not homogeneous. The purified enzyme has a broad pH optimum extending from 8.3 to 9.3 in phosphate-glycylglycine buffer. It has an isoelectric point at about pH 4.2. For optimal enzymatic activity, the ratio of magnesium to ATP must be 0.6. Any deviation from this ratio causes a rapid drop in enzymatic activity. A study of …
Solid-Liquid Phase Equilibria Studies :|Bi. Several Charge Transfer Systems ; Ii. A Metallic System ; Iii. A Liquid Crystal, Dee Edward Oyler
Solid-Liquid Phase Equilibria Studies :|Bi. Several Charge Transfer Systems ; Ii. A Metallic System ; Iii. A Liquid Crystal, Dee Edward Oyler
Theses and Dissertations
Solid-liquid phase equilibria studies were used to investigate possible compound formation in solutions of (i) N,N-dimethylformamide (DMF) and (ii) N,N-dimethylacetamide (DMA) with a series of halogenated hydrocarbons that were selected to give a wide range of acceptor properties. Solid 1:1 intermolecular compounds were identified from solutions of (i) DMF and (ii) DMA with CCl_4, CBrCl_3, and C_6H_5CCl_3. The intermolecular compounds (DMF)_2•CCl_4 and (DMF)_2•CBrCl_3 were also found. The results suggest charge transfer from DMF or DMA to the chlorine atoms of the acceptor molecule as the process for compound formation. Thermal methods were used to determine with high precision the solid-liquid …
A Calorimetric Study Of Metal Ion Cyclic Polyether Interaction :|Bi. Cation Binding Properties Of Macrocyclic Polyethers In Aqueous Solution As A Function Of Temperature ; Ii. Effect Of Solvent Dielectric Constant On The Binding Properties Of Cyclic Polyethers For Na[Superscript +] And K[Superscript +], Dennis Pershing Nelson
Theses and Dissertations
The complexation properties of the two isomers of the cyclic polyether dicyclohexyl-18-crown-6 are examined in aqueous solution for a series of metal ions at various reaction temperatures. The results are discussed in terms of size relationships and salvation characteristics of both polyether and metal ions. ΔCp° values are determined from the temperature dependence of the ΔH° values. A discussion of the errors involved in the determination of ΔH° from the temperature dependence of log K values is also included. Comparisons are made between the results of this study and those of a similar study by H. K. Frensdorff, E. I. …
The Roles Of Chlorine Azide In Chemical Lasers, Walter Wood Rice
The Roles Of Chlorine Azide In Chemical Lasers, Walter Wood Rice
Theses and Dissertations
ClN_3 was photolyzed in various gas mixtures to transform its chemical energy into laser radiation. Reaction mechanisms, energy distribution in reaction products, and relative reaction rates were deduced from the laser emission. Flash photolysis of ClN_3-H_2 mixtures produced HCl laser emission; however, due to a narrow range of operating conditions and many competing reactions, the laser output was less than that obtained from comparable Cl_2-H_2 mixtures. The rate constants for H + ClN_3 —> HCl* (v=n) + N_3 were determined to be 0.45 ± 0.05 of the corresponding rate constants for H + Cl_2 —> HCl* (v=n) + Cl. Chlorine …
Eutrophication Of Small Lakes, Lynn T. Kenison
Eutrophication Of Small Lakes, Lynn T. Kenison
Theses and Dissertations
An estimate was made to determine the amount of nitrate and phosphate entering Utah Lake in 1968. To make this estimate, the flow data for 1968 and the nitrate and phosphate concentrations for 1970 were used. This was done because of the lack of information. The results show that the total nitrate added to Utah Lake in 1968 was 7,638,000 pounds. The total phosphate added was 1,740,200 pounds. Of this amount, 12,4 per cent of the nitrate and 18.0 per cent of the phosphate was released from the lake through the Jordan River. The rest remained in the lake to …
Solid-Liquid Phase Equilibria Of The Potassium-Rubidium And Rubidium-Cesium Alloy Systems, Elisabeth M. Delawarde
Solid-Liquid Phase Equilibria Of The Potassium-Rubidium And Rubidium-Cesium Alloy Systems, Elisabeth M. Delawarde
Theses and Dissertations
Thermal methods of high precision were used to determine the solid-liquid phase equilibria diagrams for the potassium-rubidium and the rubidium-cesium systems. Both form minima in the liquidus curves occurring at 307.00° K with 0.667 mole fraction rubidium in the potassium-rubidium system and 282.85° K with 0.530 mole fraction cesium in the rubidium-cesium system. In the potassium-rubidium system, the liquidus and solidus points are very close together, giving a very narrow temperature range for the two phase region. The freezing point minimum in the potassium-rubidium system occurs at 0.667 mole fraction rubidium, suggesting the possible formation of a KRb2 intermetallic compound.
High-Pressure Phase Studies On Sodium–Potassium Alloys, D. Ray Anderson, J. Bevan Ott, Rex J. Goates, H. Tracy Hall
High-Pressure Phase Studies On Sodium–Potassium Alloys, D. Ray Anderson, J. Bevan Ott, Rex J. Goates, H. Tracy Hall
Faculty Publications
The solid–liquid phase diagrams were investigated to 60 kbar for elemental sodium, potassium, and various sodium–potassium alloys. The data for Na and K are in general agreement with those of earlier workers. In the alloy system the temperatures of both the peritectic and eutectic halts increase as the pressure increases, but with different slopes, so that the two invariant points merge at approximately 35 kbar. Above this pressure, two halts are again observed. One increases with increasing pressure, and the other decreases with increasing pressure up to 55 kbar, where it abruptly starts increasing again. Melting points for samples in …
The Effects Of Various Treatments On Thiamin Diphosphate And Total Thiamin Levels Of Rat Tissues, Dong Hwa Park
The Effects Of Various Treatments On Thiamin Diphosphate And Total Thiamin Levels Of Rat Tissues, Dong Hwa Park
Theses and Dissertations
Tissue thiamin diphosphate was assayed enzymatically utilizing purified brewer's yeast apotransketolase. With this assay ten uumoles of thiamin diphosphate could be detected. Total thiamin was fluorometrically measured. For one to three days rats were placed under conditions of stress, consisting of loud noise treatment, emotional stress, deprivation of paradoxical sleep, and swimming to exhaustion, respectively. The body weight was markedly decreased at the end of the respective experimental periods except with the loud noise treated group, compared with the corresponding controls. Following two to three such consecutive treatments, the adrenal weight also showed a significant increase. Thiamin diphosphate and total …
The Chemistry Of Dehydronaphthalene, Richard Harold Hales
The Chemistry Of Dehydronaphthalene, Richard Harold Hales
Theses and Dissertations
The reaction of monohalonaphthalenes with potassium t-butoxide in a t-butyl alcohol-dimethyl sulfoxide (DMSO) mixture has been studied. The 1-bromonaphthalene reaction was extensively studied. Fifteen identifiable products were observed and conditions were found where the desired products, 1- and 2-t-butyl naphthyl ethers (V and VI) were formed in maximum yield, and their decomposition products, 1- and 2-naphthol (XIV and XV), were formed in minimum yield. The mole percent ratio of 1-substituted products (V and XIV) to 2-substituted products (VI and XV) was found under standardized conditions to be 0.35 ± 0.03 in every case when the halogen was I, Br and …
Preparation Of New Amino-, Thio-, And Sulfonyladamantane Derivatives, Joseph Craig Argyle
Preparation Of New Amino-, Thio-, And Sulfonyladamantane Derivatives, Joseph Craig Argyle
Theses and Dissertations
Various synthetic schemes were used to prepare a number of new amino-thio- and sulfonyladamantane compounds. By a nucleophilic substitution on 1-bromoadamantane, 1-(p-nitrophenylthio)adamantane was prepared from p-nitrothiophenol; the amino- and sulfonyl- derivatives of this compound were also prepared. Silver tosylate was used to generate the 1-adamantyl carbonium ion from 1-bromoadamantane in a synthetically useful procedure for preparing 1-adamantylamides from nitriles. Three 1-(1-adamantylcarbinyl)-2,5-dialkylpyrroles were prepared by Knorr-Paal reactions and reduced to the corresponding pyrrolidines. Thio- and aminomethyl 1-adamantyl ketones were prepared from methyl and bromomethyl 1-adamantyl ketones, respectively. Aliphatic and aromatic oxiranes were reacted with 1-aminoadamantane in a bomb at elevated temperatures …
The Reactivity And Selectivity Of The Reaction Of Sulfur Trioxide And Bromobenzene, Sullivan E. Blau
The Reactivity And Selectivity Of The Reaction Of Sulfur Trioxide And Bromobenzene, Sullivan E. Blau
Theses and Dissertations
The sulfonation of bromobenzene with sulfur trioxide in liquid sulfur dioxide at -12 to -13° C. was studied to determine its relative reactivity. The relative rate constant ratio, kbenzene/kbromobenzene, was found to be 28.6 in a competitive reaction between benzene and bromobenzene. The isomer distribution was found to be 0.15 ± 0.02% for the meta, 0.91 ± 0.04% for the ortho and 98.93 ± 0.14% for the para isomers. The partial rate factors were calculated to be pf= 0.208, of= 0.0096 and mf = 0.00018. The relative rate data exhibited a distinctive behaviour previously noted in related systems, possibly due …
High Pressure Spectral Chemistry Of Selected Organic Compounds, Frank William Linsley
High Pressure Spectral Chemistry Of Selected Organic Compounds, Frank William Linsley
Theses and Dissertations
The series of compounds indicated by the formular C_6H_5-(CH=CH)n-C_6H_5 change in color from white (colorless) to yellow to orange to red to deep red as n increases from 1 to 12. Stilbene is the first compound of this series (n=1). Under pressure, exerted by a diamond anvil press, stilbene can be seen to change color from white to yellow to red as increasing pressure is applied. Similar color changes are observed for the compounds where n=2,3, and 4 when subjected to similar pressure. This study records and reports the spectra versus pressure for these compounds.
The Synthesis And Properties Of New Potentially Chemotheraputic [Sic] Pteridine Derivatives, Walter Wesley Parish
The Synthesis And Properties Of New Potentially Chemotheraputic [Sic] Pteridine Derivatives, Walter Wesley Parish
Theses and Dissertations
A new general synthetic method for the preparation of 6-thiopteridines has been developed. The method involves the addition of thiols to intermediate pyrimidine nitrones formed in situ by the reaction of 4-amino-5-nitrosopyrimidines with pyridinium-activated acetonitriles, acetates, acetophenones, and other methylketones. Ca. forty new pteridines were prepared by this method. The preparation of six new 6-pteridinyl ketones, two new 6- pteridinyl ketone thiosemicarbazones, and two new 6-sulfonylpteridines and their 4-acetamido derivatives is also reported. 4-Acetamido-2- amino-7-phenylpteridine 5-oxide was prepared by the reaction of 2- amino-4,6-diacetamido-5-nitrosopyrimidine with either phenylsulfonyl-acetophenone or phenacylpyridinium bromide. Evidence relating to the structure of the acylated 4-amino-5- nitrosopyrimidines …
Donor Properties Of Dimethylsulfoniumcyclopentadienylide And Tetramethylenesulfoniumcyclopentadienylide In Metal Complexes ; Part Ii. The Attempted Preparation Of Boron Tricyanide, Gary Scott Barney
Theses and Dissertations
Part I.--Complexes of dimethylsulfoniumcyclopentadientylide and tetramethylenesulfoniumcyclopentadienylide with metal ions were studied in order to determine the coordination site on the ylids. Infrared spectra indicate that the ylids are coordinated through the cyclopentadienyl ring in all complexes except for the Hg(CN)2 complexes. Coordination-of the HgI2, CdI2, ZnCl2, and AgNO3 complexes is through the number one position on the ring as suggested by NMR data. Infrared and NMR data strongly indicate that the ylids in the Hg(CN)2 complexes are coordinated through sulfur. Part II.--The only method given in the chemical literature for the preparation of boron tricyanide could not be duplicated in …
Asymptotic Evaluation Of Wkb Matrix Elements. Ii. Use Of Langer's Uniform Asymptotic Wavefunctions, Wesley D. Smith, Russell T. Pack
Asymptotic Evaluation Of Wkb Matrix Elements. Ii. Use Of Langer's Uniform Asymptotic Wavefunctions, Wesley D. Smith, Russell T. Pack
Faculty Publications
An improvement in a previous procedure for the analytic asymptotic evaluation of integrals arising in the quantum-mechanical theory of inelastic molecular collisions is presented. The integrals are evaluated using Langer's uniform asymptotic wavefunctions and the higher-order saddle-point or steepest-descents method. It is found that the Langer functions give no better results than WKB functions, but the higher-order steepest-descents corrections produce a marked improvement. The result is a simple method for evaluating a large class of integrals with an error of 0.1%-2.1%.
Quasilattice Interpretation Of The Thermodynamic Properties Of Mixing Of Binary Alkali-Metal Systems, J. Bevan Ott, J. Rex Goates
Quasilattice Interpretation Of The Thermodynamic Properties Of Mixing Of Binary Alkali-Metal Systems, J. Bevan Ott, J. Rex Goates
Faculty Publications
Quasilattice theory was applied to heats of mixing in the six systems formed from the binary combinations of Na, K, Rb, and Cs. The alkali-metal systems are particularly well suited for a critical test of the quasi-crystalline assumption since the theoretical model for these systems is relatively simple and the thermodynamic data are fairly complex. Very good fits of the heat-of-mixing data were achieved by assuming that the larger atom in the binary system covered multiple sites on the quasilattice. The values of the empirically determined constants appear to fit the physical significance accorded to them by the quasilattice model. …
Estimations Of The Effective Electrolytic Surface Area Of Rough And Porous Silver Electrodes ; Ii. Potentiostatic Oxidation Of Silver In Alkaline Electrolyte, James Glenn Bearss
Estimations Of The Effective Electrolytic Surface Area Of Rough And Porous Silver Electrodes ; Ii. Potentiostatic Oxidation Of Silver In Alkaline Electrolyte, James Glenn Bearss
Theses and Dissertations
This dissertation is written in two sections. The first section deals with the development of methods for the estimation of the effective electrolytic surface area of rough and porous silver electrodes in alkaline electrolyte. Data are presented comparing the results of three different methods of surface area estimation. Model pore electrodes were also prepared and oxidized to study the reactions in a pore. Data for constant current oxidations of these electrodes is given. The second section deals with the potentiostatic oxidations of silver in alkaline electrolyte. Data are presented on the total charge acceptance versus applied potential for a potential …
Solid-Liquid Phase Equilibria Of The Sodium-Rubidium And Sodium-Potassium-Rubidium Alloy Systems, Chen-Chao Hsu
Solid-Liquid Phase Equilibria Of The Sodium-Rubidium And Sodium-Potassium-Rubidium Alloy Systems, Chen-Chao Hsu
Theses and Dissertations
Thermal methods were used, to determine with high precision, the solid-liquid phase equilibria diagrams for the sodium-rubidium and sodium-potassium-rubidium systems. In the sodium-rubidium system, the results differ greatly from those of earlier works, especially near the eutectic composition where differences in freezing points as large as 25°K occur. A detailed search was made for possible intermetallic compounds (especially Na2Rb). Neither slow temperature cycling in the temperature range where compound formation could occur nor extended periods of annealing just above the eutectic temperature produced any evidence for compound formation in the sodium-rubidium system. A 2:1 (sodium to rubidium) sample was subjected …
The Catalytic Hydrogenation Of Benzodiazines.|Ni.|Pphthlazine.|Nii.|Pquinazoline, Danny Lee Elder
The Catalytic Hydrogenation Of Benzodiazines.|Ni.|Pphthlazine.|Nii.|Pquinazoline, Danny Lee Elder
Theses and Dissertations
Quinazoline and phthalazine were hydrogenated at low pressure and temperature (60 psi, room temperature) and high pressure and temperature (2000 psi, 100°C, 150°C} in neutral and acidic solvents over 5% Pd/C, 5% Ru/C, 5% Rh/Al2O3 , 5% Rh/C, and 5% Pt/C. Chromatographic methods for determining the qualitative and quantitative composition of hydrogenation mixtures were developed. The compositions of quinazoline and phthalazine-hydrogenation mixtures were determined. Eight phthalazine-hydrogenation products were detected and isolated: (1) 1,2-dihydrophthalazine, (2) 1,2,3,4-tetrahydrophthalazine, (3) a,a'-diamino-o-xylene, (4) o-methylbenzylamine, (5) 1,3-dihydroisoindole, (6) o-xylene, (7 and 8) cis- and trans- 1,2-dimethylcyclohexane. These products were identified by isolating them from reaction mixtures …
Thermodynamics Of Proton Dissociation And Metal Ion Complexation In Aqueous Solution. I, Cation Binding With Cyclic Polyethers: Significance In Ion Transport Processes. Ii, Proton Dissociation From Adenosine, Several Monosaccharides And Related Compounds. Iii, Proton Dissociation From Several Pyrimidines And Their Nucleosides At 10, 25 And 40°, Joseph Howard Ryttling
Theses and Dissertations
The log K, ΔH° and ΔS° values for the interaction of several metal ions with the two isomers of the cyclic polyether, 2,5,8,15,-18,21 hexaoxatricyclo[20.4.0.0^9,14]hexacosane are reported. The stability order found for alkali metal ion interaction with either isomer is identical to the order of ion permeability through reconstituted biological membranes for structurally related antibiotics. The size of the metal ion is critical in determining the extent of interaction. A calorimetric titration study of proton ionization from several monosaccharides and derivatives, pyrimidine bases and their nucleosides, adenosine and its derivatives, and cycloheptaamylose is described. The heats of reaction obtained in this …
A Thermodynamic Approach To The Study Of Phase Equilibria In The Sodium-Potassium Alloy System I. The Phase Diagram For Nak At Atmospheric Pressure ; Ii. High Pressure Phase Studies, Donald Ray Anderson
A Thermodynamic Approach To The Study Of Phase Equilibria In The Sodium-Potassium Alloy System I. The Phase Diagram For Nak At Atmospheric Pressure ; Ii. High Pressure Phase Studies, Donald Ray Anderson
Theses and Dissertations
Ultra-pure reagents, platinum resistance thermometry and modern inert atmosphere glove box facilities have made possible a detailed examination of the NaK system at atmospheric pressure. A thermoanalytical study of solid-liquid phase equilibria in the NaK alloy system was conducted in the tetrahedral press to 55 kbars to investigate possible intermediate compound formation and shifting of the invariant points at various pressures. An expected shift in the eutectic composition to lower potassium content with an increase in the halt temperature on increasing pressure was confirmed. A merging of the meritectic and eutectic points at 343 ±2°K and 37 ±3 kbars occurred …
Mechanism Of Water Transport Through Reverse Osmotic Membranes, Cheryl Kay Murphy
Mechanism Of Water Transport Through Reverse Osmotic Membranes, Cheryl Kay Murphy
Theses and Dissertations
Cellulose acetate membranes show a higher permeability to water than to salt and are being used for desalination of salt water by reverse osmosis. Use of highly acetylated cellulose membranes give a higher salt rejection but also decrease flow rate of the water. The addition of very-short-chain substances or alkyl groups larger than one carbon atom to the cellulose membrane also decreases water flux. A proposed mechanism of transport through the membrane is that the water molecule is passed along the chain by hydrogen bonding with the acetyl groups, The NMR shows a change in the chemical shift of water …
Syntheses Via Modifications Of The Knorr-Paal Procedure :|Ba. Derivatives Of 2,6-Dioxa-10-Azatricyclo[5.2.1.0[Superscript 4,10]]Decane ; B. Highly Sterically Crowded 1,2,5-Trialkylpyrroles And Pyrrolidines, Weldron Severin Burnham
Syntheses Via Modifications Of The Knorr-Paal Procedure :|Ba. Derivatives Of 2,6-Dioxa-10-Azatricyclo[5.2.1.0[Superscript 4,10]]Decane ; B. Highly Sterically Crowded 1,2,5-Trialkylpyrroles And Pyrrolidines, Weldron Severin Burnham
Theses and Dissertations
Earlier work in these laboratories on the heterotricyclic system 2,6-dioxa-10-azatricyclo[5.2.1.04,10]-decane, formed from 1,4-diketones and 2-amino-1,3-propanediols by a product-water-azeotroping procedure, was extended with the synthesis of analogous compounds, e.g., the 1,4,7-triethyl-, 1,7-dimethyl-4-isopropyl-1,7-diethyl-4-isopropyl-, 1,7-dimethyl-3- and 4-phenyl- compounds. The 1,7-dimethyl heterotricycle, the kinetically-controlled product, was accompanied by the thermodynamically-controlled product, 2-(2,5-dimethyl-1-pyrryl)-1,3-propanediol. The 1,7-diethyl heterotricycle was also accompanied by the isomeric pyrrole as were the 1,7-dimethyl-3- and 4-phenyl compounds. A scheme postulating a common intermediate is presented. The interesting analogous compounds, 1,7-dimethyl-2-oxa-6-thia-10-azatricyclo[5.2.1.04,10]decane, 1,4,7-trimethyl-2,6-dioxa-11-azatricyclo[5.3.1.04,11]undecane and 11-hydroxymethyl- and 11-methyl-9,13-dioxa-14- azatetracyclo[6.5.1.02,7 011,14]tetradeca-2,4,6-triene were also prepared. The syntheses in good yields of a considerable number of moderately to …