Dissertations / Theses on the topic 'Oxime ethers'
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1
Laurent, Pierre. "Asymmetric synthesis using chiral oxime ethers." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248161.
2
Hunt, James Charles Atlee. "Chiral oxime ethers in asymmetric synthesis." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302639.
3
Lightfoot, Andrew Philip. "Chiral oxime ethers : applications in synthesis." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/28182.
Abstract:
Chapter One reviews the literature, discussing the role of nucleophilic additions to oximes and their derivatives. This introduction is primarily concerned with the formation of new carbon–carbon bonds, this is achieved by the addition of organometallic reagents to the carbon–nitrogen double bond functionality of oximes and their derivatives.
4
Cooper, Tracey Sara. "Synthesis of amino acids from chiral oxime ethers." Thesis, University of Exeter, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432786.
5
Allcock, Sylvia J. "The Diels-Alder reactions of unsaturated oxime ethers and acyl hydrazones." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303094.
6
Idris, Musa A. "Stereoselective addition reactions of diethylzinc with nitrones, imines and oxime o-ethers." Thesis, University of Sussex, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341803.
7
Acord, Douglas A. "The synthesis and study of 5-oxime-2-methoxy-1,3-xylyl-18-crown-5." Muncie, Ind. : Ball State University, 2009. http://cardinalscholar.bsu.edu/634.
8
Leutzow, Juliane Linda [Verfasser]. "Rhodium-Catalyzed [2+2+2] Cycloaddition of Oxime Ethers and Diynes and Synthetic Approaches Towards a Novel Benzoquinolinone Alkaloid / Juliane Linda Leutzow." Konstanz : Bibliothek der Universität Konstanz, 2015. http://d-nb.info/1088797350/34.
9
Sutherland, Courtney M. "Poly(Arylene) Ethers Prepared From Functionalized 3,5-Difluorotriphenylphosphine Oxide." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341862470.
10
Bragnier, Nicolas. "Synthèse de C-glycosyl amino-acides par voie radicalaire." Paris 11, 2006. http://www.theses.fr/2006PA112261.
11
Harbach, Christopher A. J. "Nitric oxide mediated high selectivity ethene epoxidation." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316731.
12
Tas, Huseyin. "Coordination Polymerization Of Cyclic Ethers By Metal Xanthates And Carbamates." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1225028/index.pdf.
Abstract:
Zinc xanthates are active catalysts in stereoregular polymerization of propylene oxide and markedly more stable than that of known classical stereoregular catalysts. But steric control of zinc xanthates is weaker. To find more effective catalyst systems the isopropyl xanthates of Cu, Pb, Ni, Fe, Al and Sn are investigated and only copper (Cu(isoPr)Xt) and tin (Sn(isoPr)Xt) isopropyl xanthates were appeared to be active, but Cu(isoPr)Xt yielded only low molecular weight product. Therefore Sn(isoPr)Xt system was investigated in detail in polymerization of propylene oxide (PO). Polymerization of PO with this catalyst produced two contrasting polymershigh molar mass, crystalline (K-polymer) and low molar mass (D-polymer). Formation of double bonds in D-polymer was thought to be due to as an anionic process. Polymerization reactions were studied by changing polymerization conditions and reacting catalyst with predetermined amount of water. It&
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s found that Sn(isoPr)Xt have considerably low efficiency than that of Zn(isoPr)Xt catalyst. The yield linearly increases by increasing catalyst concentration. The propagation is competed by termination or transfer process hence overall activation energy is negative. Some mechanistic features of this system was also discussed. The catalytical activity of carbamates in this field has also been reported, without any information about catalytical efficiency and stereoregularity of the process. Therefore zinc diethyl dithiocarbamate was also studied and found as an active catalyst in stereoregular polymerization but it showed weaker efficiency in the PO polymerization than that of Zn(isoPr)Xt catalyst (about 12 times weaker).
13
Narang, Gurtej Singh. "Synthesis and Characterization of Novel Pol(arylene ethers) for Gas Separation and Water Desalination Membranes." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/95968.
Abstract:
This thesis focuses on the synthesis and characterization of various poly(arylene ether)s to improve the efficiency of gas separation and water desalination membranes. This class of polymers includes polymers such as poly(arylene ether sulfone), poly(arylene ether ketone) and poly(phenylene oxide) which offer excellent thermal and mechanical stability and usually have high enough rigidity to support gas separation and water desalination operations. Besides the plethora of properties offered by the homopolymers, these polymers can also be post-modified to cater to specific needs. For example, the polyphenylene oxides have been brominated to increase the permeability for gas separation applications. Blending is another viable method to impart desirable properties to polymers.
Bisphenol A based poly(arylene ether ketone) (BPAPAEK) has been blended with commercially available poly(2,6-dimethylphenylene oxide)s (PPO) of different molecular weights in a fixed ratio (66/34 wt/wt) and in various ratios of a 22000 g/mol PPO. All the blends were UV crosslinked to minimize plasticization by condensable gases and analyzed for gel fractions, whereas, only the 22,000 g/mol blends were tested for transport properties since they yielded the highest gel fractions and exhibited the best mechanical properties. The crosslinking reduced the free volume and improved the selectivity with some drop in permeability. The blends with 90% of the 22000 g/mol PPO by weight was plotted closest to the upperbound.
A phosphine oxide based poly(arylene ether ketone) (POPAEK) was blended with the various PPOs in a similar manner. The results were compared to the BPAPAEK based blends in terms of miscibility behavior and transport properties. It was found that the POPAEK based blends had higher permeability due to the higher fractional free volumes of the POPAEK. The POPAEK was more compatible with the PPOs than BPAPAEK as seen by analyzing various blend permeability models, mechanical properties and scanning electron microscope images. Moreover, blends with both the PAEKs displayed only a small drop in mechanical properties, such as the Young's modulus and the yield strength in comparison to the parent polymers.
Hydroquinone based poly(arylene ether sulfone) oligomers were synthesized, post-sulfonated and chemically crosslinked to determine the effect of water uptake, fixed charge concentration and block length of oligomers on the salt permeability and the hydrated mechanical properties of the networks. The sulfonic acid groups were placed strategically and quantitatively on the hydroquinone units. The strategic placement of the acid groups may help in maintaining high rejection of monovalent ions in the presence of divalent ions, as shown in unpublished work by our group. It was found that the water uptake and fixed charge density had the opposite effects on the salt permeability. Also, the salt permeability varied differently for 5000g/mol and 10000g/mol block based networks.
Another polymer that was investigated in this thesis was poly(2-ethyl-2-oxazoline) (PEtOx). An elaborate account of synthesis of monofunctional, heterobifunctional and telechelic poly(2-ethyl-2-oxazoline)s using different initiators including methyl triflate, activated alkyl halides (e.g., benzyl halides), and non-activated alkyl halides has been presented in this thesis. Endgroup functionalities and molecular weight distributions were studied by SEC, 1H NMR and titrations. The oligomers initiated with the benzyl or xylyl chloride had a PDI of 1.3-1.4 which is broader than expected for a living cationic ring opened polymer. This was attributed to the participation of covalent species which propagated slowly in the activated halide reactions. These oligomers were quantitatively terminated as proven by NMR and titrations. Due to the molecular weight distributions and quantitative termination these oligomers were deemed to be desirable for drug delivery applications.PHD
14
Kursawe, Ansgar. "Partial Oxidation of Ethene to Ethylene Oxide in Microchannel Reactors." Doctoral thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-60728.
Abstract:
In der vorliegenden Arbeit wurde die heterogen katalysierte Oxidation von Ethen zu Ethylenoxid an Silberkatalysatoren untersucht. Ziel dieser Arbeit war es, Mikrostrukturreaktoren für schnelle und stark exotherme Oxidationsreaktionen zu erproben und diese Epoxidation diente als Modellreaktion. Gleichzeitig wurden explosions- und flammhemmende Eigenschaften des Mikrostrukturreaktors ausgenutzt, um die partielle Oxidation von Ethen zu Ethyenoxid im Explosionsbereich (> 9% Sauerstoff) ohne Sicherheitsprobleme zu ermöglichen.
Um die gesteckten Ziele zu erreichen wurden zwei parallele Lösungswege beschritten. Zunächst wurden modulare Mikrostrukturreaktoren und geeignete mikrostrukturierte Katalysatorträger entwickelt, um Untersuchungen verschiedener katalytischer Beschichtungen in dieser neuen und nicht allgemein verfügbaren Reaktorbauweise zu ermöglichen. Zur katalytische Erprobungen dieser Konstruktion war es notwendig, geeignete Beschichtungstechniken zur Immobilisierung katalytisch aktiver Spezies zu entwickeln. Durch die Bauweise dieser Reaktoren als Wandreaktor erschien es anfänglich nicht möglich, kommerziell verfügbare pellet-artige Katalysatoren zu verwenden.
Daher wurden, parallel zur Konstruktion der modularen Mikroreaktoren, verschiedene auf Silber basierende Beschichtungstechniken hinsichtlich ihrer Eignung für diese Reaktion erprobt. Zur Erprobung kamen u.a. Silberimmobilisierung in einem durch anodischen Oxidation erzeugen Porensystem bzw. einer durch Sol-Gel Beschichtung erzeugten a-Aluminiumoxid Schicht und die Abscheidung von metallischem Silber per Vakuumbeschichtung auf einem Trägermaterial. Zuletzt wurde die Immobilisierung eines gemahlenen, kommerziellen Katalysators per elektrostatischer Pulverabscheidung auf einem entsprechend präparierten Trägermaterial vorgenommen und erfolgreich erprobt.
Die wichtigste Erkenntnis dieser Arbeit aus chemisch-katalytischer Sicht ist der enorm positive Einfluss hoher Sauerstoffkonzentrationen auf die Selektivität und gleichzeitig den Umsatz des umzusetzenden Ethylens. Wird die Sauerstoffkonzentration von unter 10% auf bis zu 80% erhöht, so steigt die Selektivität zu Ethylenoxid um ca. 10% an und simultan kann der Umsatzgrad abhängig vom Katalysator und der Reaktortemperatur um den Faktor 2 bis 10 gesteigert werden. Diese Beobachtung wurde für jeden funktionierenden Katalysator gemacht, unabhängig von dessen Herstellung. Mittels Promotoren wie Cs-Salzen und Stickoxiden konnte die Selektivität in Abwesenheit gängiger Moderatoren wie Chlorkomponenten auf 70% (Cs-Salze) bzw. 75% (NOx) gesteigert werden.
Verfahrenstechnisch ist festzuhalten, dass Mikrostrukturreaktoren gleich welcher Bauweise unter allen Reaktionsbedingungen thermisch stabil und beherrschbar blieben. Es wurden Umsatzgrade bis 99% bezüglich Ethen erzielt bzw. Reaktionstemperaturen von über 630 K bei einem binären Ethylen-Sauerstoff Gemisch (20%/80%) angewendet. Angesichts adiabater Temperaturerhöhungen von mehr als 3000 K konnte dennoch ein stabiler Betrieb des Reaktors festgestellt werden. Diese thermische Stabilität war bei Katalysatoren in Festbettreaktoren nicht gegeben.
15
Hibino, Takashi, Atsuko Tomita, Mitsuru Sano, Masahiro Nagao, Kohsuke Okamoto, Takanori Kawai, and Masaya Yano. "Single-Chamber SOFCs Using Dimethyl Ether and Ethanol." The Electrochemical Society, 2007. http://hdl.handle.net/2237/18431.
16
Meyer, Luke. "Structure-Property Relationships of N-Heterocycle Functionalized Triphenylphosphine Oxide-Based Poly (Arylene Ether)s." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright154651093060725.
17
Yenne, Samuel P. "Investigations on the mechanism of action of the oxime ether safeners for the protection of grain sorghum against metolachlor." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54821.
Abstract:
Herbicide safeners (protectants, antidotes) are used to protect crop plants from herbicide injury. Currently our understanding of the mechanisms involved in the protection of plants by safeners is not well defined; therefore, investigations were conducted to elucidate the mechanism(s) of action of the oxime ether safeners. Molecular comparisons of selected herbicide-safener combinations using computer-aided molecular modeling revealed that the chemical structures of safeners and herbicides are very similar at the molecular level; and, indicate that these compounds could bind at the same active site of the target protein or they may serve as inducers of metabolic enzymes which detoxify herbicides. Metolachlor at 10 μM and seed-applied CGA-133205 had no effect on germination while treatment with seed-applied oxabetrinil significantly reduced germination of grain sorghum. Results from experiments on ¹⁴C-acetate incorporation into lipids indicate that metolachlor and the oxime ether safeners influence lipid metabolism causing a redistribution of carbon in the lipid fractions of germinating sorghum roots. Results from studies with acetyl-CoA carboxylase indicate that this enzyme is not a target site for either metolachlor or the oxime ether safeners. Metolachlor and the oxime ether safeners enhanced glutathione levels in grain sorghum seedlings at 12 to 48 hr after imbibition was initiated with oxabetrinil being more stimulatory than metolachlor or CGA-133205. Glutathione reductase activity was also stimulated in safener-treated grain sorghum seedlings. Both safeners slightly enhanced nonenzymatic and enzymatic conjugation of metolachlor with reduced glutathione. Oxabetrinil conjugated enzymatically or nonenzymatically with reduced glutathione at a slow rate, but CGA-133205 did not. These data suggest that during the early stages of seed germination and seedling development of grain sorghum, safeners can enhance the detoxication of metolachlor by enhancing glutathione levels and enzymatic and nonenzymatic conjugation of metolachlor with glutathione. It appears that oxabetrinil and CGA-133205 are conferring protection to grain sorghum by increasing the rate of metolachlor metabolism.Ph. D.
18
Woods, Georgina Ann. "The adsorption and reaction of model adhesion promoters on metal and metal oxide surfaces." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366512.
19
Khan, Asad Ahmad. "Oxidative dehydrogenation (ODH) of ethane to ethene over supported vanadium containing oxide catalysts." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/91544/.
Abstract:
In this thesis work oxidative dehydrogenation (ODH) of ethane to ethane over MoV oxide catalyst was investigated. The influence of the preparation techniques and different reaction conditions were studied thoroughly. It was found that the precipitation method for the catalyst preparation using variable pH produces a more active catalyst at pH values of 3 to 3.5. Slurry temperature and calcination temperature are also very important parameters which affect the selectivity pattern of the products. This selectivity pattern was found to be further influenced by reaction temperature, pressure, GHSV and ethane-oxygen ratio in the feed. The influence of the V: Mo ratio on the performance of the catalyst for the ODH was investigated by several characterisation techniques, such as BET, XRD, XPS, TEM, SEM, EDX coupled with catalytic performance tests in a fixed bed reactor. The optimum V: Mo ratio was found to be 0.25:1 (i.e., MoV0.40). At this ratio, the oxidation state of vanadium with respect to total vanadium concentration (V5+/Vtotal) is at an optimum in terms of the adsorption strength of the desired products. It was further fine-tuned by investigating the influence of reaction conditions. An improvement on the most active MoV oxide catalyst for the ODH reaction was developed with the addition of oxalic acid as the vanadium dissolution and pH adjustment agent. Addition of oxalic acid influenced the catalytic properties in a variety of ways as observed from characterisation and reaction results. Addition of either a smaller amount or an excess amount compared with the optimal amount has determental impact on the activity of the catalyst. Further catalytic activities were tested by the addition of different types of supports (e.g., ZrO2, TiO2, Nb2O5, SiO2, and AlO3) into the MoV oxide catalytic system. The alumina support was extensively tested with different amounts onto the base MoV oxide for the ethane ODH to ethane.
20
Popham, Michael Charles. "Complexes of Group III metal salts and titanium halides with tertiary pnictogen oxide and crown ether ligands." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274472.
21
Leite, Juliana Aparecida dos Santos. "Síntese de potenciais intermediários de princípios ativos, buscando sempre o emprego de técnicas para proteção do meio ambiente." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/97/97136/tde-02102013-143143/.
Abstract:
A química verde, que tem a preocupação com o desenvolvimento de tecnologias e processos incapazes de causar poluição, tem sido citada cada vez mais em destaque, pela mídia, como mais uma das iniciativas para prevenção da poluição desenfreada. Neste estudo tem-se buscado a redução ou eliminação de solventes, adaptação dos sistemas reacionais para operação em temperatura ambiente e aumento do rendimento em processos de reações guiados pelos doze princípios da química verde. O objetivo deste trabalho consiste na síntese de intermediários de princípios ativos para uso industrial, através de processos de formação de oximas e oximas éteres. O trabalho foi dividido em duas etapas principais, preparação de oximas e preparação de oximas éteres. Na primeira preparou-se oximas através da reação de aldeídos (benzaldeído, furfuraldeído, salicilaldeído e p-anisaldeído) e cetonas (ciclopentanona, ciclohexanona, metil etil cetona, benzofenona e acetofenona) com cloreto de hidroxilamina, sem a utilização de solventes orgânicos e sem adição de água. Na segunda o objetivo foi preparar oximas éteres (O-butil benzaldeído oxima, O-butil furfuraldeído oxima, N-butoxi-(2-butoxifenil) metanimina, O-butil p-anisaldeído oxima, O-butil ciclohexanona oxima, O-butil ciclopentanona oxima e O-butil metil etil cetona oxima) a partir da alquilação de oximas utilizando um suporte sólido de KF/Al2O3 como catalisador. Todos os compostos foram caracterizados por RMN 13C (apt) e alguns por infravermelho e RMN 1H.Green chemistry, which is concerned with the development of technologies and processes incapable of causing pollution, has been cited increasingly highlighted, by the media, as another of the initiatives to prevent pollution rampant. This study has sought a reduction or elimination of solvents, reaction to adjust the systems operating at room temperature and yield increase in reactive processes that are guided by the twelve principles of green chemistry. The objective of this work is the synthesis of active intermediates for industrial use, through processes of formation of oximes, oximes ethers. The work was divided into two phases, preparation of oximes and preparation of oximes ethers. In the first was prepared oximes by reaction of aldehydes (benzaldehyde, furfuraldeyde, salicylaldehyde and p-anisaldeyde) and ketones (cyclopentanone, cyclohexanone, methyl ethyl ketone, benzophenone and acetophenone) with hydroxylamine chloride without the use of organic solvents and without adding water. For the second was prepared oximes ethers (O-butyl benzaldheyde oxime, O-butyl furfuraldeyde oxime, N-butoxy-(2-butoxyphenyl) methanimine, O-butyl p-anisaldeyde oxime, O-butyl cyclohexanone oxime, O-butyl cyclopentanone oxime e O-butyl methyl ethyl ketone oxime) from the alkylation of oximes, using a solid support as catalyst KF/Al2O3. All compounds were characterized by 13C NMR (apt) and some infrared and 1H NMR.
22
Ozturk, Elif. "Copolymerisation Of Carbon Disulfide, Carbon Dioxide And Other Carbonic Acid Derivatives With Cyclic Ethers By Using Metal Xanthate Catalysts." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607227/index.pdf.
Abstract:
The synthesis of high molecular weight copolymer of carbon disulphide (CS2) and propylene oxide (PO) has not reported in literature. In the present work, zinc isopropyl xanthate (Zn(Xt)2) was used as catalyst for the copolymerisation of PO and CS2 into high copolymer. However, the product can be fractionated into high and low molecular weight components. High molecular weight copolymer was rubbery products, but low molecular weight copolymers were oily products containing cyclic dithiocarbonates. Copolymers were characterized by elemental, end group analysis, DSC, TGA, GPC, Light Scattering, UV, IR, NMR spectroscopy, polarized microscopy and refractometry.
Copolymerization process was zeroth order with respect to monomers, and its non-terminated but suffered from several types of transfer reactions. As a result of transfer reactions S-(C=S)-S, O-(C=S)-O, O-(C=O)-O groups in the backbone of copolymer and SH groups at the chain terminals and cyclic dithiocarbonates are formed. Apart from SH groups, OH and double bonds were found and their amounts were
determined at the chain terminals. Copolymers with high mole fractions of PO units (F1) in the copolymer are crystallized in the shape of Malta’
s Cross. Melting points of products were obtained from DSC. The F1 values are calculated from elemental analysis as well as zeroth order rate constants and from melting point of the crystals. All three results were in close agreement and changed between 0.9 &
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0.7. However, these ratios depend on reaction conditions (temperature, catalyst and monomer concentrations, time and dielectric constant of reaction medium). A mechanism for coordination-copolymerization on the basis of above observation was proposed.
23
Satpathi, Hirak. "Novel phosphorus containing poly(arylene ethers) as flame retardant additives and as reactant in organic synthesis." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-176136.
Abstract:
Due to their outstanding properties, poly(arylene ethers) are useful as toughness modifiers in epoxy resins (EP). Furthermore, these polymers show rather low intrinsic fire risks. According to recent research it has been incorporated that poly(arylene ether phosphine oxides) [PAEPO’s] can further improve the fire behavior. Increasing phosphorous content of the PAEPO can influence the fire behavior too. Fire retardants containing phosphorus – regardless of whether an additive or reactive approach is used – show different mechanisms in the condensed and gas phase. In the present study PSU Control (BPA based polysulfone) with four different PAEPO’s and their corresponding blends with an EP were investigated.
All poly(arylene ether phosphine oxides) were synthesized by nucleophilic aromatic polycondensation. The polymers obtained covered a wide range of weight average molar masses (6,000 – 150,000 g/mol) as determined by size exclusion chromatography with multi-angle light scattering detection (MALLS). FTIR, NMR spectroscopy and MALDI-TOF revealed formation of the desired polymer structure of the linear poly(arylene ethers). All polymers were easily soluble in common organic solvents, thus enabling processing from solution.The pyrolysis and the fire retardancy mechanisms of the polymers and blends with epoxy resin (EP) were tackled by means of a comprehensive thermal analysis (thermogravimetry (TG), TG-evolved gas analysis) and fire tests [PCFC, limiting oxygen index (LOI), UL-94, cone calorimeter].
The Mitsunobu reaction of Dimethyl-5-hydroxyisophthalate and a long chain semifluorinated alcohol requires triphenyl phosphine as a reactant. Identical, in some case higher yield was obtained in the usual conditions, with triphenyl phosphine and with trivalent phosphorus containing polymers, which was prepared in solvent free bulk (melt) polymerization technique from trivalent phosphorus monomer and a silylated diphenol in presence of CsF. Purification and the recovery of the final product which is always a big challenge in case of Mitsunobu reaction, was far more easier using polymer compared to triphenyl phosphine. During polymerization there was a possibility to have polymer having repeating unit containing both trivalent phosphorus and phosphine oxide. The trivalent phosphorus content of the polymer can be varied using different molar concentration of CsF.
24
Camerino, Eugene. "Fluoromethyl ketone prodrugs: Potential new insecticides towards Anopheles gambiae." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73771.
Abstract:
Malaria continues to cause significant mortality in sub-Saharan Africa and elsewhere, and existing vector control measures are being threatened by growing resistance to pyrethroid insecticides. With the goal of developing new human-safe, resistance-breaking insecticides we have explored several classes of acetylcholinesterase inhibitors. In vitro assay studies demonstrate that tri- and difluoromethyl ketones can potentially inhibit An. gambiae AChE (AgAChE). These compounds inhibit the enzyme by making a covalent adduct with the catalytic serine of AChE. Trifluoromethyl ketones however are poor inhibitors of the G119S resistant mutant of AgAChE. However difluoromethyl ketones can inhibit G119S AgAChE and compound 3-10g showed an IC₅₀ value of 25.1 nM after 23h incubation time. Despite this potent inhibition of AgAChE, the tri-, di-, and (mono)fluoroketones showed very low toxicity to An. gambiae, perhaps due to hydration and rapid clearance.
In an attempt to improve An. gambiae toxicity, oximes and oxime ethers of these compounds were prepared as potential prodrugs. These structures identified trifluoromethyl ketone oxime 3-2d as a potent toxin against both wild-type (G3-strain) and a multiply resistant (Akron) strain of An. gambiae. This compound is within 3-fold of the toxicity of propoxur to wild type An. gambiae (LC₅₀ values of 106 and 39 µg/mL, respectively). Most significantly, 3-2d was much more toxic than propoxur to multiply-resistant (Akron) strain An. gambiae (LC₅₀ = 112 and >5,000 µg/mL, respectively). However, thus far we have not been able to link the toxicity of these compounds to a cholinergic mechanism. Pre-incubation studies suggest that significant hydrolysis of these compounds to TFKs does not occur over 22 h at pH 7.7 or 5.5.
The mechanism of action of 3-2d remains unknown. Our enzyme inhibition studies have demonstrated that 3-2d does not hydrolyze to the trifluoromethyl ketone 2-9d at pH 7.7. The high Akron toxicity of 3-2d and poor inhibition of G119S AgAChE by 2-9d argue against enzyme mediated conversion of 3-2d to 2-9d within the mosquito. Thus, we can rule out an AChE inhibition mechanism for toxicity. Additional experiments by our collaborator (Dr. Jeffrey Bloomquist, University of Florida) also rule out inhibition of mitochondrial respiration or agonism of the muscarinic acetylcholine receptor. Future work will address other potential insecticidal modes of action.Ph. D.
25
Nebipasagil, Ali. "Synthesis and Characterization of Hydrophilic-Hydrophobic Poly (Arylene Ether Sulfone) Random and Segmented Copolymers for Membrane Applications." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/71337.
Abstract:
Poly(arylene ether sulfone)s are high-performance engineering thermoplastics that have been investigated extensively over the past several decades due to their outstanding mechanical properties, high glass transition temperatures (Tg), solvent resistance and exceptional thermal, oxidative and hydrolytic stability. Their thermal and mechanical properties are highly suited to a variety of applications including membrane applications such as reverse osmosis, ultrafiltration, and gas separation. This dissertation covers structure-property-performance relationships of poly(arylene ether sulfone) and poly(ethylene oxide)-containing random and segmented copolymers for reverse osmosis and gas separation membranes.
The second chapter of this dissertation describes synthesis of disulfonated poly(arylene ether sulfone) random copolymers with oligomeric molecular weights that contain hydrophilic and hydrophobic segments for thin film composite (TFC) reverse osmosis membranes. These copolymers were synthesized and chemically modified to obtain novel crosslinkable poly(arylene ether sulfone) oligomers with acrylamide groups on both ends. The acrylamide-terminated oligomers were crosslinked with UV radiation in the presence of a multifunctional acrylate and a UV initiator. Transparent, dense films were obtained with high gel fractions. Mechanically robust TFC membranes were prepared from either aqueous or water-methanol solutions cast onto a commercial UDEL® foam support. This was the first example that utilized a water or alcohol solvent system and UV radiation to obtain reverse osmosis TFC membranes. The membranes were characterized with regard to composition, surface properties, and water
uptake. Water and salt transport properties were elucidated at the department of chemical engineering at the University of Texas at Austin.
The gas separation membranes presented in chapter three were poly(arylene ether sulfone) and poly(ethylene oxide) (PEO)-containing polyurethanes. Poly(arylene ether sulfone) copolymers with controlled molecular weights were synthesized and chemically modified to obtain poly(arylene ether sulfone) polyols with aliphatic hydroxyethyl terminal functionality. The hydroxyethyl-terminated oligomers and α-ω-hydroxy-terminated PEO were chain extended with a diisocyanate to obtain polyurethanes. Compositions with high poly(arylene ether sulfone) content relative to the hydrophilic PEO blocks were of interest due to their mechanical integrity. The membranes were characterized to analyze their compositions, thermal and mechanical properties, water uptake, and molecular weights. These membranes were also evaluated by collaborators at the University of Texas at Austin to explore single gas transport properties. The results showed that both polymer and transport properties closely related to PEO-content. The CO2/CH4 gas selectivities of our membranes were improved from 25 to 34 and the CO2/N2 gas selectivity nearly doubled from 25 to 46 by increasing PEO-content from 0 to 30 wt.% in polyurethanes.
Chapter four also focuses on polymers for gas separation membranes. Disulfonated poly(arylene ether sulfone) and poly(ethylene oxide)-containing polyurethanes were synthesized for potential applications as gas separation membranes. Disulfonated polyols containing 20 and 40 mole percent of disulfonated repeat units with controlled molecular weights were synthesized. Poly(arylene ether sulfone) polyols and α,ω-hydroxy-terminated poly(ethylene oxide) were subsequently chain extended with a diisocyanate to obtain polyurethanes. Thermal and mechanical characterization revealed that the polyurethanes had a phase-mixed complex morphology.Ph. D.
26
Polk, William David. "Polydimethylsiloxane Containing Block Copolymers: Synthesis and Characterization of Alternating Poly(Arylene Ether Phosphine Oxide)-B-Siloxane and Segmented Nylon 6,6 -B-Siloxane Copolymers." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/29968.
Abstract:
Two novel classes of siloxane containing, organic-inorganic block copolymers were prepared using different synthetic approaches. The first copolymers were alternating poly(arylene ether phosphine oxide)-poly(dimethylsiloxane) systems, prepared via oligomeric silylamine-hydroxyl reactions. Secondly, segmented nylon 6,6-poly(dimethylsiloxane) block copolymers were synthesized via a non-aqueous adaptation of the "nylon 6,6 salt" hydrolytic polyamidization, using bis(aminopropyl) dimethylsiloxane oligomer as a co-reactant.
Three series of "perfectly" alternating block copolymers were produced from well characterized hydroxyl-terminated poly(arylene ether phosphine oxide) and dimethylamine-terminated poly(dimethylsiloxane) oligomers, in order to investigate both block length and chemical composition effects. Copolymerization in chlorobenzene resulted in high molecular weight materials capable of forming optically clear, nanophase separated films, which displayed unusual morphologies and good mechanical strength. Thermal gravimetric analysis showed high thermo-oxidative stability and increasing char yield with increasing siloxane content. Additional thermal and mechanical investigations provided evidence of selective phase mixing, particularly at shorter block lengths. Surface analysis showed an enrichment of the siloxane blocks at the air-polymer interface in comparison to the bulk state. This behavior increased in proportion to the length of the parent siloxane oligomers. Evaluation of selected optical properties, e.g., refractive indices, revealed linear trends resulting in values of compositionally weighted averages.
Conversely, a series of nylon 6,6-siloxane copolymers were produced from the polycondensation of preformed propylamine-terminated poly(dimethylsiloxane)s, solid nylon 6,6 salt and a corresponding amount of adipic acid to afford siloxane-amide semi-crystalline copolymers with siloxane content ranging from 10 to ~45 wt%. The characterization of high molecular weight and covalent siloxane-amide linkages was hindered by insolubility. For example, crystallinity of the nylon 6,6 precluded the use of common solution techniques, while the susceptibility of the siloxane blocks towards ionic redistribution prevented the use of strongly acidic solvents. However, development of a novel analytical technique using solid state 13C NMR and liquid-solid extraction provided evidence for the presence of covalent bonding between the dissimilar oligomer chains. Thermal gravimetric analysis of resultant copolymers revealed an increase in char yield with increasing siloxane content, a preliminary indicator of increased fire resistance, which was supported by subsequent qualitative Bunsen burner observations. Differential scanning calorimetry showed retention of the polyamide crystalline melt with levels of siloxane incorporation of up to 45 weight %.
In conclusion, two novel classes of polydimethylsiloxane containing block copolymers have been successfully synthesized, despite the complications created as a result of the polar/non-polar interactions developed between a semi-inorganic polydimethylsiloxane and the hydrocarbon based polyarylene ethers and nylon 6,6.Ph. D.
27
Tanaka, Yohei. "Removal of CO by water gas shift reaction and catalytic production of hydrogen from dimethyl ether over Cu-based spinel-type oxide catalyst." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144925.
Abstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第11580号
工博第2526号
新制||工||1343(附属図書館)
23223
UT51-2005-D329
京都大学大学院工学研究科物質ｴﾈﾙｷﾞｰ化学専攻
(主査)教授 江口 浩一, 教授 井上 正志, 教授 垣内 隆
学位規則第4条第1項該当
28
Kursawe, Ansgar [Verfasser], Dieter [Akademischer Betreuer] Hönicke, Elias [Gutachter] Klemm, and Werner A. [Gutachter] Goedel. "Partial Oxidation of Ethene to Ethylene Oxide in Microchannel Reactors : Partial Oxidation of Ethene to Ethylene Oxidein Microchannel Reactors / Ansgar Kursawe ; Gutachter: Elias Klemm, Werner A. Goedel ; Betreuer: Dieter Hönicke." Chemnitz : Universitätsbibliothek Chemnitz, 2010. http://d-nb.info/1213736226/34.
29
Sypien, Jakub Konrad. "Structure-reactivity relationships in aluminium alkoxides-catalysed co-polymerisation reactions Aluminium 2,2' methylenebisphenoxide in the synthesis of poly(ether-carbonate)s from cyclohexene oxide and carbon dioxide /." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:16-opus-68506.
30
DUMAS, HERBIN CHRISTINE. "Chromatographie en phase liquide et synthese organique, exemple d'un produit industriel : la cylcododecanone oxime." Paris 6, 1987. http://www.theses.fr/1987PA066104.
Abstract:
Les techniques de la chromatographie en phase liquide ont permis de mettre au point une separation optimisee des impuretes de la cyclododecanone oxime. La methode la plus performante est la chromatographie de partage a polarite de phases inversee sur un gel de silice greffee octadecyle avec une phase mobile ayant la composition suivante : methanol-acetonitrile-tetrahydrofurane-eau 33:24:3,5:39,5 (v/v). Une trentaine d'impuretes sont ainsi mises en evidence grace a l'emploi d'une colonne de petit calibre de 1 metre de long et de 1 millimetre de diametre interieur. Cette colonne contient 30000 plateaux theoriques. La duree de la separation est de 3,5 heures. L'identification d'un certain nombre de ces impuretes a ete effectuee par la conjonction de differentes methodes : couplage en ligne avec la spectrometrie de masse et chromatographie semi-preparative permettant d'isoler des quantites notables de certaines impuretes identifiees par la spectrometrie de masse differee de meme on a pu appliquer a ces impuretes la spectrometrie infrarouge par transformee de fourier
31
Shaver, Andrew Thomas. "Advanced Polymeric Membranes and Multi-Layered Films for Gas Separation and Capacitors." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71692.
Abstract:
The following studies describe the synthesis and properties of a family of poly(arylene ether ketone)s which are well known to have good thermal stability, mechanical durability, and other film properties. These poly(arylene ether ketone)s were functionalized with fluorine, oxidized, blended, and crosslinked to increase performance with focus on materials for polymeric capacitors and gas separation membranes.
There is a need for polymeric capacitors with improved energy storage density and thermal stability. In this work, the affect of polymer molecular structure and symmetry on Tg, breakdown strength, and relative permittivity was investigated. A systematic series of four amorphous poly(arylene ether ketone)s was compared. Two of the polymers had symmetric bisphenols while the remaining two had asymmetric bisphenols. Two contained trifluoromethyl groups while the other two had methyl groups. The symmetric polymers had Tg's of approximately 160 °C while the asymmetric polymers showed higher Tg's near 180 °C. The symmetric polymers had breakdown strengths near 380 kV/mm at 150 °C. The asymmetric counterparts had breakdown strengths near 520 kV/mm even at 175 °C, with the fluorinated polymers performing slightly better in both cases. The non-fluorinated polymers had higher relative permittivities than the fluorinated materials, with the asymmetric polymers being better in both cases.
Two amorphous, high glass transition, crosslinkable poly(arylene ether)s for gas purification membranes have been studied. The polymers were polymerized via step growth and contained tetramethyl bisphenol F and either 4,4'-difluorobenzophenone or 4,4'-dichlorodiphenylsulfone. The benzylic methylene group in tetramethyl bisphenol F can undergo oxidation reactions and crosslinking with UV light. The polymers were oxidized under two different conditions, one by chemical treatment using oxone and KBr and one by elevated thermal treatment in air. Thermogravimetric analysis, 1H-NMR and attenuated total reflectance Fourier transform infrared spectroscopy revealed the progress of the thermal oxidation reactions. Both polymers produced tough, ductile films and gas transport properties of the non-crosslinked linear polymers and crosslinked polymer was compared. Crosslinking was performed by irradiating polymer films for one hour on each side in air under a 100W high intensity, long-wave UV lamp equipped with a 365-nm light filter. The O2 permeability of tetramethyl bisphenol F containing non-crosslinked poly(arylene ether ketone) was 2.8 Barrer, with an O2/N2 selectivity of 5.4. Following UV crosslinking, the O2 permeability decreased to 1.8 Barrer, and the O2/N2 selectivity increased to 6.2.
Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is a commercial polymer that is utilized for gas separation membranes. It has a relatively high free volume with high gas permeabilities but suffers from low gas selectivities. In this study, PPO polymers with number average molecular weights of 2000, 6000, 17,000, 19,000 and 22,000 were synthesized and blended with a poly(arylene ether ketone) synthesized from bisphenol A and difluorobenzophenone (BPA-PAEK) to make UV-crosslinkable films. The ketone and benzylic methylene groups on the BPA-PAEK and the PPO polymers respectively formed crosslinks upon exposure to broad wavelength UV light. The crosslinked blends had increased selectivities over their linear counterparts. DSC thermograms showed that the blends with all but the lowest molecular weight PPO had two Tg's, thus suggesting that two phases were present, one high in PBA-PAEK and the other high in PPO composition. The PBA-PAEK blend with the 2000 Mn PPO showed only one Tg between the two control polymers. Despite the immiscibility of these films, the gel fractions after UV exposure were high. Gel fractions as a function of the amount of the 22,000 Mn PPO were explored and did not show any significant change. UV spectroscopy of the individual components and the blends showed that more broad wavelength light was transmitted through the PPO component, so it was reasoned that films that was high in PPO composition crosslinked to deeper depths. The O2/N2 permeabilities and selectivities were measured for the linear and crosslinked films. Between the 33/67, 67/33, and 90/10 22k PPO/BPA PAEK crosslinked blended films, the 90/10 PPO/BPA PAEK gained the most selectivity and maintained a larger amount of its permeability. In comparison to commercial gas separation polymers, the non-crosslinked 33/67 22,000 Mn PPO/BPA PAEK blend outperformed polysulfone and cellulose acetate with a 2.45 degree of acetylation. Overall, we were able to blend a small amount of BPA PAEK with the commercially used PPO to create a mechanically robust crosslinked polymer film.Ph. D.
32
Pandey, Dhurba Raj. "Degradation of Select Chlorinated Hydrocarbons by (i) Sulfide-Treated Hydrous Ferric Oxide (HFO) and (ii) Hydroxyl Radicals Produced in the Dark by Oxygenation of Sodium Dithionite-Reduced HFO." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1535462165887662.
33
Kortsdottir, Katrin. "The Impact of Hydrocarbon and Carbon Oxide Impuritiesin the Hydrogen Feed of a PEM Fuel Cell." Doctoral thesis, KTH, Tillämpad elektrokemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193694.
Abstract:
The proton exchange membrane fuel cell generates electricity from hydrogen and oxygen (from air) through electrocatalytic reactions in an electrochemical cell. The Pt/C catalyst, commonly used in PEM fuel cells, is very sensitive to impurities that can interact with the active catalyst sites and limit fuel cell performance. Unfortunately, most hydrogen is currently produced from fossil sources, and inevitably contains impurities. The subject of this thesis is the effect of hydrogen impurities on the operation of a PEM fuel cell using a Pt/C anode. The impurities studied are carbon monoxide (CO), carbon dioxide (CO2), and selected hydrocarbons. Particular focus is given to the interaction between the impurities studied and the anode catalyst. The main method used in the study involved performing cyclic voltammetry and mass spectrometry, simultaneously. Other electrochemical techniques are also employed. The results show that all the impurities studied adsorb to some extent on the Pt/C catalyst surface, and require potentials comparable to that of CO oxidation, i.e., about 0.6V, or higher to be removed by oxidation to CO2. For complete oxidation of propene, and toluene, potentials of above 0.8, and 1.0V, respectively, are required. The unsaturated hydrocarbons can be desorbed to some extent by reduction, but oxidation is required for complete removal. Adsorption of ethene, propene, and CO2 is dependent on the presence of adsorbed or gaseous hydrogen. Hydrogen inhibits ethene and propene adsorption, but facilitates CO2 adsorption. Adsorption of methane and propane is very limited and high concentrations of methane cause dilution effects only. The adlayer formed on the Pt/C anode catalyst in the presence of CO2, or moderate amounts of hydrocarbons, is found to be insffuciently complete to notably interfere with the hydrogen oxidation reaction. Higher concentrations of toluene do, however, limit the reaction.Polymerelektrolytbränslecellen genererar elektricitet fran vätgas och syrgas (fran luft) genom elektrokatalytiska reaktioner i en elektrokemisk cell. Den platina-baserade katalysator som oftast används i dessa bränsleceller är känslig mot föroreningar, då dessa kan interagera med katalysatorns aktiva yta, och därmed begränsna bränslecellens prestanda. Tyvärr produceras dagens vätgas huvudsakligen fran fossila källor och innehåller därför oundvikligen föroreningar. Denna avhandling behandlar hur olika vätgasföroreningar påverkar katalysatorns aktivitet och bränslecellens drift. De föroreningar som studeras är kolmonoxid (CO) och koldioxid (CO2), samt ett antal mindre kolväten. Störst fokus ligger på hur dessa föroreningar interagerar med anodens Pt/C katalysator. Den metod som huvudsakligen används är cyklisk voltammetri kombinerat med masspektrometri, men flera elektrokemiska metoder har använts. Resultaten visar att alla undersökta föroreningar adsorberar på Pt/C katalysatorns yta i större eller mindre utstreckning. For att avlägsna det adsoberade skiktet genom oxidation till CO2 krävs potentialer jämförbara med CO oxidation, dvs ca 0,6V, eller högre. Fullständig oxidation av propen eller toluen kräver potentialer högre än 0,8V respektive 1,0V. De omättade kolvätena kan delvis avlägsnas genom reduktion, men fullständig avlägsning kräver oxidation. Närvaron av väte, i gasform eller adsorberat pa katalysatorn, hämmar adsorptionen av eten och propen, men främjar CO2 adsorption. Metan och propan adsorberar i mycket begränsad utstreckning på Pt/C katalysatorns yta. De prestandaförluster som uppstår av höga koncentrationer av metan förklaras av utspädning av vätgasen. Det adsorberade skiktet som bildas när Pt/C katalysatorn exponeras för CO2 eller måttliga koncentrationer av studerade kolväten, är inte tillräckligt heltäckande for att märkbart påverka vätgasreduktionen. Däremot kan höga koncentrationer av toluen begränsa reaktionen.
QC 20161010
34
Wiles, Kenton Broyhill. "High Performance Disulfonated Poly(arylene Sulfone) Co- and Terpolymers For Proton Exchange Membranes For Fuel Cell And Transducer Applications: Synthesis, Characterization And Fabrication Of Ion Conducting Membranes." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/27096.
Abstract:
The results described in this dissertation have demonstrated several alternative proton exchange membranes (PEM) for hydrogen-air and direct methanol fuel cells (DMFC) that perform as well or better than the state of the art Nafion perfluorosulfonic acid membrane. Direct aromatic nucleophilic substitution polycondensations of disodium 3,3â S-disulfonate-4,4â S-difluorodiphenylsulfone (SDFDPS), 4,4â S-difluorodiphenylsulfone (DFDPS) (or their chlorinated analogs, SDCDPS, DCDPS) and 4,4â S-thiobisbenzenethiol (TBBT) in the presence of potassium carbonate were investigated. Electrophilic aromatic substitution was employed to synthesize the SDFDPS or SDCDPS comonomers in high yields and purity. High molecular weight disulfonated poly(arylene thioether sulfone) (PATS) copolymers were easily obtained using the SDFDPS monomers, but in general, slower rates and a lower molecular weight copolymer was obtained using the analogous chlorinated monomers. Tough and ductile membranes were solution cast from N,N-dimethylacetamide for both series of copolymers. The degrees of disulfonation (20-50%, PATS 20-50) were controlled by varying the ratio of disulfonated to unsulfonated comonomers. Composite membranes were prepared by homogeneous solution blending the copolymers with phosphotungstic acid (PTA) in dimethylacetamide (DMAc). The composite PATS membranes exhibited moderate PTA molecule water extraction after acidification treatments performed at either room or boiling temperatures. The membranes containing HPA showed improved conductivity at high temperatures (120 ¢XC) and low relative humidities when compared to the pure copolymers.
Molecular weight of the copolymers plays a critical role in the overall copolymer physical behavior. It is well known that molecular weight has an enormous impact on practically all of the physical properties of polymeric systems. This dissertation discusses the influence of molecular weight on the characteristics of a specific family of PEM PATS copolymers. This study elucidated that the lower molecular weight materials did indeed behave differently than the higher molecular weight copolymers. Specifically, the water uptake and permeability to methanol decreased with increasing molecular weight. Furthermore, the fully hydrated mechanical properties also improved with molecular weight.
The synthesis and fabrication of 45 mole percent disulfonated poly(arylene ether phenyl phosphine oxide diphenyl sulfone) terpolymer-heteropolyacid (HPA) composite membranes and membrane electrode assemblies were chosen for detailed investigation. A series of 45 mole percent disulfonated biphenol-based poly(arylene ether phenyl phosphine oxide diphenyl sulfone) terpolymers (BPSH45-PPO) were also synthesized by nucleophilic aromatic substitution polymerizations. The level of disulfonation was constant at 45 mole percent providing a compromise between high conductivity at low humidity and reasonable mechanical properties in liquid water. The amounts of 4,4¡¦-difluorodiphenyl phenyl phosphine oxide comonomer incorporated into the terpolymer backbone were precisely controlled from 0-50 mole percent relative to the 4,4¡¦-dihalodiphenyl sulfone. Phosphine oxide moieties were employed to enhance the interactions with the PTA relative to the pure copolymer. The composite BPSH45-PPO membranes exhibited lower HPA molecule water extraction after acidification at room and boiling temperatures, which was ascribed to the strong hydrogen and polar interactions between the phosphine oxide moiety and functional groups on the HPA. The membranes containing HPA displayed improved conductivity at high temperatures and low relative humidities when compared to the pure terpolymer samples. The increase of proton conductivity was attributed to the water retention characteristics of the HPA molecules, which allowed enhanced mobility of the protons even at lower humidification levels, providing superior hydrogen-air fuel cell performance.
The effect of hexafluoroisopropylidene bisphenol (6FBP) incorporation into 45 mole percent disulfonated poly(arylene ether sulfone) copolymers was investigated. This novel series of directly disulfonated poly(arylene ether sulfone) copolymers with various mole ratios of the 6FBP were synthesized in high molecular weight. The levels of fluorination within the statistically random copolymer architecture were varied from 0-100 mole percent using 6FBP and the correct stoichiometric amount of 4,4¡¦-biphenol. The 6FBP monomer was introduced to decrease the water swelling and improve bonding characteristics with Nafion-bonded electrodes. Indeed, water uptake decreased with increasing incorporation of the 6FBP monomer into the terpolymer. This suggested that the hydrophobic fluorinated material aided in water repulsion of the system. Proton conductivity decreased slightly as the amount of fluorination increased, which was interpreted to be due to the decrease in the ion-exchange capacity. High temperature hydrogen/air fuel cell experiments indicated better Nafion-bonded electrode adhesion for the partially fluorinated materials, as depicted by high temperature (120 ¢XC) and low humidity (50% RH) hydrogen-air fuel cell performance.
Investigations into polymeric electromechanical transducers were based on poly(arylene sulfone) ion-exchange membranes bonded between two conductive metal layer electrodes. Imposed deformations and small electric fields allowed similar explorations of both sensing and actuation applications. These copolymers produced larger sensitivities than the benchmark Nafion systems, which was interpreted as being due to their higher hydrated moduli. Methodologies for better defining the morphology of the electrodes were identified to enhance the capacitance and effective interfacial area of the conductive electrodes. The new procedures afforded major improvements to performance and transduction. Transducer actuation at lower frequencies was improved by employing a new direct assembly electrode fabrication technique that suggested a strong correlation between the capacitance and charge motion.Ph. D.
35
Goutte, Pascale. "Synthese et proprietes de polyoxirannes et polythiirannes porteurs de fonctions aldehyde potentielles." Paris 6, 1988. http://www.theses.fr/1988PA066266.
Abstract:
Synthese et polymerisation de diethoxy-1,1 epoxy-2,3 et diethoxy-1,1 epithio-2,3 propane racemiques en vue de preparer des polyethers et polythioethers ayant des fonctions aldehydes dans la chocine laterale
36
Flack, Larry A. "Nurse exposure to waste anesthetic gases in a post anesthesia care unit." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001579.
37
Dejean, de La Batie Rémi. "Etude des mouvements moléculaires dans les polymères en masse par résonance magnétique nucléaire du 13c et simulation de Monte-Carlo." Paris 6, 1986. http://www.theses.fr/1986PA066284.
Abstract:
Etude des mouvements locaux dans le polyvinylmethylether, le polybutadiene-1,4cis et le polyisoprene-1,4cis, le polyisobutène, les polyéthers en masse; polyoxypropylène et réseaux de polyoxyéthylène, influence de la microstructure sur les mouvements moléculaires locaux. Etude de la transition vitreuse dans les polymères en masse par simulation de Monte-Carlo dynamique; simulation de systemes de polymères places dans le réseau tétraédrique et simulation de systemes de sphères libres et de systemes de polymères en milieu continu.
38
Pham, Van Cang Christian. "Etude de la dynamique locale dans les polymeres en masse par l'analyse de la fluorescence de sondes excimeres." Paris 6, 1987. http://www.theses.fr/1987PA066195.
Abstract:
Les molecules de meso di(n-carbazolyl)-2,4 pentane et oxyde de bis(phenyl-10 anthryl-9 methyl) servent de sondes fluorescentes pour l'analyse de la mobilite des chaines macromoleculaires de: polyoxydes de propene, polysiloxane, polybutadiene, polyisopropene et polyisobutene. Influence de la nature du polymere sur le mouvement de la sonde
39
辜卡力. "diasetereoselective allylation of chiral glyoxylic oxime ethers and reduction of N-phenyl camphorpyrazolidinone derived a-keto amides." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/27426717406539814429.
Abstract:
博士國立臺灣師範大學
化學系
94
In the first part of this monograph, various chiral glyoxylic oximes were prepared to develop a new route to synthesize chiral α-amino amides, which are synthetic intermidiates of α-amino acids. The allylation of camphor sultam derived glyoxylic oxime ether by allyltributyltin in the presence of Lewis acids Zn(OTf)2, AgOTf, Sn(OTf)2 provided homoallylic α-amino amides, and Sn(OTf)2 emerged as the best Lewis acid when tested in allylation of various chiral glyoxylic oxime ethers. To continue the research in allylation of glyoxylic oxime ether, we studied allylation by using triallylaluminium. The reaction of triallylaluminium with chiral glyoxylic oxime ethers provided homoallylic amine products up to > 99% diastereoselectivity. In the following parts, we have investigated the scope of N-phenyl camphorpyrazolidinone in synthetic organic chemistry. When N-phenyl camphorpyrazolidinone derived α-keto amides employed in hydride reduction, the hydride reduction of aliphatic and aromatic α-keto amides provided corresponding α-hydroxy amides in excellent yields and very high level of diastereoselectivities.
40
Kursawe, Ansgar. "Partial Oxidation of Ethene to Ethylene Oxide in Microchannel Reactors: Partial Oxidation of Ethene to Ethylene Oxidein Microchannel Reactors." Doctoral thesis, 2009. https://monarch.qucosa.de/id/qucosa%3A19374.
Abstract:
In der vorliegenden Arbeit wurde die heterogen katalysierte Oxidation von Ethen zu Ethylenoxid an Silberkatalysatoren untersucht. Ziel dieser Arbeit war es, Mikrostrukturreaktoren für schnelle und stark exotherme Oxidationsreaktionen zu erproben und diese Epoxidation diente als Modellreaktion. Gleichzeitig wurden explosions- und flammhemmende Eigenschaften des Mikrostrukturreaktors ausgenutzt, um die partielle Oxidation von Ethen zu Ethyenoxid im Explosionsbereich (> 9% Sauerstoff) ohne Sicherheitsprobleme zu ermöglichen.
Um die gesteckten Ziele zu erreichen wurden zwei parallele Lösungswege beschritten. Zunächst wurden modulare Mikrostrukturreaktoren und geeignete mikrostrukturierte Katalysatorträger entwickelt, um Untersuchungen verschiedener katalytischer Beschichtungen in dieser neuen und nicht allgemein verfügbaren Reaktorbauweise zu ermöglichen. Zur katalytische Erprobungen dieser Konstruktion war es notwendig, geeignete Beschichtungstechniken zur Immobilisierung katalytisch aktiver Spezies zu entwickeln. Durch die Bauweise dieser Reaktoren als Wandreaktor erschien es anfänglich nicht möglich, kommerziell verfügbare pellet-artige Katalysatoren zu verwenden.
Daher wurden, parallel zur Konstruktion der modularen Mikroreaktoren, verschiedene auf Silber basierende Beschichtungstechniken hinsichtlich ihrer Eignung für diese Reaktion erprobt. Zur Erprobung kamen u.a. Silberimmobilisierung in einem durch anodischen Oxidation erzeugen Porensystem bzw. einer durch Sol-Gel Beschichtung erzeugten a-Aluminiumoxid Schicht und die Abscheidung von metallischem Silber per Vakuumbeschichtung auf einem Trägermaterial. Zuletzt wurde die Immobilisierung eines gemahlenen, kommerziellen Katalysators per elektrostatischer Pulverabscheidung auf einem entsprechend präparierten Trägermaterial vorgenommen und erfolgreich erprobt.
Die wichtigste Erkenntnis dieser Arbeit aus chemisch-katalytischer Sicht ist der enorm positive Einfluss hoher Sauerstoffkonzentrationen auf die Selektivität und gleichzeitig den Umsatz des umzusetzenden Ethylens. Wird die Sauerstoffkonzentration von unter 10% auf bis zu 80% erhöht, so steigt die Selektivität zu Ethylenoxid um ca. 10% an und simultan kann der Umsatzgrad abhängig vom Katalysator und der Reaktortemperatur um den Faktor 2 bis 10 gesteigert werden. Diese Beobachtung wurde für jeden funktionierenden Katalysator gemacht, unabhängig von dessen Herstellung. Mittels Promotoren wie Cs-Salzen und Stickoxiden konnte die Selektivität in Abwesenheit gängiger Moderatoren wie Chlorkomponenten auf 70% (Cs-Salze) bzw. 75% (NOx) gesteigert werden.
Verfahrenstechnisch ist festzuhalten, dass Mikrostrukturreaktoren gleich welcher Bauweise unter allen Reaktionsbedingungen thermisch stabil und beherrschbar blieben. Es wurden Umsatzgrade bis 99% bezüglich Ethen erzielt bzw. Reaktionstemperaturen von über 630 K bei einem binären Ethylen-Sauerstoff Gemisch (20%/80%) angewendet. Angesichts adiabater Temperaturerhöhungen von mehr als 3000 K konnte dennoch ein stabiler Betrieb des Reaktors festgestellt werden. Diese thermische Stabilität war bei Katalysatoren in Festbettreaktoren nicht gegeben.
41
Wang, Shao-Chien, and 王韶謙. "1.Palladium-Catalyzed ortho-C-H Bond Activation of Acetophenone Oxime Ethers2.Investigation of Blue LEDs Promoted Synthesis of Dithioacetals." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/97404562666650034342.
Abstract:
碩士國立中興大學
化學系所
105
In the first part of this thesis, we report an efficient palladium-catalyzed ortho-C-H arylation of acetophenone oxime Ethers with aryl pinacol boronic esters, leading to the biaryl derivatives in good yields. The sequential process of iridium-catalyzed C-H borylation and palladium-catalyzed ortho-C-H arylation makes the present protocol access functionalized biaryl arenes. In the second part of this thesis, we achieve a simple and elegant method for dithioacetalization of aldehyde using blue LEDs irradiation under photochemical reaction. The salient features of this method are broad substrate scope, good tolerance of electron donating and withdrawing group, and metal free and solvent free conditions. It is noteworthy that our present protocol is eco-friendly in nature and we will develop LEDs-promoted reaction in future green chemistry avenues.
42
Chia-YuKung and 孔家瑜. "Influence of Polyethylene Oxide Alkyl Ether on the Interaction between Poly(methacrylic acid) and Poly(N-vinylpyrrolidone)." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71092911012553067509.
Abstract:
碩士國立成功大學
化學工程學系碩博士班
101
Poly(N-vinylpyrrolidone) ( PVP ) form complexes with poly(methacrylic acid) ( PMA ) by hydrogen bonding. The main purpose of the study is the influence of nonionic surfactant Tergitol 15-S-9 and Tergitol 15-S-30 on the complexes of PMA and PVP. This investigation is classified according to surfactant. The first section is Tergitol 15-S-9 system, and the second section is Tergitol 15-S-30 system. The interaction between surfactant and PVP, PMA in different pH respectively, and PMA/PVP complexes in different pH were investigated by fluorescence, transmittance, pH measurements and aggregation number. In Tergitol 15-S-30 system, its EO chain length is longer than Tergitol 15-S-9, so the number of hydrogen bonding formed with PMA increases, that the influence of hydrogen bond on PMA and PMA/PVP complexes is more marked than Tergitol 15-S-9 system. Hydrogen bonding affects the solution properties obviously in acidic solution.
43
Chih-LiangHsu and 徐志良. "Thermodynamic analysis of partial oxidation of coke oven gas, iron oxide indirect reduction and dimethyl ether (DME) syntheses." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39940429348458298948.
44
ZHANG-JIAN, GUO-PING, and 張簡國平. "Synthesis､molecular micro-structure and mesomorphic behavior of terminally carboxyl oligo (ethylene oxide) monomethyl ethers-substituted side chain liquid crystalline polysiloxane and copolysiloxane polymers." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/98239961271486733827.
45
Yi-TingChen and 陳怡婷. "Influences of Hydrophilic Chain Length of Polyethylene Oxide Alkyl Ether on the Complexation between Poly(acrylic acid) and Poly(N-vinylpyrrolidone)." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/32686943508571678719.
Abstract:
碩士國立成功大學
化學工程學系碩博士班
100
The major idea of the research is the influence of noionic surfactant Tergtitol 15-S-9 and 15-S-30 on the polymer complexes of poly(N-vinylpyrrolidone) ( PVP ) and poly(acrylic acid) ( PAA ). The PVP/PAA hydrophobic complexes form due to the hydrogen bond between the pyrrolidone belong to PVP and the carboxylic acid belong to PAA. When adding surfactant to PVP/PAA system, the hydrophobic interaction between PVP and PAA decrease, because the interaction between surfactant and polymer reduce the hydrogen bonding between PVP and PAA. There are hydrophobic interaction between alkyl groups in surfactant , PVP and PAA, and hydrogen bonding interaction in a portion of PAA system with the ethylene oxide ( EO ) chains of “Tergitol 15-S-n” surfactant. The investigation divide into two sections. The first section is Tergitol 15-S-9 system, and the second section is Tergitol 15-S-30 system. The interaction between (1) PVP and surfactant (2) PAA in different pH and surfactant (3) PVP/PAA complexes in different pH and surfactant were characterized by Fluorescent, specific viscosity, pH and aggregation number in both systems. After unscramble the result of the investigation, discovering the interaction between PAA and surfactant was week in the Tergitol 15-S-9 system, and when the EO chain of surfactant become longer the interaction between surfactant and PAA or PVP/PAA complexes increase.