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1
Sumer, Burak. "Synthesis Of 1,2-amino Alcohols Having Tertiary Alcohol Moiety." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607276/index.pdf.
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An applicable method for the racemic synthesis of 1,2-amino alcohols having tertiary alcohol moiety was developed. This method can be used as a general method for the synthesis of various 1,2-amino alcohols with various tertiary alcohol moieties by changing chloroacetone with different monohalo ketones, and with different aryl halides or alkyl halides. The resultant racemic 1,2-aminoe alcohols were tried to resolve by using various hydrolase type enzymes under different conditions by changing the parameters i.e. solvent, temperature and substrate: enzyme ratios. Finally, poorly resolved amino alcohol 20 with 21 % was used as chiral ligand in diethyl zinc reaction to benzaldhyde and afforded (R)-1-phenylpropan-1-ol almost with 21 % e.e..
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Imbault, Alexander Luis. "Alcohol synthesis using metal phosphides." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53655.
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Biofuels make up to 10wt% of gasoline sold in the United States of America and Canada, the largest portion of these biofuel additives is ethanol. Past research working with MoP/SiO₂ using syn gas (H₂:CO 1:1) as a feed have shown how an effective oxygenate catalyst can be promoted with K to become more selective towards ethanol. In this thesis, various metal phosphide catalysts including CoP, Co₂P, RuP and Fe₂P (all supported on SiO₂) are investigated using molecular modelling and activity tests with syn gas to find an effective oxygenate catalyst which can be understood and ultimately converted into an effective ethanol catalyst. Molecular modelling is performed on metal phosphide catalysts to determine the CO adsorption strengths of several metal phosphide catalysts. The correlation between the adsorption energies and oxygenate formation is then examined. Fe₂P is shown to be a catalyst of interest for its ability to create sizable amounts of methanol and other oxygenates, and it has a moderate CO adsorption strength. The second focus of this thesis is on the effects of passivation on two metal phosphide catalysts, MoP/SiO₂ and Ni₂P/SiO₂. This is investigated through measuring H₂ uptake during TPR and CO uptake during CO chemisorption after different passiviiation techniques. The results of these measurements finds that Ni₂P/SiO₂ and MoP/SiO₂ react very differently after being kept out of contact with air, passivated in a low flow of O₂ or being exposed to ambient air after reduction.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Nguyen, Thi-Ngoc Dieu. "Allylsilanes in organic synthesis homoallylic alcohol synthesis and electrophilic alkylation." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60726.
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The chelating effect on regio- and stereochemical control of the homoallyl alcohol synthesis and electrophilic substitution of allylsilane was studied, using 2,2-dimethyl-1-$ {$1- ((S)-2-(2-methoxyethoxy)methyl) pyrrolidinyl$ }$-2-sila-4-pentene (S1) and 2,2-Dimethyl-1-$ {$1- ((S)-2-hydroxymethyl) pyrrolidinyl$ !$-2-sila-4-pentene (S2), with S1 synthesized from L-Prolinol.The synthesis of homoallyl alcohol was carried out by allyl transformation from S1 and S2 to a Lewis acid activated aldehyde. Chelation between the allylsilyl ligand and the Lewis acid:aldehyde complex was found to favor the cyclic syn-clinal over the acyclic anti-periplanar transition state, in the asymmetric synthesis of the alcohol 1-dodecen-4-ol (P1). The bulky, remote and weak chelating ligand resulted in only modest selectivity and average chemical yield.
Regio- and stereochemical control of the electrophilic alkylation of allylsilanes S1 were achieved due to chelating effect that favored $ alpha$-alkylation. The chiral chelating ligand also resulted in enhanced stereochemical control electrophilic alkylation. Steric effect, due to a large electrophile, and solvent effect that causes disruption of the chelated complex, decrease $ alpha$-selectivity.
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Lue, Bena-Marie. "Biosynthesis of phenolic lipid models using oleyl alcohol and triolein." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80324.
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The overall objective of this study was the optimization of a model enzymatic system in organic solvent media for the biosynthesis of selected phenolic lipid compounds. The model enzymatic system consisted of cinnamic acid and oleyl alcohol as substrates using commercial immobilized lipase (Novozym 435) from Candida antarctica. The experimental findings showed that an increase in the hydrophobicity of the solvent mixture and a decrease in the aw values of the reaction medium increased the initial enzymatic activity and bioconversion yield; the use of an iso-octane and butanone solvent mixture (85:15, v/v) and an initial aw of 0.05 resulted in an initial enzymatic activity of 192.7 nmol product/g enzyme/min and a corresponding bioconversion yield of 95.3% after a 16-day reaction period.
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Barks, Jenny Marie. "Stereoselective tetrahydrofuran synthesis." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307740.
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Zaman, Sharif Fakhruz. "An investigation of MoP catalysts for alcohol synthesis." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23165.
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Molecular simulation and experimental methods have been used to assess the catalytic behavior of MoP in the conversion of synthesis gas (CO, CO₂, H₂) to oxygenated hydrocarbons. The potential energy surface of synthesis gas conversion to methane and methanol was investigated on a Mo₆P₃ cluster model of the MoP catalyst. The potential energy surface (PES) for CH₄ formation was determined to be: COad → CHOad → CH₂Oad → CH₂OHad → CH₂.ad+H₂Oad → CH₃.ad+H₂Oad → CH₄+H₂O and for CH₃OH : COad → CHOad → CH₂Oad → CH₂OHad → CH₃OHad. The hydroxymethyl (CH₂OH) species was a common reaction intermediate for both CH₄ and CH₃OH formation and the simulation predicted selective formation of CH₄ rather than CH₃OH from syngas over MoP. The cluster model was modified to investigate the effect of a SiO₂ support and a K promoter. Both SiO₂ and K decreased the activation energy for methanol formation. However, the activation energy for methanol formation remained higher than the activation energy for C-O bond cleavage. The high adsorption energy of methanol and the formation of geminal dicarbonyl species on the K-Mo₆P₃-Si₃O₉ cluster suggested the possibility of the formation of higher oxygenates. The conversion of syngas to alcohols was also investigated on 5, 10, and 15 wt% MoP supported on silica, with 0, 1, and 5 wt% K added as a promoter The major products were acetaldehyde, acetone and ethanol. Low selectivities to methanol (<5 C atom %) and methane (< 10 C atom%) were observed on the 5%K-10%MoP-SiO₂ catalyst. The product distribution obtained over the K-MoP/SiO₂ catalyst was distinct from that reported in the literature over other Mo-based catalysts. Addition of Rh to the K-MoP/SiO₂ catalyst improved the stability of the catalyst. However, the Rh increased the selectivity to hydrocarbon products, especially CH4, while only increasing the selectivity to ethanol marginally. The reaction kinetics of the major products were described by a simple empirical power law. The activation energies of ethanol and acetaldehyde were very similar, suggesting that both originated from the same surface intermediate.
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Loveridge, Tracey. "Chiral chromium complexes in synthesis." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296868.
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Safinski, Tomasz School of Chemical Engineering & Industrial Chemistry UNSW. "Catalytic distillation for the synthesis of tertiary butyl alcohol." Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry, 2005. http://handle.unsw.edu.au/1959.4/23068.
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Catalytic Distillation for the synthesis of tertiary butyl alcohol (TBA) is investigated in this thesis. The solvent, ethylene glycol, is proposed as a means of overcoming challenges, which limit the potential benefits of the application of reactive separation for TBA. The proposed action of the solvent is that of extractive distillation entrainer, thus a new unit operation of Catalytic Extractive Distillation (CED) is suggested. The solubility of isobutylene in water, TBA, and ethylene glycol and their binary and ternary mixtures, at different temperatures, is measured and correlated. The solubility is found to be highly non-linear in solutions containing TBA. The kinetics of isobutylene hydration over Amberlyst 15 is characterised in the presence of ethylene glycol. The solvent is found to promote reaction rate, however it is also found to compete for reaction with isobutylene. Water is found to strongly inhibit the reaction of ethylene glycol and isobutylene. The selectivity ratio of TBA to by products is determined and found to improve with increased temperature and lower solvent concentration. Bale packing is chosen as catalytic distillation hardware for the containment of Amberlyst 15 and its two-phase fluid dynamics characterised for the first time. Raschig rings are used as a benchmark for the study. Bale packing is found to exhibit two ranges of backmixing behaviour in the pre-loading regime. This behaviour is attributed to the three levels of porosity of the hardware and indicative of low rates of catalyst/liquid renewal. The effectiveness of ethylene glycol as extractive distillation entrainer for the separation of the TBA/water azeotrope over Bale packing is investigated and the solvent found to be highly effective. The mass transfer resistances to isobutylene transport are determined for countercurrent fixed bed reactor (CFBR) application of Bale packing. It is found that ethylene glycol improves mass transfer coefficients attainable. Catalytic Extractive Distillation is implemented over Bale packing and the ability of the solvent to improve reaction rates and purity of TBA demonstrated. However, the reaction rates achieved have much scope for improvement through increased isobutylene availability. In response to poor liquid renewal of static packing such as Bale packing and the necessity of improved isobutylene transport a new form of catalytic distillation reactor design is proposed, the Basket Impeller Column (BIC). The BIC combines the mass transfer benefits of a rotating basket reactor with that of a dual flow column. Capacity of the new hardware is determined and correlated. Separation and reactive separation are demonstrated to be feasible. It is found that Damk??hler number can be varied directly using the additional process variable of speed of rotation.
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McLaughlin, M. G. "Highly selective hydrometallations and their application in synthesis." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.679265.
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Bayir, N. "Modelling of integrated de-novo pathways for amino alcohol synthesis." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1561249/.
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Chiral amino alcohols are industrially valuable intermediates used in the synthesis of many pharmaceuticals and fine chemicals. Transamination (TAm) is not only one of the most interesting industrial enzymatic reactions on its own nowadays but also the second enzymatic step of the de novo pathway studied by our research group (Bioconversion-Chemistry and Engineering Interface Programme-BiCE) for the synthesis of chiral amino alcohols. In this thesis, firstly a study on the kinetic modelling of TAm reactions was presented. Kinetic behaviour of two ω-TAm reactions employing different amino acceptors but the same amino donor was investigated. Using a Genetic Algorithm, kinetic models could be determined with only 10-12 progress curves for both reaction schemes without having any experimental data for the reverse reaction. Also, a sensitivity analysis on the kinetic parameters of both reactions was carried out. Having gained enough insight into the kinetic modelling of TAm reactions, two different sequential enzyme reactions leading to the synthesis of 2-amino-1,3,4- butanetriol (ABT) were studied. The first one involved three different enzymes, namely TAm (pQR977), Transketolase (TK) and TAm (pQR801). 100% conversion was proven possible with both experimental and simulation results in a 28 hour-long fed-batch reaction. Although, the concentrations tested in the experiments were low, this three-step sequential enzyme reaction showed great promise for further being optimized for industrial applications. The second one was a recycling sequential enzyme reaction involving three different enzymatic reactions taking place simultaneously. Two of the reactions were catalyzed by TAm (pQR1021) and one of them was catalyzed by TK. With the help of second TAm reaction not only desired product was synthesized but also one of the intermediary precursors was recycled within the system. The long term goal of this project was the integration of de novo pathways leading to the synthesis of chiral amino alcohols into host cell metabolism. Thus, the recycling sequential enzyme reaction employing only two different enzymes and two different substrates was found promising for achieving this goal. With both experimental and simulation results the favorability of this reaction was demonstrated and low amounts of ABT (~6 mM) was synthesized in a 8-hour long reaction using purified enzymes. One of the precursors in both sequential enzyme reactions was serine. In the final results chapter, a metabolic modelling methodology was used for identifying optimal metabolic engineering strategies, namely enzyme knock-outs and enzyme expression level modulations, for the overproduction of serine by employing a partial mechanistic model of central carbon metabolism of Escherichia coli. Simulation results showed 89% increase in serine synthesis in the case of doubling the expression level of SerSynth, a hypothetical enzyme for the synthesis of serine from 3-phosphoglycerate.
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Lang, Kangmin. "Synthesis and properties of thin-film polyvinyl alcohol composite membranes." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6481.
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Thin-film composite (TFC) membranes were developed with a polysulfone UF membrane used as the microporous substrate, polyvinyl alcohol as the material for skin layer formation and malic acid as the cross-linking agent. The cross-linking reactions of the membrane skin layer were carried out at high or ambient temperatures, and at the interface by using two miscible or immiscible solvents. Various parameters involved in the TFC membrane-making process have been investigated, and the flux change corresponding to individual steps in the membrane-making process was identified. The membrane transport properties and surface characteristics were studied by exposing membranes to chlorine test, by determining separations for various inorganic electrolyte and organic solutes, and by measuring ion-exchange-capacity. Separation experiments revealed the negatively charged feature of the PVA TFC membrane surface. Further, liquid chromatography was introduced to study the interfacial interaction forces working between membrane and solute in the membrane system. The TFC PVA membranes developed in this work can be classified into reverse osmosis membranes and nanofiltration membranes. The former class of membranes exhibits sodium chloride separation of 90% and product rate of 14 g/10 cm$\sp2$.h when the feed sodium chloride concentration and operating pressure are 2000 ppm and 1724 kPag, while the latter class of membranes exhibits sodium chloride separation of 70% and product rate of 45 g/10 cm$\sp2$.h at the operating pressure of 1550 kPag.
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Zhao, Yanjun. "On the investigation of alcohol synthesis via the Fischer Tropsch reaction." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/55862/.
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The Fischer Tropsch (FT) reaction is hydrogenation of carbon oxides (mainly carbon monoxide) to produce hydrocarbons and alcohols. The produced alcohols can be used as substitutes to motor fuel or as fuel additives to enhance the octane number. The use of alcohols significantly reduces the environment related pollution. This thesis was aimed to investigate the alcohol synthesis via the FT reaction. Cobalt molybdenum based catalyst and cobalt copper based mixed oxide catalyst are two patented catalyst systems for alcohol synthesis. This study investigated the preparation and evaluation of these two catalyst systems. The highest activity (30% CO conversion) and alcohol yield (methanol: 8% higher alcohols: 13%) was obtained with an operation condition of 580 K, 75 bar, GHSV = 1225 h-1 and syngas ratio of 2 for cobalt molybdenum based catalyst. Carbon monoxide hydrogenation to synthesize alcohol was also investigated over gold containing catalyst. When ZnO was used as a support, it was found that the addition of gold could shift the alcohol distribution towards higher alcohol side. The carbon monoxide and hydrogen used for the FT reaction is mainly generated by steam reforming reaction. This thesis investigated the possibility of combining the steam reforming reaction and the FT reaction together. Ruthenium supported catalysts were investigated for this purpose. The obtained results demonstrate that both steam reforming and the FT alcohol synthesis can be performed over the same catalyst in the same reactor.
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Koch, David. "Syngas, mixed alcohol and diesel synthesis from forest residues via gasification - an economic analysis." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28131.
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Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Realff, Matthew; Committee Member: DeMartini, Nikolai; Committee Member: Muzzy, John; Committee Member: Sievers, Carsten.
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Chirowodza, Helen. "Synthesis and characterization of cationically and anionically modified poly(vinyl alcohol) microfibrils." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2184.
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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009.In papermaking, the addition of filler can be detrimental to the properties of the resulting paper hence the use of additives that enhance paper properties are of paramount importance. Syndiotacticity rich poly(vinyl alcohol) (PVA) microfibrils were prepared for use as filler retention aids. They were prepared via in situ fibrillation during the saponification of high molecular weight poly(vinyl pivalate). The resulting fibers had high thermal stability and crystalline melting temperature. They were not fully soluble in water even at 100 oC. In order to make them less water resistant the syndiotacticity of the PVA microfibrils was varied by copolymerizing vinyl pivalate with vinyl acetate and saponifying the resultant copolymer. It was observed that changes in syndiotacticity had a significant effect on the crystallinity, morphology and thermal properties of the resultant PVA. The surfaces of the fibers were modified by first crosslinking using glyoxal (a dialdehyde), and then attaching cationic and anionic groups by grafting and by carboxymethylation. Crosslinking prior to modification was beneficial in minimizing the solubility of the fibers in the aqueous media in which they were modified. Heterogeneous modification techniques were employed so that fiber properties could be preserved. Carboxymethylation was carried out using the two step Williamson’s ether synthesis. The first step involves the formation of a highly reactive alkoxide by the reaction of PVA with a strong base and the second its etherification using a functional alkyl halide. Poly(methacryloyloxy ethyl trimethyl ammonium chloride) and poly(acrylic acid) were grafted from the PVA microfibrils using the KPS/Na2S2O3 redox initiation system. Grafting was confirmed by FTIR and NMR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out on both modified and unmodified PVA microfibrils. The results showed that crosslinking resulted in an enhancement of the thermal properties of the microfibrils. A decline in the onset temperature for thermal degradation and crystalline melting temperature were observed, and were attributed to the modification of the PVA microfibrils.
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Villegas, Torres M. F. "Design and characterization of novel biocatalytic cascades for chiral amino alcohol synthesis." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1425692/.
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Chiral amino alcohols are building blocks of several pharmaceuticals such as antibiotics, and retrovirals. De novo biocatalytic strategies have been developed for their production as chemical synthesis presents several challenges in establishing chiral centres. One of the successful approaches previously implemented in the Biochemical Engineering Department is the coupling of a transketolase with a transaminase step. This scheme depends on the use of hydroxypyruvate (HPA) and methylbenzylamine (MBA), which are expensive non-natural substrates limiting both the application of the pathway on an industrial scale, and its integration with the host metabolism. Therefore, this thesis examines the ability of two novel biocatalytic cascades to synthesize chiral amino alcohols from natural cheaper compounds, and the issues faced when attempting to integrate the pathways with Escherichia coli metabolism. Two different biocatalytic strategies were studied: a recycling cascade and a sequential pathway. The former, directly aminates erythrulose using serine as amino donor for the simultaneous synthesis of 2-amino-1,3,4-butanetriol (ABT) and HPA. The latter, involves three enzymatic steps carried out by two transaminases and one transketolase using serine, pyruvate and glycolaldehyde (GA) as substrates. Both coupled reactions depend on a transaminase able to use serine as amino donor. As a result, this work initiates with screening studies to identify the ideal candidates from a library of 100 transaminases. The selected enzymes were then characterized based on their main kinetic constants, KM and kcat, and their amino acceptors profiles when using serine as amino donor. From the results, two transaminases were selected for the proof of concept of the cascade reactions in a purified system. Due to the low bioconversions achieved, the work progressed towards their optimization implementing Response Surface Methodology (RSM) using a Central Composite Design (CCD). Finally, the optimized cascades were then evaluated in a whole cell environment using E. coli resting cells, exposing the challenges to be faced during their future metabolic integration. This study finalizes with a first attempt to design and build a more suitable expression system required for future work. Within this work, three new transaminases were described and characterized: two ω-transaminases isolated from Rhodobacter sphaeroides with broad amino acceptors profile using serine as amino donor; and a serine: pyruvate transaminase isolated from Deinococcus geothermalis with high substrates specificity. Both cascades were successfully tested, where the recycling system gave 30-times higher yields (30% conversion), and was more advantageous for the integration in comparison to the three-step sequential pathway. After the optimization, the yields of the recycling cascade and the sequential pathway were 2-fold and 3-fold improved, respectively. Finally based on the preliminary whole cell study of the recycling cascade and the first two steps of the sequential pathway, it became clear that the main challenges for the future metabolic integration are HPA consumption by the host, and the differential effect of the expression of different recombinant enzymes on the E. coli host cells.
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Torssell, Staffan. "Stereoselective Synthesis of Amino Alcohols : Applications to Natural Product Synthesis." Doctoral thesis, Stockholm : Kemi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4472.
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Koh, Ming Joo. "Stereoselective Synthesis of High-Value Alkenes through Catalytic Olefin Metathesis." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107636.
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Thesis advisor: Amir H. HoveydaChapter 1. Development of Ru-Based Catechothiolate Complexes for Z-selective Ring-Opening/Cross-Metathesis and Cross-Metathesis. We have developed a broadly applicable Ru-catalyzed protocol for Z-selective ring-opening/cross-metathesis (ROCM). Transformations are promoted by 2.0–5.0 mol % of a Ru-based catechothiolate complex, furnishing products in up to 97 % yield and >98:2 Z:E ratio. The Z-selective ROCM processes are found to be compatible with terminal alkenes of different sizes that include the first examples involving heteroaryl olefins, 1,3-dienes, and O- and S-substituted alkenes as well as allylic and homoallylic alcohols. Reactions with an enantioenriched α-substituted allylic alcohol are shown to afford congested Z-olefins with high diastereoselectivity. The insights gained from these investigations provided the impetus to develop electronically modified Ru catechothiolate catalysts that are readily accessible from a commercially available dichloro-Ru carbene and an easily generated air-stable zinc catechothiolate. The new complex is effective in catalyzing Z-selective cross-metathesis (CM) of terminal alkenes and inexpensive Z-2-butene-1,4-diol to directly generate linear Z-allylic alcohols, including those that bear a hindered neighboring substituent or reactive functionalities such as a phenol, an aldehyde or a carboxylic acid. Transformations typically proceed with 5.0 mol % of the catalyst within 4–8 hours under ambient conditions, and products are obtained in up to 80% yield and 98:2 Z:E selectivity. Utility is highlighted through synthesis of a molecular fragment en route to anti-tumor agent neopeltolide and in a single-step stereoselective gram-scale conversion of renewable feedstock to synthetically valuable Z-allylic alcohols. Chapter 2. Kinetically Controlled Z- and E-Selective Cross-Metathesis to Access 1,2- Disubstituted Alkenyl Halides. We have discovered that previously unknown halo-substituted molybdenum alkylidenes are capable of participating in highly efficient olefin metathesis reactions that afford linear 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by 1.0–10.0 mol % of a Mo-based pentafluorophenylimido monoaryloxide pyrrolide (MAP) complex that is generated in situ and used with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents, delivering a myriad of alkenyl chlorides, bromides and fluorides in up to 91% yield and >98:2 Z:E ratio. Through mechanism-based modification of the aryloxide ligand, a newly synthesized Mo-based MAP complex was shown to be effective in promoting kinetically controlled E-selective CM to access the corresponding thermodynamically less favored E-isomers of alkenyl chlorides and fluorides. Reactions typically proceed within 4 hours at ambient temperature with 1.0–5.0 mol % of the catalyst, which may be utilized in the form of air- and moisture-stable paraffin pellets. Utility of the aforementioned protocols is demonstrated through preparation of biologically active compounds and related analogues as well as late-stage site- and stereoselective fluorination of complex organic molecules. Chapter 3. Molybdenum-Based Chloride Catalysts for Z-Selective Olefin Metathesis. A new class of Mo-based monoaryloxide chloride (MAC) complexes for Z-selective olefin metathesis has been developed. The MAC catalysts are capable of promoting CM with commercially available, inexpensive and typically inert Z-1,1,1,4,4,4-hexafluoro-2-butene to furnish the higher-energy Z-isomers of trifluoromethyl-substituted alkenes in up to 95% yield and >98:2 Z:E selectivity. Furthermore, otherwise inefficient and non-stereoselective transformations with Z-1,2-dichloroethene and 1,2-dibromoethene can be accomplished with appreciably improved efficiency and Z-selectivity. The method enables synthesis of biologically active compounds and CF3-analogues of medicinally relevant molecules. Density functional theory (DFT) calculations shed light on the origins of the activity and selectivity levels observed in these transformations. Chapter 4. Stereoselective Synthesis of Z- and E-Trisubstituted Alkenes by Merging Cross-Coupling with Cross-Metathesis. We have discovered that challenging acyclic E- and Z-trisubstituted alkenes, particularly alkenyl chlorides and bromides, can be accessed efficiently and in high stereoisomeric purity (up to >98% E and 95% Z) through a sequence involving catalytic cross-coupling followed by stereoretentive CM promoted by Mo-based catalysts. Initial exploratory studies with 1,1-disubstiuted alkenes revealed crucial mechanistic features of the transformations that led us to utilize readily accessible trisubstituted olefins as substrates, in combination with commercially available 1,2-dihaloethenes as cross-partners for CM. Applications to synthesis of biologically active compounds and synthetic precursors underscore utility. The stereoretentive transformations may be extended to trisubstituted non-halogenated alkenes such as aliphatic olefins
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Andrews, Benjamin I. "The asymmetric desymmetrisation of meso compounds." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340147.
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Li, Liwei. "Density functional theory study of alcohol synthesis reactions on alkali-promoted Mo2C catalysts." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53456.
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As an important chemical raw material, alcohols can be used as fuels, solvents and chemical feedstocks to produce a variety of downstream products. With limited fossil fuel resources, alcohol synthesis from syngas reactions can be a potential alternative to the traditional petroleum based alcohol synthesis. Among many catalysts active for syngas to alcohol processes, alkali promoted Mo2C has shown promising performance. More interestingly, the alkali promoter was found to play an important role in shifting the reaction selectivity from hydrocarbons to alcohols. However, limited understanding of the mechanism of this alkali promoter effect is available due to the complexity of syngas reaction mechanism and low content of alkali added to the catalysts. In this thesis, we performed a comprehensive investigation of the alkali promoter effect with density functional theory (DFT) calculations as our primary tool. We first examine various Mo2C surfaces to determine a representative surface structure active to alkali adsorption. On this particular surface, we develop a syngas reaction network including relevant reaction mechanisms proposed in previous literature. With energetics derived from DFT calculations and a BEP relation, we predict the syngas reaction selectivity and find it to be in excellent agreement with experimental results. The dominant reaction mechanism and selectivity determining steps are determined from sensitivity analysis. We also propose a formation mechanism of alkali promoters on Mo2C catalysts that shows consistency between experimental IR and DFT computed vibrational frequencies. Finally, the effect of alkali promoters on the selectivity determining steps for syngas reactions are investigated from DFT calculations and charge analysis. We are able to rationalize the role of alkali promoters in shifting the reaction selectivity from hydrocarbons to alcohols on Mo2C catalysts.
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Adjei, Bernard Louis. "The Synthesis and Characterization of Diastereomeric Phosphorus Mustards Derived from Chiral Amino Alcohol." Youngstown State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1566419465752266.
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Kleissler, Charles Richard. "Comparison of poly(vinyl alcohol) backbone-grafted ethers and chain-growth crown ether polymers in selective cation adsorption." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/10115.
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Ly, Tai Wei. "Synthetic studies on terpenoids, total synthesis of the marine natural product nanaimoal : towards the total synthesis of solidago alcohol via an intermolecular Diels-Alder approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0011/NQ59991.pdf.
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Sunbul, Murat. "Asymmetric Synthesis Of Norbornene Based 1,4-amino Alcohol Derivatives And Applications In Asymmetric Transformations." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606174/index.pdf.
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The asymmetric synthesis of cis-1,4-aminoalcohols with norbornene backbone was performed starting with simple and cheap anhydride 30. Quinine-mediated desymmetrization of anhydride 30 with methanol resulted in (2S,3R)-(-)-cis-hemiester 31 (98% e.e.). Chemoselective amination with HMPTA and NH4OH followed by LAH reduction afforded (2S,3R)-(+)-36 and (2S,3R)-(-)-37, respectively. The amidoester (2S,3R)-(-)-32 was transformed into chiral ligand (2S,3R)-(-)-35 with Grignard reaction followed by LAH reduction.
The chiral ligands (2S,3R)-(-)-35, (2S,3R)-(+)-36 and (2S,3R)-(-)-37 were subjected to asymmetric diethylzinc addition reaction to examine their effectiveness as chiral catalyst. Among these, chiral ligand 36 exhibited the highest enantioselectivity (88% e.e.)
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Miyata, Yasumitsu, Keiichi Kamon, Kazunori Ohashi, Ryo Kitaura, Masamichi Yoshimura, and Hisanori Shinohara. "A simple alcohol-chemical vapor deposition synthesis of single-layer graphenes using flash cooling." American Institute of Physics, 2010. http://hdl.handle.net/2237/14182.
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Morrill, Michael R. "Higher alcohol synthesis on magnesium/aluminum mixed oxide supported potassium carbonate promoted molybdenum sulfide." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52190.
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Higher alcohols synthesized via CO hydrogenation reactions have been a topic of intense study both in industry and academia for over thirty years. A variety of transition metals and promoters have been used in catalysts for this reaction. MoS₂, in particular, is popular due to its low cost, resistance to sulfur poisoning, and ability to selectively produce higher alcohols over hydrocarbons.
The bulk material has a rich history in hydrodesulfurization reactions (HDS), and as such, a great deal is known about the material's structure and reactivity. However, even with this deep body of knowledge about the bulk catalyst, no one has yet been able to implement an industrially viable variation of the catalyst to make higher alcohols.
Supported MoS₂ has also been studied for the same purpose. Generally, supports are employed to improve catalyst productivity per gram of Mo by dispersing the metal and increasing the amount of catalytically active surface area. However, product selectivity may also be influenced by chemical properties of the supports. Specifically, gamma alumina has been shown to raise hydrocarbon formation due to intrinsic surface acidity.
The effects of basic supports are reported on the CO hydrogenation reaction are reported. K promoted Mo is supported on two basic materials - commercial sepiolite (Si₁₂Mg₈O₃₀(OH)₄) and hydrotalcite-derived Mg/Al mixed metal oxides (MMO). The catalysts are reacted with syngas, and the resultant product selectivities are compared at isoconversions. Activated carbon supported Mo and bulk MoS₂ are also used as controls. It is shown that MMO provides a unique promotional effect by suppressing methanol formation and favoring higher alcohols.
The specific role of MMO in the reaction is investigated by combining it in three different ways with Mo. 1) MMO is impregnated with Mo in the classic fashion. 2) Bare MMO or MMO/K is placed as a secondary bed downstream of the principle catalyst (K promoted Mo supported on MMO). 3) Bare MMO or MMO/K is mixed with the principle catalyst to make a homogeneous bed.
It is shown that MMO by itself is somewhat inert in the reaction while MMO/K has some higher alcohol forming activity. More importantly however, it is shown that the MMO:Mo ratio has far greater effects on selectivity than the morphology of MoS₂. There is evidence however that MoS₂ morphology can affect activity. It is hypothesized that a greater degree of stacking in MoS₂ domains leads to reduced activity.
The existence of coupling and homologation pathways are investigated by feeding methanol or ethanol into the syngas as it enters the catalyst bed. By comparing changes in the productivity of different higher alcohols with the liquid feed, it is shown that an MMO supported catalyst is much more reactive with methanol and somewhat more reactive with ethanol than its bulk MoS₂ counterpart. It is shown that for both the bulk and supported catalysts, the addition of a Cx alcohol results in the largest increase in Cx+1 products, suggesting that alcohol homologation is in fact the most favored route to higher alcohols by these materials.
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O'Malley, P. J. R. "Adsorption and reaction on promoted zinc oxide catalysts in relation to higher alcohol synthesis." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/47515.
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King, Peter Andrew. "Synthesis and characterisation of poly(vinyl alcohol) based materials for use within personal products." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/11355/.
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Cationic polymers based upon poly(vinyl alcohol) (PVA) are synthesised with various levels of charge densities, molecular architectures and hydrophobicities. Furthermore, macroinitiators incorporating PVA segments are synthesized and subsequently used for single electron transfer - living radical polymerisation (SET-LRP) for the synthesis of a range of graft copolymers. Chapter 1 is a general introduction on cationic polymers, their use within conditioning shampoo formulations and the chemical properties required for this application. The polymerisation techniques: ring-opening polymerisation and reversible deactivation radical polymerisation (RDRP); as well as the polymeric materials: PVA and polyglycerol are also discussed. Chapter 2 involves the synthesis of cationic PVA through either etherification or esterification reactions. The etherification of PVA using either glycidyltrimethylammonium chloride (GTMAC) or 1,2-chlorohydroxypropyltrimethyammonium chloride (CHPTMAC) to synthesise poly[(vinyl alcohol)-ran-(vinyl, 2-hydroxypropyl ether trimethylammonium chloride)] (P[VA)-r-(VETMAC)]) is investigated. The charge densities of the polymers synthesised by slowing the rate of reaction with GTMAC were determined to be greater than the charge densities claimed in the literature. The synthesis of poly(vinyl betaine) (PVB) via the synthesis of poly(vinyl chloroacetate) as an intermediate is discussed, as well as attempts to control the charge density of the resulting PVB. The charge density of the synthesised polymers were determined using UV-Vis spectroscopy and by nuclear magnetic resonance (NMR) spectroscopy. Chapter 3 discusses the synthesis of a novel hyperbranched graft copolymer, poly[(vinyl alcohol)-graft-(hyperbranched glycerol)] (P[(VA)-g-(hPG)]). The effects of the reaction conditions on the mole fraction of hyperbranched polyglycerol (x(hPG)), the degree of branching (%DB) and the degree of substitution (%DS) were all monitored for the water solvated reactions. The synthesis of P[(VA)-g-(hPG)] in organic solvents is also discussed. Furthermore, comparisons between P[(VA)-g-(hPG)] and physical blends of PVA and hyperbranched polyglycerol are also made. Chapter 4 entails the synthesis of cationic polymers based upon P[(VA)-g-(hPG)] synthesised in Chapter 3. Poly[(vinyl alcohol)-ran-(vinyl,2-hydroxypropyl ether trimethylammonium chloride)-graft-(hyperbranched polyglycerol-2-hydroxypropyl ether trimethylammonium chloride)] (P[(VA)-r-(VETMAC)-g-(hPG-PETMAC)]) was synthesized from the reaction between P[(VA)-g-(hPG)] as the macroinitiator and GTMAC. The charge density of the resulting polymer was found to increase with increasing x(hPG) in themacroinitiator; charge densities up to 5.4 meq g-1 were determined. Furthermore, the synthesis of poly[(vinyl betaine)-graft-(hyperbranched polyglycerol betaine)] is also discussed. Chapter 5 describes the synthesis of hydrophobic derivatives of the polymers synthesized in the previous chapters using epoxyoctane to synthesise poly[(vinyl alcohol)-ran-(vinyl, 2- hydroxy octyl ether)], poly[(vinyl alcohol)-ran-(vinyl, 2-hydroxy octyl ether)-ran-(vinyl, 2- hydroxypropyl ether trimethylammonium chloride)], poly[(vinyl alcohol)-ran-(vinyl, 2- hydroxy octyl ether)-graft-(hyperbranched polyglycerol-2-hydroxyoctyl ether)] and poly[(vinyl, 2-hydroxy octyl ether)-ran-(vinyl, 2-hydroxypropyl ether trimethylammonium chloride)-ran-(vinyl alcohol)-graft-(hyperbranched polyglycerol)-(2-hydroxypropyl ether trimethylammonium chloride)/(2-hydroxy octyl ether)]). The hydrophobicity of the synthesised polymers is measured based upon their contact angle and aqueous solubility. Chapter 6 focuses on the synthesis of macroinitiators for RDRP containing PVA and poly(vinyl, 2-bromopropionate) (PVBrP) repeat units. 2-bromopropionic anhydride was synthesised for the reaction with PVA. Poly[(vinyl, 2-bromopropionate)-ran-(vinyl2- butyral)] was synthesised when the reaction was carried out in butanone. However when 1,4-dioxane was used as the reaction solvent poly[(vinyl alcohol)-ran-(vinyl, 2- bromopropionate)] (P[(VA)-r-(VBrP)]) was successfully synthesised, with 62% or 79% initiating groups (PVBrP groups). Chapter 7 details the synthesis of graft copolymers by SET-LRP, using P[(VA)-r-(VBrP)] macroinitiators which were synthesised in Chapter 6. Methyl acrylate was polymerised with P[(VA)-r-(VBrP)] macroinitiators containing 62% or 79% initiating sites (PVBrP), with a molecular weight of 2.31 x 106 gmol-1 determined by atomic force microscopy. Hydroxyethyl acrylate was polymerised with P[(VA)-r-(VBrP)] macroinitiator containing 62% initiating sites to synthesise poly[(vinyl alcohol)-ran-(vinyl 2-bromopropionate)-graft- (hydroxyethyl acrylate)] (P[(VA)-r-(VBrP)-g-(HEA)]), a water soluble polymer. When unpurified HEA monomer was polymerised, a cross-linked material was recovered with a 50% swelling ratio. N-isopropylacrylamide was also polymerised using P[(VA)-r-(VBrP)] macroinitiator containing 62% initiating sites, to synthesise a thermoresponsive polymer with a lower critical saturation temperature of 36 oC. Chapter 8 surmises and concludes the work covered in Chapters 2 - 7, and further work is also suggested.
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Boogaerts, Ine Ida Françoise. "Novel catalysts for the hydroxymethylation of allyl alcohol : a convenient synthetic route to 1, 4-butanediol." Thesis, University of St Andrews, 2009. http://hdl.handle.net/10023/959.
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Hydroxymethylation catalysis provides a valuable strategy for the high volume production of alcohols from α-alkenes. Generally this involves a hydroformylation-hydrogenation sequence, but the capacity to optimise selectivity for each transformation is limited. Condensation reactions between aldehyde products and alcohol products frustrate process economics. By an alternative scheme, all relevant bond-forming reactions occur in a single mechanism. This thesis describes several approaches to catalyst development and the application of derived systems for the hydroxymethylation of allyl alcohol. A review of auto-tandem hydroxymethylation and domino hydroxymethylation is presented in Chapter 1. In Chapter 2 the synthesis of bis-(diethylphosphine) ligands based on a modular series of chiral alicyclic scaffolds is described. High pressure NMR studies have shown that the catalytically active complex [RhH(CO)₂(L-L)] adopts preferentially ea geometry, with [Rh(CO)(L-L)(μ-CO)]₂ as the primary competing species. Catalyst performance can be correlated with the flexibility of the chelating ring; this favoured a high monomer/dimer ratio which enhances activity, but could not rigidify the configuration of the diethylphosphine groups which inhibits linear selectivity. Deuterium labelling studies were suggestive of a domino hydroxymethylation scheme. From the rhodium-hydroxyalkyl-hydride-carbonyl cation, a reductive elimination furnishes the diol derivatives and a β-hydride abstraction furnishes the hydroxyaldehyde derivatives. Up to 53 mol% selectivity to 1, 4-butanediol was attained. The catalysts could be recycled via biphasic separation, however poisoning by methacrolein caused a decline of activity upon reuse of the solution. An investigation of enhanced specific activity via the meta-effect is the subject of Chapter 3. The effect of systematic meta-substitution in triphenylphosphine upon physicochemical properties was investigated by IR spectroscopy and electrochemistry, both of which showed no significant structural impact on the uncoordinated triarylphosphine. Variable temperature ¹H NMR studies however revealed a change in the solution dynamics of the corresponding Vaska complex. The activation barrier to phosphorus-(ipso)carbon rotation increases as a function of meta-substitution, with rotation of substituted aryl rings past each other being more strained. This should create a well-defined coordination sphere around rhodium, and is proposed to account for the high linear selectivity observed in the hydroformylation of allylic alcohols with [RhH(CO){(3, 5-Me₂Ph)P}₃]. Linear-selectivity reached 96 mol%. Catalyst recycling was executed via biphasic separation, retaining on over twelve cycles an average of ~ 94 % efficiency. The kinetics of allyl alcohol hydroformylation with [RhH(CO){(3, 5-Me₂Ph)P}₃] was found to be well represented by Equation 11 (Section 3.6) A detailed analysis of how substrate-specific the influence of the meta-effect remains to be performed. In Chapter 4 domino hydroxymethylation by multi-component L-L/PEt3/Rh systems is described. The regioselective performance of a diphosphine rhodium catalyst in hydroformylation was translated for hydroxymethylation upon introduction of triethylphosphine at a L-L/PEt3 molar ratio ≥ 1. The highest observed selectivity to 1, 4-butanediol was 66 mol%. Competitive activity of triethylphosphine-modified rhodium species presumably accounts for the reduced linear selectivity observed when L-L/PEt3 molar ratio < 1. Despite aggravated catalyst decomposition at higher triethylphosphine concentrations, heterogeneous hydrogenation does not appear to take place. Deuterium labelling studies also discount a sequential homogeneous hydrogenation. There is evidence for the activation of a tris-phosphine-modified rhodium-acyl-carbonyl complex, but such a species could not be isolated from complexation reactions with a variety of precursors. It would be of interest to determine alternative promotors and to establish whether it is preferential to employ a high concentration of mildly acidic species or a low concentration of highly acidic species. The self-assembly of DNA base pair analogues 2-N-pivaloylaminopyridyl phosphine and isoquinolyl phosphine, each modified with diphenylphosphine, diethylphosphine, dicyclohexylphosphine and bis(3, 5-dimethylphenyl)phosphine, is described in Chapter 5. In the presence of a rhodium precursor, exclusive formation of the heteroleptic complex was observed. Although the intramolecular hydrogen-bonding network is sensitive to temperature and free hydroxyl functionalities, highly regioselective catalysts were generally afforded under the appropriate operating conditions. Only the catalyst based on the bis(dicyclohexylphosphine)-heterodimer performed poorly, presumably due to the formation of mono-phosphine complexes. High chemoselectivity was correlated with the heterodimer acidity constant, however this is rendered non-linear by a trans influence when electronic distinction between the platforms is high. Overall, complexes based on the assembly of a dicyclohexylphosphine platform and a bis(3, 5-dimethylphenyl)phosphine platform were found to be optimal; up to 73 mol% selectivity to 1, 4-butanediol was reached. It has been demonstrated in this thesis that in order to effect linear-selective domino hydroxymethylation of allyl alcohol, two distinct transition state structures must be optimised. High regioselectivity demands an asymmetric rhodium-hydride-dicarbonyl complex, which can be generated by an asymmetric chelate or by rigidifying the configuration of the substituents on phosphorus. Interestingly, chelation geometry in this transition state has little impact on this parameter. It has been shown that domino hydroxymethylation is activated by an electron-rich rhodium-acyl-dicarbonyl. The state of electron density on rhodium can be controlled by the substitution pattern on the phosphorus donors, but can also be changed by the inclusion of a suitable promoter. The chelation geometry in this transition state is more significant; placing the acyl functionality trans to a phosphorus donor concentrates the electronic effect in the rhodium-alkyldiol-hydride-carbonyl cation to such an extent as to impede hydride migration and reductive elimination of the diol, favouring β-hydride abstraction and reductive elimination of the hydroxyaldehyde.
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Levitt, Danielle E. "Resistance Exercise and Alcohol: Combined Effects on Physiology and Performance." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1248374/.
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Resistance exercise (RE) training is a well-known and effective method for promoting increases in muscle mass and strength. A single bout of RE induces physiological disturbances that require coordinated activation of the immune system and intramuscular signaling in order to return the tissue to homeostasis and adapt to the RE challenge. On the other hand, acute binge alcohol consumption can affect the immune response to an inflammatory challenge, intramuscular anabolic signaling, and muscle protein synthesis, and the effects of alcohol on these processes are opposite that of RE. Furthermore, individuals who report more frequent exercise also report a greater frequency of binge drinking. However, few investigations exist regarding the effects of binge alcohol consumed after a bout of RE on RE-induced physiological changes and performance recovery. Therefore, the overarching purpose of the investigations contained within this dissertation was to investigate the effect of alcohol consumed after RE on the RE-induced changes in mTOR pathway signaling, muscle protein synthesis, inflammatory capacity, strength recovery, and power recovery. Although RE increased mTOR pathway signaling and inflammatory capacity after exercise and reduced maximal strength and explosive power the day after exercise, we observed no effects of alcohol (1.09 g ethanol∙kg-1 lean body mass, designed to result in a peak blood alcohol concentration of approximately 0.12 g∙dl-1) consumed after RE on mTOR pathway signaling, 24-hour rates of muscle protein synthesis, inflammatory capacity, or strength and power recovery in resistance-trained individuals.
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Torssell, Staffan. "Amino Aacohols : stereoselective synthesis and applications in diversity-oriented synthesis." Licentiate thesis, KTH, Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-315.
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This thesis is divided into three separate parts with amino alcohols as the common feature. The first part describes the development of a novel three-component approach to the synthesis of α-hydroxy-β-amino esters. Utilizing a highly diastereoselective Rh(II)-catalyzed 1,3-dipolar cycloaddition of carbonyl ylides to various aldimines, syn-α-hydroxy-β-amino esters formed in high yields and excellent diastereoselectivities. This methodology was also applied in a short enantioselective synthesis of the C-13 side-chain of Taxol.
The second part of the thesis describes a total synthesis of D-erythro- Sphingosine based on a cross-metathesis approach to assemble the polar head group and the aliphatic chain.
The last part deals with the application of amino alcohols as scaffolds in a diversity-oriented protocol for the development of libraries of small polycyclic molecules. The design of the libraries is based on the iterative use of two powerful ring-forming reactions; a ring-closing metathesis and an intramolecular Diels-Alder reaction, to simultaneously introduce structural complexity and diversity.
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Akbayrak, Serdar. "Synthesis And Characterization Of Osmium(0) Nanoclusters And Their Catalytic Use In Aerobic Alcohol Oxidation." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612953/index.pdf.
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Transition metal nanoclusters are more active and selective catalysts than their bulk counterparts as the fraction of surface atoms increases with the decreasing particle size. When stabilized in organic or aqueous solutions, they can catalyze many reactions. The catalytic activity of metal nanoclusters depends on the particle size and size distribution. Particle size can be controlled by encapsulating the nanoclusters in the cavities of highly ordered porous materials such as zeolites. In this project, osmium(0) nanoclusters were formed within the void spaces of zeolite. Thus, nanoclusters of certain size were prepared as supported catalyst. Osmium(III) cations were introduced into the cavities of zeolite by ion exchange and were reduced partially or completely to form intrazeolite osmium(0) nanoclusters. The intrazeolite osmium(0) nanocusters were characterized by HRTEM, TEM, EDX, XPS, XRD, ICP-OES spectroscopic methods and N2 adsorption-desorption technique. Intrazeolite osmium(0) nanoclusters were employed as catalyst in the aerobic oxidation of alcohols in organic solution.
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Bourrier, Olivier E. "3, 5-Dihydroxybenzyl alcohol based dendrimers and hyperbranched polymers : synthesis, characterization and applications in catalysis." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84480.
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A new divergent methodology to prepare a variety of dendritic polymers containing dimethylsilyl-linked-3,5-dihydroxybenzyl alcohol units in the backbone is reported. This simple and versatile synthetic route is based on the acid-base hydrolytic chemistry of 3,5-dihydroxybenzyl alcohol (DHBA) and dimethyldiaminosilane Me2Si(NMe2)2. Controlled sequential addition of reactants was used to prepare dendrimer generations 1--5. The dendritic growth was found to be dictated by a preferential attack of the benzylic hydroxyl group of DHBA on the aminosilane, as no traces of residual benzylic OH groups were observed using 1H NMR spectroscopy. By a continuation of this divergent route, these dendrimers were functionalized with a variety of terminal units, including trimethylsilyl, n-octanoate, organic dye disperse red 1, and hydroxypropyldiphenylphosphine. Uncontrolled reaction protocols using the same reacting partners were also investigated to prepare the corresponding hyperbranched polymers. Resulting macromolecules showed structural fragments ranging from that of dendrimer generation 1 to that of dendrimer generation 2 in their MALDI-TOF mass spectra. Addition of more reactants did not seem to increase the size of these hyperbranched polymers.Determination of some of the structure-property relationships in these dendrimers was carried out to obtain a better understanding of their potential applications. Hydrolytic stability of the dendrimers was examined using dendrimer generations 1--3 solvated in wet DMSO. Their resistance towards hydrolysis was found to increase with an increase in generation number. Intrinsic viscosities were determined for dendrimer generations 1--5. A non-linear relationship was found between the generation number and the intrinsic viscosity, as it reached a maximum for dendrimer generation 4, followed by a decrease. 3,5-dihydroxybenzyl alcohol based dendrimers were found to self-assemble via hydrogen bonding between terminally situated hydroxyl groups. This phenomenon was found to be dependent on their concentration in solution, and a critical aggregation concentration was determined at 3.7 mg mL-1 for dendrimer generations 1--3. Higher generation dendrimers showed aggregate formation at low concentrations as the number of peripheral OH groups was significantly increased.
By functionalizing dendrimers and hyperbranched polymers with hydroxypropyldiphenylphosphine ligands, followed by coordination with [Rh(COD)Cl], we were able to synthesize metallodendrimers and organometallic hyperbranched polymers, in which active organometallic fragments are present at the periphery. Their catalytic activity was assessed in hydrogenation of 1-decene. Conversion rates of decene into decane for metallodendrimers were found to be dependent on the time of reaction and the generation number. Maximum conversion rates were found after 5 h reaction time in each case.
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Wang, Yaquan. "New routes to Rh (and CeOâ†2-promoted) Rh/SiOâ†2 catalysts for alcohol synthesis." Thesis, Brunel University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359923.
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Klaas, Lutho Attwell. "Synthesis and characterization of binary Palladium based electrocatalysts towards alcohol oxidation for fuel cell application." University of the Western Cape, 2018. http://hdl.handle.net/11394/6448.
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Magister Scientiae - MSc (Chemistry)The anode catalyst is one of the important parts of the direct alcohol fuel cell (DAFC); it is responsible for the alcohol oxidation reaction (AOR) takes place at the anode side. Pd has been reported to have good alcohol oxidation reactions and good stability in alkaline solution. Better stability and activity has been reported for Pd alloyed catalysts when compared to Pd. Choosing a suitable alcohol also has an effect on the activity and stability of the catalyst. This study investigates the best catalyst with better AOR and the best stability and also looks at the better alcohol to use between glycerol and ethanol for the five in-house catalysts (20% Pd, PdNi, PdNiO, PdMn3O4 and PdMn3O4NiO on multi walled carbon nanotubes) using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectrometry (EIS) and chronoamperometry. HR-TEM and XRD techniques were used to determine the particle size and average particle size, respectively while EDS used to determine elemental composition and ICP was used to determine catalyst loading. It was observed from LSV that PdNiO was the most active catalyst for both ethanol and glycerol oxidation, and it was the most stable in ethanol while PdMn3O4 proved to be the most stable catalyst in glycerol observed using chronoamperometry. The best alcohol in this study was reported to be glycerol having given the highest current densities for all the inhouse catalysts compared to ethanol observed using LSV. From XRD and HR-TEM studies, particle sizes were in the range of 0.97 and 2.69 nm for XRD 3.44 and 7.20 nm for HR-TEM with a little agglomeration for PdMn3O4 and PdMn3O4NiO.
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Maumau, Rebecca. "Synthesis of binary and ternary Pd-based Nanocatalysts for alcohol oxidation in alkaline media for fuel cell application." University of the Western Cape, 2020. http://hdl.handle.net/11394/7731.
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>Magister Scientiae - MScThis study explores the use of UV-assisted reduction method to synthesise the catalysts, aiming at reducing synthesis time. The Pd and Au catalyst loading is kept at 5 wt% in order to reduce the cost associated with high loading (20 wt%) of platinum group metals. The synthesised catalysts have SnO2 incorporated in them for two purposes, one being to activate the chemical reaction by absorbing UV-light and the second one is to serve as a promoter for binary and ternary catalysts. All the synthesised electrocatalysts in this study were denoted as Au/10wt%SnO2-C, Au/15wt%SnO2-C, Au/20wt%SnO2-C, Au/40wt%SnO2-C, Au/60wt%SnO2-C, Pd/10wt%SnO2-C, Pd/15wt%SnO2-C, Pd/20wt%SnO2-C, Pd/40wt%SnO2-C, Pd/60wt%SnO2-C and PdAu/10wt%SnO2-C respectively. The UV-assisted reduction method was proved to be effective with the obtained results from TEM, SEM, XRD and electrochemical studies. TEM micrographs revealed nanoparticles of Pd, Au and SnO2 which were proved by the measured d-spacing values corresponding to the element’s structures. The measured average particle size ranged from 3.05 to 14.97 nm for the electrocatalysts. The XRD profiles confirmed the face centred cubic of Pd, Au and tetragonal structures of SnO2. These electrocatalysts showed varied activity towards the oxidation of alcohols namely, methanol, ethanol, ethylene glycol and glycerol in alkaline electrolyte The cyclic voltammetry results showed improved performance towards the oxidation of glycerol on Au-based electrocatalysts, highest current density of 22.08 mA cm-2 than on Pd-based electrocatalysts. Pd-based electrocatalysts were more active towards the oxidation of ethanol than Au-based electrocatalysts with the highest current density of 19.96 mA cm-2. The co-reduced PdAu on 10wt%SnO2-C electrocatalysts showed the lowest current density of 6.88 mA cm-2 for ethanol oxidation when compared to Pd/10wt%SnO2-C and Au/10wt%SnO2-C. Linear sweep voltammograms showed more negative onset potentials on Pd-based electrocatalysts than Au-based electrocatalysts. The more negative onset potential obtained on Pd-based electrocatalysts was observed for ethanol oxidation. These results correspond to the trend observed in literature for ethanol oxidation being more favoured on Pd-based electrocatalysts whereas the polyalcohol oxidation is more favoured on Au-based electrocatalysts. The best performing and most stable electrocatalyst among the Au-based electrocatalysts is Au/10wt%SnO2-C and Pd/10wt%SnO2-C for the Pd-based electrocatalysts.
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Haas, Julian [Verfasser], Michael [Akademischer Betreuer] Müller, and Stefan [Akademischer Betreuer] Weber. "Alcohol Dehydrogenase-catalyzed oxidations for regio- and stereoselective synthesis of triketides = Alkoholdehydrogenase-katalysierte Oxidationen für die Regio- und Stereoselektive Synthese von Triketiden." Freiburg : Universität, 2017. http://d-nb.info/114725639X/34.
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Nebel, Janine Yasmine [Verfasser], Martin [Gutachter] Muhler, and Stefan [Gutachter] Kaluza. "Synthesis of multi-metallic catalysts applied in higher alcohol synthesis from syngas / Janine Yasmine Nebel ; Gutachter: Martin Muhler, Stefan Kaluza ; Fakultät für Chemie und Biochemie." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1199614505/34.
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Ohgi, Hiroyuki. "Studies on Synthesis and Physical Properties of Highly Isotactic Poly(vinyl alcohol) Derived from Poly(tert-butyl vinyl ether)." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/57290.
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Odabas, Serhat. "Asymmetric Synthesis Of N-aryl Substituted Chiral 1,4-amino Alcohol Derivatives And Applications In Various Asymmetric Transformation Reactions." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608489/index.pdf.
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The asymmetric synthesis of N-aryl substituted chiral 1,4-aminoalcohols and their applications in asymmetric borane reduction and enantioselective diethylzinc addition to benzaldehyde reactions were performed starting from meso anhydride 51 that is the cycloadduct of cyclopentadiene and maleic anhydride. The desymmetrization of meso-anhydride 51 was achieved by using quinine or quinidine with very high enantiomeric excess value (up to 98% ee) and with high chemicalb yield. The quinine-mediated desymmetrization of meso-anhydride 51 with methanol gave (2S,3R)-(-)-cis-monoester 52. The hemiester was subjected to chemoselective amidation with various types of N-aryl substituted amines and then, it was treated with LAH and followed by hydrogenation in the presence of palladium catalyst to get the chiral 1,4-amino alcohols. The catalytic effectiveness of these chiral 1,4-amino alcohol ligands, (2S,3R)-60, (2S,3R)-61, (2S,3R)-62 and (2S,3R)-63 were examined in asymmetric borane reduction and enantioselective diethylzinc addition to benzaldehyde reactions.
Keywords: Amino alcohol, chiral ligand, asymmetric reaction, borane reduction, diethylzinc addition
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Ekegren, Jenny. "Design and Synthesis of Novel HIV-1 Protease Inhibitors Comprising a Tertiary Alcohol in the Transition-State Mimic." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6737.
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Darabi, Hamed. "Altering the configuration of the secondary alcohol and quaternary carbon in pantothenate derivatives: synthesis of novel N-Pentylpantothenamides." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119530.
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The synthesis of pantothenamides with various but defined stereoconfigurations is promising for medicinal chemistry studies. N-pentylpantothenamides are antibacterial agents. Previous SAR studies reported an MIC of 3.6 µM against S. aureus for the allyl derivative with anti stereoconfiguration with respect to the secondary alcohol and the quaternary carbon. With the goal of improving the MIC, it was envisaged that compounds with the syn stereoconfiguration might have different activity. Thus a synthetic approach was developed which set the anti stereochemistry at the di alkyl germinal carbon via Frater's alkylation. Next the alcohol was oxidized to the ketone, and selectively reduced to generate the syn stereoconfiguration.Over the course of the synthesis of the syn stereoconfiguration, several different chemical and biocatlytic reducing agents were used. The chemical reducing agents tested were NaBH4, DIBAL-H, CBS and Zn2(BH4)2. None of these chemical reducing agents are able to overcome the energetic barriers of forming the syn product, instead favouring the formation of the anti product which is thermodynamically favoured. Interestingly with Baker's yeast the syn product is the major product. Next the scope of this reaction was studied by varying the alkyl chain at the quaternary carbon, ranging from small to large groups. Remarkably the Baker's yeast accepted a wide range of substrates. The compounds were finally extended to the full pantothenamide derivatives via the previously reported methodology. The final pantothenamide compounds will be tested for antibacterial activity, hopefully improving on the MIC of the parent compound. Furthermore these compounds have shown to be active antimalarial agents.La synthèse de pantothenamides avec des stéréoconfigurations variées mais définies est prometteur pour les études en chimie médicinale. Le N-pentylpantothenamide est un agent anti-bactérien. Des études SAR précédantes ont raporté un CMI de 3.6 µM contre S. aureus pour le derivative allyl avec stereoconfiguration anti de l'alcool secondaire et du carbone quartenaire. Avec le but d'améliorer le CMI, nous attendions que les composés avec la stereoconfiguration syn aurait une activité différemment. Ainsi, nous avons développé une nouvelle approche synthétique qui a mis la stéréochimie anti au carbone di alkyl via alkylation de Frater avant d'avoir oxidé l'alcool du cétone suivi par une réduction sélective afin de générer la stéréoconfiguration syn.Au cours de cette stratégie de synthèse pour développer la stéréoconfiguration syn, différentes agents réducteurs et réductions biocatalytiques, tel que la levure de Baker, ont été utilisées. Les agents réducteurs utilisé étaient NaBH4, DIBAL-H, CBS and Zn2(BH4)2 . Aucun de ces agents ont été capables de surmonter les barrières énergétiques nécessaire pour former le produit syn. À la place, la formation du produit anti est thermodynamiquement favorisée. Intéressamment, le levure de Baker donne le produit syn comme produit dominant. Ensuite, le potentiel de cette réaction a été exploré en variant la chaîne d'alkyl au carbone quartenaire, allant d'un petit à de larges groupes. La levure de Baker a accepté une grande variété de substrats.Au final, les composés ont été agrandi en dérivatifs de pantothenamide via la méthode précédente. Les panthothenamides finals seront testés pour activité antibactérienne dans l'espoir, d'améliorer la CMI du composé parent. De plus, ces composés ont démontré de l'activité antimalariale.
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Mayieka, Morgan Ongaga. "Attempted Azidation of Carbohydrate Secondary Alcohols Using Arylsulfonyl Azides." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1596709362791187.
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Erdem, Mine. "Asymmetric Synthesis Of Norbornene Based 1,4-aminoalcohol Derivatives And Applications In Asymmetric Diethylzinc Reactions." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608318/index.pdf.
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The asymmetric synthesis of chiral norbornene based 1,4-aminoalcohols and their applications in asymmetric diethylzinc addition reactions was perfomed starting from meso-anhydride 50. The desymmetrization of this meso-anhydride 50 was done by the usage of quinine or quinidine cinchona alkaloids with very high enantiomeric excess values (up to 98% ee) and chemical yields. The Quinidine-mediated desymmetrization of meso-anhydride 50 with methanol gave (2R,3S)-(+)-cis-monoester 51. The amination of this resulting compound with HMPTA was performed and by keeping the amine group constant, the amidoester was transformed into chiral ligands with Grignard reaction followed by LAH reduction.
The effectiveness of 1,4-aminoalcohol type ligands, (2R,3S)-(-)-57, (2R,3S)-(-)-58, (2R,3S)-(-)-59 and (2S,3R)-(+)-60 as chiral catalysts in asymmetric diethylzinc addition reaction to benzaldehyde were examined and the ligand 60 gave the highest enantioselectivity (69% e.e.)
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Axelsson, Linda. "Development of HIV-1 Protease Inhibitors and Palladium-Catalyzed Synthesis of Aryl Ketones and N-Allylbenzamides." Doctoral thesis, Uppsala universitet, Institutionen för läkemedelskemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-211672.
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The use of palladium-catalyzed reactions to introduce new carbon-carbon bonds is a fundamental synthetic strategy that has been widely embraced due to its high chemo- and regioselectivity and functional group tolerance. In this context, Pd(0)-catalyzed aminocarbonylations using Mo(CO)6 instead of toxic and gaseous CO and with allylamine as the nucleophile were investigated. The aminocarbonylated product dominated over the Mizoroki-Heck product, and (hetero)aryl iodides, bromides and chlorides gave N-allylbenzamides in good yields. In this thesis improvements to an existing protocol for the Pd(II)-catalyzed synthesis of aryl ketones from five benzoic acids and a variety of nitriles are also presented. Addition of TFA improved the yields and employing THF as solvent enabled the use of solid nitriles, and the aryl ketones were isolated in good yields. The pandemic of HIV infection is one of the greatest public health issues of our time and approximately 35.3 million people worldwide are living with HIV. There are currently many drugs on the market targeting various parts of the viral reproduction cycle, but the problems of resistance warrant the search for new drugs. HIV-1 protease makes the virus mature into infectious particles. In this thesis a new type of HIV-1 protease inhibitor (PI) is presented, based on two of the PIs on the market, atazanavir and indinavir, but it has a tertiary alcohol, as well as a two-carbon tether between the quaternary carbon and the hydrazide β-nitrogen. A total of 25 new inhibitors were designed, synthesized and biologically evaluated, the best compound had an EC50 value of 3 nM. Based on this series a project aimed at synthesizing macrocycles spanning the P1-P3 area was initiated. Macrocycles often tend to have an improved affinity and metabolic profile compared to their linear analogs. Introduction of a handle in the para position of the P1 benzyl group proved difficult, despite efforts to synthesize intermediates containing either a bromo-, hydroxy-, methoxy-, silyl-group protected hydroxy- or an alkyne-group. The lactone intermediate was abandoned in favor of an alternative synthetic route and initial studies were found to be promising. This new approach requires further investigation before the target macrocycles can be synthesized.
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Heuvel, Whitney. "Effect of precursor anion in alcohol/water solutions during hydro/solvothermal synthesis on cobalt oxide morphology and catalytic ability." Thesis, Cape Peninsula University of Technology, 2020. http://hdl.handle.net/20.500.11838/3046.
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Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2020The textile industry requires water for practically every step during its manufacturing process, and would benefit from water reuse systems. This is challenging, as the reactive dyes used in this industry often escape the conventional wastewater treatment methods used. The use of advanced oxidation processes combats these challenges, as it allows for the conversion of organic toxic waste to harmless H2O and CO2. Potassium peroxymonosulphate (Oxone®) has become popular in these treatment methods, as highly active sulphate radicals are activated once in contact with a transition metal. Such reactions are dependent on the catalyst used, and therefore require control of its morphology for enhanced capabilities. Cobalt oxide is deemed the best activator of peroxymonosulphate. The use of alcohols in its synthesis has been studied, but a systematic study increasing the alcohol chain lengths, in addition to the cobalt anion during hydro/solvothermal synthesis, has not been studied. Although the cobalt complex formed from cobalt chloride in water and alcohol has been studied, the use of these complexes as a precursor to cobalt oxide nanoparticles has not been studied. Cobalt hydroxide precursors were therefore synthesised in pure alcohol, pure water and alcohol/water solutions in the ratios 1:1 and 1:0. Five alcohols were selected, namely methanol, ethanol, propanol, butanol and octanol. and cobalt chloride hexahydrate and cobalt nitrate hexahydrate were used to study the effect of the anion. The effect of calcination temperature was also studied by varying it between 300°C and 500°C. The resulting particles were characterised using TEM, SEM, XRD, BET, EDS, FT-IR and ELNEFS, and its catalytic ability was tested treating a methylene blue solution in an in-house developed continuous reactor. Both α- and β-cobalt hydroxide polymorphs were encountered as precursors from cobalt chloride. The β-phase was evident when the water was exhausted from the system, whereas the α-phase was evident when water was present in the system. Only α-cobalt hydroxide was formed from cobalt nitrate. This provided a relationship between the cobalt complex formed to the phase of cobalt hydroxide polymorph. A blue, tetrahedral orientated precursor complex, produced pink β-cobalt hydroxide particles, while a red, octahedral orientated precursor complex, produced α-cobalt hydroxide. Cobalt oxide nanoparticles were formed from both α- and β-cobalt hydroxides. Anion morphology-dependent changes were observed in the presence of alcohol only. Rods were formed in the presence of the nitrate anion, while rhombic shapes dominated in the presence of chloride anions. Only rods were produced in water. An increase in the calcination temperature increased the crystallite size, which negatively affected the catalytic activity. It was also noted that a crystallite size between 8 and 11 nm resulted in highly active cobalt oxide particles for both anions explored. The catalytic ability of the cobalt oxide resulting from the β-phase was better than that of the α-phase. The best catalytic activity was produced by the cobalt oxide synthesised from cobalt chloride hexahydrate precursor salt in 100% methanol for which the ELNEFS analysis revealed a Co3+/Co2+ ratio of ten times that of its 50% counterpart.
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Almalki, Atiah Hassan. "Synthesis and Design of MS-153 Analogues as Potential Drugs for Treatment ofAlcohol and Methamphetamine Co-abuse." University of Toledo / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1497905762044506.
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Ratajczak, Fabien. "Synthèse et réactivité de nitroxydes chiraux." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10134.
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Les nitroxydes sont des radicaux libres qui sont reduits en hydroxylamine ou oxydes en sel d'oxoammonium par des processus monoelectroniques reversibles. Les sels d'oxoammonium formes in situ oxydent notamment les alcools primaires et secondaires dans des conditions douces, catalytiques, et sont chimio et regioselectifs. Pour tester leurs potentialites en synthese asymetriques, deux methodes de synthese de nitroxydes chiraux a axe de symetrie c#2 ont ete mises au point. La premiere methode, originale, met en jeu la formation de dienolates en ,' d'aminodiesters suivie de leur reaction avec des electrophiles. Le dedoublement des amines d,l obtenues suivie d'une oxydation mene aux nitroxydes chiraux cycliques (cinq et six chainons) enantiomeriquement enrichis. La seconde strategie comporte deux additions nucleophiles successives sur des nitrones. Les nitroxydes optiquement actifs sont obtenus via un dedoublement d'amines. Une version enantioselective de cette methode a ete developpee a partir de la nitrone issue de la (2r,5r)-dimethylpyrrolidine. La stabilite des sels d'oxoammonium resultant de l'oxydation des nitroxydes prepares a ete etudiee par electrochimie. Ils sont peu stables, mais formes in situ ils catalysent l'oxydation des alcools. Certains d'entre eux sont capables de reconnaissance chirale dans le cas du dedoublement cinetique d'un alcool racemique ou de l'oxydation asymetrique d'un diol meso. Les exces enantiomeriques sont actuellement modestes, mais quelques resultats sont prometteurs. Enfin le nouveau systeme d'oxydation d'alcools primaires par le couple ncs/tempo mis au point presente une chimioselectivite remarquable.
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Wieland, Laura Caroline. "Catalytic enantioselective synthesis of O- and N-substituted quaternary carbon stereogenic centers : 1. AL-catalyzed alkylations of α-ketoesters with dialkylzinc reagents. 2. AG-catalyzed vinylogous Mannich-type reactions of α-ketoimine esters with siloxyfurans." Thesis, Boston College, 2008. http://hdl.handle.net/2345/356.
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Thesis advisor: Amir H. HoveydaChapter 1: We disclose an Al-catalyzed enantioselective method for additions of Me2Zn and Et2Zn to α-ketoesters bearing aromatic alkenyl, and alkyl substituents. These transformations are promoted in the presence of a readily available amino acid-based ligand, and afforded the desired products in excellent yields and in up to 95% ee. In addition, we discovered a remarkable enhancement of efficiency and selectivity in the presence of an achiral phosphoramidate additive. Chapter 2: An efficient diastereo- and enantioselective Ag-catalyzed method for additions of a commercially available siloxyfuran to α-ketoimine esters is disclosed. Catalytic transformations require an inexpensive metal salt (AgOAc) and an air stable chiral ligand that is readily prepared in three steps from commercially available materials in 42% overall yield. Aryl- as well as heterocyclic substituted ketoimines can be used effectively in the Ag-catalyzed process. Additionally, two examples regarding reactions of alkyl-substituted ketoimines are presented. An electronically modified N-aryl group is introduced that is responsible for high reaction efficiency (>98% conversion, 72–95% yields after purification), diastereo- (up to >98:2 dr) and enantioselectivity (up to 97:3 er or 94% ee). The new N-aryl unit is also crucial for conversion of the asymmetric vinylogous Mannich products to the unprotected amines in high yields. Spectroscopic and X-ray data are among the physical evidence provided that shed light on the identity of the Ag-based chiral catalysts and some of the mechanistic subtleties of this class of enantioselective C–C bond forming processes
Thesis (PhD) — Boston College, 2008
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Sauca, Silvana. "Synthesis, characterization and application of polymeric flame retardant additives obtained by chemical modification." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/80716.
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A key part of the development of new polymeric materials focuses on the use of flame-retardant additives, which help to reduce the inherent flammability of polymers and the production of smoke and toxic gases.
The aim of this thesis was the preparation, characterization and application of new polymeric flame-retardant additives, which can lead to intumescent systems when mixed with ¨commodity¨ polymers. The synthesis of this kind of additives was carried out by chemical modification of different polymeric structures (alcohols, polyketones, polyaziridines) with phosphorous moieties, previously described as promoting flame retardance structures, and/or nitrogen containing moieties.
The efficacy of some of these additives was tested by blending with polypropylene, one of the most commonly used thermoplastic. Flame retardancy behaviour of the blends, as well their compatibility and mechanical properties were studied, in order to observe how the flame retardant additives may affect the substrate properties.Una parte fundamental del desarrollo de nuevos materiales poliméricos se centra en la utilización de agentes retardantes a la llama, los cuales contribuyen a reducir la inherente combustibilidad de los polímeros y la producción de humos y de gases tóxicos. El objetivo del presente trabajo ha sido la preparación, characterización y aplicación de nuevos aditivos retardantes a la llama de tipo polimérico que pueden dar lugar al mezclarse con polímeros termoplásticos de gran consumo a sistemas de tipo intumescente. La síntesis de estos additivos se ha llevado a cabo por modificación química de diferentes estructuras polimericas (alcoholes, policetonas, poliaziridinas) con compuestos fosforados, descritos previamente como promotores de retardancia a la llama y/o compuestos con nitrogeno. La eficacidad de algunos de estos additivos ha sido estudiada por mezclarse con polipropileno, uno de los más utilizados termoplasticos.
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Öhrngren, Per. "Tertiary Alcohol- or β-Hydroxy γ-Lactam-Based HIV-1 Protease Inhibitors : Microwave Applications in Batch and Continuous Flow Organic Synthesis." Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-160190.
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Since the outbreak of the HIV/AIDS pandemic in the 1980s, the disease has cost the lives of over 30 million people, and a further 33 million are currently living with the HIV infection. With the appropriate treatment, HIV/AIDS can today be regarded as a chronic but manageable disease. However, treatment is not available globally and UNAIDS still estimates that there are currently 5000 AIDS-related deaths worldwide per day. HIV protease inhibitors (PIs) constitute one of the fundaments of HIV treatment, and are commonly used in so-called highly active antiretroviral therapy (HAART), together with reverse transcriptase inhibitors. Although there are ten PIs on the market, there is still a need for novel structures. The rapid development of resistant strains, due to the high frequency of mutations, together with the commonly observed adverse effects of the drugs available, illustrate the need to develop new potent structures. Two novel scaffolds were investigated in this work. A tertiary alcohol-containing scaffold comprising a three-carbon tether, and a β-hydroxy γ-lactam-based scaffold were designed, synthesized and evaluated using enzyme- and cell-based assays. X-ray analyses of inhibitors from each class provided information on inhibitor–protease interactions. The inhibitors containing the tertiary alcohol provided at best an enzymatic inhibition (Ki) of 2.3 nM, and an inhibition in the cell-based assay (EC50) of 0.17 µM. The γ-lactam-based inhibitors exhibited better inhibition than the first series; the best values being Ki = 0.7 nM and EC50 = 0.04 µM. The second part of these studies involved the evaluation of a novel non-resonance continuous-flow microwave instrument. The instrument was validated regarding heating capacity, temperature stability and temperature homogeneity. A number of model reactions were performed with low- and high-microwave-absorbing solvents. It was found that the microwave heating source allowed rapid temperature adjustment, together with easily regulated, flow-dependent reaction times, providing an efficient tool for reaction optimisation.