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1

Haughan, Alan F. "Novel synthetic methods for preparation of cyclic compounds." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333955.

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2

Dixon, John Mark. "The conformational analysis of cyclic compounds by NMR spectroscopy." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293631.

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3

Khedhair, K. A. "The conformational analysis of cyclic compounds by spectroscopic methods." Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353919.

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4

Haq, Ahsanul. "The preparation of macrocyclic compounds by thermolysis of cyclic peroxides." Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/1491.

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5

Shirtcliff, Laura Donnell. "'Coarctate' cyclizations : applications to heterocycle synthesis /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1188876631&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 336-357). Also available for download via the World Wide Web; free to University of Oregon users.
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6

Contla, Hector Luna. "Cis-arenediols as versatile chiral synthons in the synthesis of prostaglandins, cyclitols, carbohydrates, and alkaloids /." This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134713/.

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7

Lo, Kai-yip, and 羅啟業. "Synthesis of aza-bicyclic compounds via palladium-catalyzed cascade cyclization reactions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47849691.

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 A palladium-catalyzed oxidative cascade cyclization reaction has been developed to prepare pyrrolizidine and indolizidine derivatives from simple aliphatic alkenyl amides 2.1ak in one step in moderate to good yields, using Pd(TFA)2 as the catalyst and molecular oxygen (1 atm) as a green oxidant. This cascade cyclization can also proceed for ring-containing unsaturated amides 2.1ln to afford azatricyclic systems. Palladium(II)-catalyzed dehydrohalogenation cascade cyclization reactions have been developed to synthesize polycyclic pyrrolizidine derivatives from iodoalkenylanilides 4.1ai in satisfactory to excellent yields under mild conditions. This reaction produces two stereocenters in one step and only one single diastereomer was obtained in the cyclization of 4.1. The reaction is proposed to proceed through an organopalladium(IV) species, formed by oxidative addition after the aminopalladation. This organopalladium(IV) species then undergoes reductive elimination to give the cyclized product. This cyclization is a fast and efficient way to construct natural alkaloids that contain pyrrolizidine or indolizidine cores.
published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
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8

Chu, Suk-ling. "The first synthesis and structure of diazatetrathiafulvalenes and some spectroscopic and cyclic voltammetric measurements /." [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13544548.

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9

Khumtaveeporn, Kanjai. "Rhodium catalyzed carbonylation and related reactions of nitrogen-, sulfur- and oxygen-containing cyclic and acyclic compounds." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10375.

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A systematic investigation has been carried out on the rhodium(I) catalyzed carbonylation of heterocyclic and acyclic compounds containing two heteroatoms at the 1,3-positions. The regioselectivities of carbon monoxide insertion are different in cyclic and acyclic compounds. When there is a choice between C-S and C-N bonds, in acyclic compounds, carbonylation of the C-N bond is more facile and the C-S bond is more easily carbonylated in acyclic compounds. When there is a possibility of ring or side chain carbonylation, it appears that the C-X bond of the side chain is more reactive. Rhodium(I) was also used to catalyze the carbonylation reaction of the N-O bond of isoxazolidine derivatives. When Ir-complexes were used as catalysts, the carbonylation occured and was followed by hydrogen transfer affording tetrahydro-1,3-oxazines as the final products. It was also found that substituents on the isoxazolidines have a dramatic effect on the reactivity of these substrates.
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10

Sutivisedsak, Nongnuch. "Synthesis of [alpha]-hydroxy and fluoro phosphonates and cyclic ether-containing natural products." Diss., St. Louis, Mo. : University of Missouri--St. Louis, 2008. http://etd.umsl.edu/r3246.

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11

朱淑玲 and Suk-ling Chu. "The first synthesis and structure of diazatetrathiafulvalenes and somespectroscopic and cyclic voltammetric measurements." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31211392.

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12

Wieczysty, Martin David. "C-H functionalisation of 2-aryl cyclic 1,3-dicarbonyl compounds ; Enantioselective Rh(I)-catalysed cyclisation of arylboron compounds onto ketones." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/18741.

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1. C–H Functionalisation of 2 Aryl Cyclic 1,3-Dicarbonyl Compounds Two enolate-directed C–H functionalisation protocols have been developed using 2-aryl cyclic 1,3-dicarbonyl compounds as substrates. Reactions with activated alkenes, under ruthenium or palladium catalysis produced benzopyrans in most cases, in moderate to good yield. Alternatively, an oxidative annulation of 2-aryl cyclic 1.3-dicarbonyls with 1,3-enynes was facilitated under rhodium catalysis, forming functionalised spiroindene structures in most cases, in generally good yields and high regioselectivity. During the investigation, the serendipitous formation of spirodialin structures was also observed. 2. Enantioselective Rh(I)-Catalysed Cyclisation of Arylboron Compounds onto Ketones Chiral tertiary alcohols, bearing aza-, oxa- and carbocyclic core structures of varying ring size were successfully formed from arylboron substrates under rhodium catalysis. In general the reactions proceeded with good yield and with moderate to high enantioselectivity. A protocol for the formation of a bicyclic lactam system was also achieved in moderate yield and enantioselectivity.
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13

Altun, Yasemin. "Addition Of Carbonyl Compounds To The Cyclic Olefins: Synthesis Of Cyclitols." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610117/index.pdf.

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ABSTRACT ADDITION OF CARBONYL COMPOUNDS TO THE CYCLIC OLEFINS: SYNTHESIS OF CYCLITOLS Altun, Yasemin M.S., Department of Chemistry Supervisor: Prof. Dr. Metin Balci October 2008, 160 pages Cyclitols have attracted a great deal of attention in recent years owing to biological activities exhibited by them and also their usefulness in the synthesis of other natural products and pharmaceuticals. Carbasugars are also a derivative of cyclitols and they are cyclic monosaccharide analogues which posses &
#8211
CH2OH group in their structure. In this study, novel synthetic strategies leading to cyclitol derivatives were investigated and the synthesis of tetraol (72) and pentaol (73) derivatives containing &
#8211
CH2OH group were achieved successfully. Moreover, by the use of manganese(III) acetate oxidation reactions having considerable synthetic utilities in organic chemistry we developed new synthetic methodologies for the cyclitol derivatives. 1,3- and 1,4-Cyclohexadiene (71 and 10) were synthesized from easily available starting materials in order to be used as key compounds. The use of manganese(III) acetate oxidation reaction provides the creation of &
#8211
CH2OH group and one of the hydroxyl groups and the remaining hydroxyl groups were introduced into the key compounds by the use of singlet oxygen reaction. As a result of this, we had considerable advance in the synthesis of cyclitol derivatives.
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14

Owino, Norbert Oduor. "Development of synthetic methods for the preparation of cyclobutenes and glycopeptides." Diss., Online access via UMI:, 2004. http://wwwlib.umi.com/dissertations/fullcit/3150497.

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15

Cadou, Romain F. "Studies in cyclic ether synthesis : Part one: Domino cyclisations to cyclic ethers -- Part two: Synthetic studies towards neopeltolide." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1025.

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Tetrahydrofuran (THF) and tetrahydropyran (THP) rings are commonly found in a wide range of natural products and biologically active compounds. In total synthesis, the formation of THF/THP motifs is often the key step but existing methods often involve numerous steps and low overall efficiencies. Part one of this thesis details the development of a practical method for the synthesis of THF rings by the controlled mono-addition/cyclisation of organolithium species to C2-symmetric diepoxides (Scheme A-1). This method can also be applied to the synthesis of bis-THF rings from triepoxides and has potential applications in more complex cascade reactions. A similar cyclisation process providing THF rings from epoxyaldehydes is also described. Part two of this thesis details our efforts towards the synthesis of the marine macrolide neopeltolide. Wright and co-workers reported the isolation of neopeltolide 211 from a deep-water sponge of the family neopeltidae off the north coast of Jamaica. The structure, which was assigned by NMR and HRMS studies and reassigned by total synthesis, contains a 14-membered macrolactone, a 2,6-cis THP ring and an unsaturated oxazole side-chain. Chapter four describes the synthesis of the C2-C8 and C9-C16 fragments (Scheme A-2). Chapter five details our initial attempts in the coupling of subunits 268 and 320, as well as a revised synthetic strategy that allowed us to successfully couple C2-C9 alkyne 347 with C10-C16 aldehyde 348 and the preparation of an advanced intermediate 364 (Scheme A-3).
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16

Hess, Euodia. "Boron-doped Diamond Sensors for the Determination of Organic Compounds in Aqueous Media." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5310_1305022937.

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In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.

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17

Contla, Hector Luna. "cis-Arenediols as versatile chiral synthons in the synthesis of prostaglandins, cyclitols, carbohydrates, and alkaloids." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/38900.

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18

Pereira, Fernando Luiz Cardoso. "Aplicações sintéticas de β-enamino ésteres." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-19112015-162222/.

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Uma série de β-enamino ésteres foi submetida a reações de iodociclização ou lactonização mediada por iodo, fornecendo como produtos iodo-β-enamino ésteres cíclicos ou β-enamino lactonas, respectivamente. Os iodo-β-enamino ésteres cíclicos obtidos foram submetidos a reações de desidroiodação, fornecendo os correspondentes produtos de eliminação de HI a partir de iodociclos de cinco membros, e ciclopentanos trissubstituídos, a partir de anéis de seis membros. Esta última reação ocorreu por substituição nucleofílica intramolecular, em vez da esperada reação de desidroiodação. O efeito do N-substituinte, nestas reações, foi estudado para uma série de N-alquil e N-aril derivados, fornecendo dados que possibilitaram uma melhor compreensão dos mecanismos envolvidos. As β-enamino lactonas foram obtidas em baixos rendimentos, devido à formação de subprodutos decorrentes da poliiodação do substrato, e mostraram-se resistentes à redução da dupla ligação carbono-carbono por uma série de métodos testados. Um estudo de análise conformacional dos compostos bicíclicos nitrogenados também foi efetuado, através de dados espectroscópicos de RMN-1H e RMN-13C, com o auxílio de cálculos de mecânica molecular e semi-empíricos. Concluiu-se que em função do N-substituinte os biciclos adotam diferentes conformações preferenciais, o que altera significativamente seus perfis espectroscópicos.
A series of acyclic β-enamino esters was submitted to iodocyclization reactions or to iodine-mediated lactonization, leading to the corresponding cyclic iodo-β-enamino esters or β-enamino lactones. Dehydroiodination of the five-membered ring enamino esters furnished pyrrole, tetrahydroindole and hexahydroindole derivatives, under basic or neutral conditions. The six-membered ring enamino esters, when submitled to treatment with triethylamine, gave rise to trisubstituted cyclopentanes. This transformation occurred through an intramolecular nucleophilic substitution, instead of the expected dehydroiodination reaction. The effect of the N-substituent in these reactions was studied for a series for N-alkyl and N-aryl derivatives. The β-enamino lactones were obtained in poor yields, due to the poliiodination of the substrates, and showed to be resistent to reduction of the carbon-carbon double bond under several conditions. A study of conformational analysis of the bicyclic β-enamino esters was undertaken, using 1H-NMR and13C-NMR data, molecular mechanics and semi-empirical methods. From this study, it was observed that the bicyclic compounds adopt different conformations depending upon the N-substituent.
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19

McKim, Artie S. "Synthesis and Alkali Metal Extraction Properties of Novel Cage-Functionalized Crown Coronands and Cryptands." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc277666/.

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20

Bohlin, Pernilla. "Passive sampling of PAHs and some trace organic compounds in occupational and residential air : needs, evaluation and limits /." Göteborg : Institute of Medicine at Sahlgrenska Academy, University of Gothenburg, 2010. http://hdl.handle.net/2077/2.

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21

Chen, Haoguo, and 陳浩國. "Silver catalyzed enyne cyclization reactions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841409.

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22

Chen, Haoguo. "Silver catalyzed enyne cyclization reactions." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841409.

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23

Teoh, Euneace Ching Mei. "Synthesis of amino acids by metal-catalysed reactions." Monash University, School of Chemistry, 2004. http://arrow.monash.edu.au/hdl/1959.1/9633.

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24

Nunes, Marta Regina dos Santos. "Ciclização eletrofílica de compostos β-enamino carbonílicos e β-dicarbonílicos." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-18092018-160100/.

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Esta tese consiste do estudo de reações de ciclofuncionalização de compostos β-enamino carbonílicos e β-dicarbonílicos, contendo uma cadeia alquenílica nas posições α ou γ. Os eletrófilos empregados para este fim foram: iodo, brometo de fenilselenenila e tricloreto de p-metóxifeniltelurio. Os iodo-β-enamino ésteres e cetonas cíclicas, após desidroiodação mediada por base, levaram à formação dos correspondentes pirróis, indóis e aminobenzofuranos. A ciclização dos β-ceto ésteres e β-dicetonas levou a enol éteres e benzofuranos funcionalizados. Estes resultados, juntamente com outros obtidos em nosso grupo de pesquisa, foram utilizados em um estudo comparativo entre reagentes de iodo, selênio e telúrio frente a reações de ciclização eletrofílica de substratos β-dicarbonílicos.
This thesis presents a study of the cyclofunctionalization of β-enamino carbonyl and β-dicarbonyl compounds, substituted by an alkenyl group at the α or γ positions. Iodine, phenyl-selenenyl bromide and p-methoxyphenyltellurium trichloride were employed as the electrophilic reagent. The cyclic iodo-β-enamino esters and ketones, after base-promoted dehydroiodination, led to the corresponding pyrroles, indoles and aminobenzofurans. The cyclization of the β-keto esters and β-diketones afforded five- and six-membered enol ethers and benzofuranones. These results, together with others previously obtained in our research group, allowed us to compare the behavior of the three above mentioned electrophiles toward the cyclofunctionalization of β-dicarbonyl substrates.
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25

Planas, i. Grabuleda Marta. "Síntesi de 1-oxaspiro [4.4]nonans polifuncionalitzats i (+-)-andirolactona." Doctoral thesis, Universitat de Girona, 1996. http://hdl.handle.net/10803/96652.

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Spiro-γ-lactones are widely distributed among natural products, several of them being well known by their interesting biological activities. We describe herein the synthesis of 1-oxaspiro[4.4]nonan derivatives and (+-)-andirolactone starting from easily available Diels-Alder adducts of 5-methylene-2(5H)-furanome 1 and classical dianes
La química de les espiro-γ-lactones ha despertat un considerable interès principalment degut a què moltes molècules que posseeixen aquesta estructura presenten diverses i significatives activitats biològiques. En aquesta tesi doctoral, prenent com a precursors els adductes de Diels-Alder, s’han investigat noves rutes sintètiques cap a 2(3H)-dihidrofuanones 5.5-disubstituïdes i oxaspiro[4.4]nonans polifuncionalitzats. Es presenten dues noves síntesis de (+-)-andirolactona 2, sesquiterpenoid amb estructura d’espiro-γ-butirolactona, recentment aïllat del Cedrus Libanotica i interessant per les seves propietats medicinals i biològiques potencials
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26

Aybey, Asuman. "Synthesis Of Chiral Lactones Via The Baeyer Villiger Oxidation Of Cyclic Aromatic Acetoxy Ketones Novel Annulation Reactions Of 2-propynyl-1,3-dicarbonyl Compounds To Form Pyrroles Addition Of Acyl Phosphonates To Diethyl Cyanophosphonate (depc)." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610293/index.pdf.

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Chiral Baeyer-Villiger (BV) oxidation of cyclic ketones allows rapid access to asymmetric lactones as valuable intermediates in organic chemistry and frequently encountered precursors in enantioselective synthesis. In the first part, BV oxidation of functionalized ketones, especially cyclic &
#61537
-hydroxy and acetoxy ketones is described which could be a straightforward route to the &
#61537
-hydroxy lactones and &
#61537
-hydroxyalkanoic acid derivatives. The &
#61537
-acetoxylation of indanone, tetralone and chromanone derivatives by using Mn(OAc)3 followed by the enzyme catalyzed kinetic resolution of acetoxy ketones gives both of the enantiomers of &
#61537
-acetoxy ketones in good chemical and optical yields. The Bayer-Villiger oxidation of &
#61537
-acetoxy ketones with m-CPBA, CF3SO3H, and CH2Cl2, at rt gives the corresponding lactones without racemization. The phenyl moiety migrates selectively in order to form lactones. The mild hydrolysis of lactones affords phenolic &
#61537
-hydroxycarboxylic acid derivatives. Because of the high importance of pyrrole derivatives which exist in the structure of many natural products possessing biological activity beside their valuable feature of being versatile building blocks in organic synthesis and important starting materials for various synthetic transformations, a convenient method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds throuh acid catalyzed cyclization reaction is presented in the second part of the thesis. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of trifluoroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The third part of the thesis describes the cyano-phosphorylation of various alkyl and aryl phosphonates in the presence of diethyl cyanophosphonate (DEPC) as the phosphorylating agent under the promotion of the KCN catalyst. Reaction of acyl phosphonates with DEPC forms the phosphonocyanohydrin-O-phosphates which are the important starting materials of quaternary &
#945
-hydroxy carboxylic acid and phosphonate containing &
#946
-aminoalcohol derivatives.
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27

Clark, Lauren Lisa. "Composition and cycling of marine organic phosphorus /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.

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28

Cerveri, Alessandro <1993&gt. "New catalytic strategies for the synthesis of complex (hetero)-cyclic compounds." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10102/1/Tesi_Cerveri_final.pdf.

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The aim of this Doctoral Thesis is the development of new catalytic transformation for efficient and sustainable processes, with the main purpose of easily access the incredible diversity and complexity of bio-relevant compounds. The tuning of general synthetic strategies is a flourishing field in organic chemistry, and can rapidly give access to libraries of products with small to big modifications from a hypothetical lead compound. Whit this in mind, in the modern era of organic synthesis, many aspects are pivotal in the design of a new catalytic procedure, such as reproducibility, generality over the main functional groups, mild conditions and easily accessible starting materials and catalysts. Particularly, another fundamental aspect is the generation of complexity in one single step, to conveniently assemble the scaffold of the class of compounds studied. During the course of my PhD, two main strategies were analyzed to tackle these challenges, namely de-aromatization and ring construction through cyclization. These methodologies have been deeply investigated both in organo- and metal-catalyzed fashions, and conceptually new protocols have been developed. Particular attention has been devoted at the study and optimization of the reaction conditions and catalyst structure, in order to maximize yield and selectivity of the processes as well as minimizing the catalyst loading and using the mildest conditions. The substrate scope has been thoroughly investigated to demonstrate the broad applicability of the proposed transformations, as well as the performance of synthetic elaborations illustrating the usefulness of the developed methods. Despite the conceptual diversity, the proposed protocols are connected by their potential further development into useful tools for the bio-molecule synthetic scenario.
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29

Frankki, Sofia. "Association of organic compounds to dissolved and particulate natural organic matter in soils /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200652.pdf.

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30

GABRIELLI, Serena. "Aliphatic Nitro compounds as Key Starting Materials for the One-Pot Synthesis of Cyclic and Heterocyclic Fine Chemicals." Doctoral thesis, Università degli Studi di Camerino, 2011. http://hdl.handle.net/11581/401849.

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31

Sosa, Oscar Abraham. "Microbial cycling of marine high molecular weight dissolved organic matter." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/104332.

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Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Microorganisms play a central role mediating biogeochemical cycles in the ocean. Marine dissolved organic matter (DOM) - a reservoir of organic solutes and colloids derived from plankton is a major source of carbon, nutrients, and energy to microbial communities. The biological transformation and remineralization of DOM sustains marine productivity by linking the microbial food web to higher trophic levels (the microbial loop) and exerts important controls over the cycles of carbon and bioessential elements, such as nitrogen and phosphorus, in the sea. Yet insight into the underlying metabolism and reactions driving the degradation of DOM is limited partly because its exact molecular composition is difficult to constrain and appropriate microbial model systems known to decompose marine DOM are lacking. This thesis identifies marine microorganisms that can serve as model systems to study the metabolic pathways and biochemical reactions that control an important ecosystem function, DOM turnover. To accomplish this goal, bacterial isolates were obtained by enriching seawater in dilution-to-extinction culturing experiments with a natural source of DOM, specifically, the high molecular weight (HMW) fraction (>1 kDa nominal molecular weight) obtained by ultrafiltration. Because it is relatively easy to concentrate and it is fairly uniform in its chemical composition across the global ocean and other aquatic environments, HMW DOM has the potential to serve as a model growth substrate to study the biological breakdown of DOM. The phylogeny, genomes, and growth characteristics of the organisms identified through this work indicate that HMW DOM contains bioavailable substrates that may support widespread microbial populations in coastal and open-ocean environments. The availability of ecologically relevant isolates in culture can now serve to test hypothesis emerging from cultivation-independent studies pertaining the potential role of microbial groups in the decomposition of organic matter in the sea. Detailed studies of the biochemical changes exerted on DOM by selected bacterial strains will provide new insight into the processes driving the aerobic microbial food chain in the upper ocean.
by Oscar Abraham Sosa.
Ph. D.
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32

Persson, Jörgen. "Organic nitrogen uptake by boreal forest plants /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s265-ab.html.

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33

Arnaout, Abdulkarim al. "Synthese regioselective de dihydropyridines et de pyridines 2- ou 4-fonctionnalisees : applications." Poitiers, 1987. http://www.theses.fr/1987POIT2254.

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34

Кузнецова, Катерина Ігорівна. "Одержання пероксидів та мономерів на основі оксигеновмісних гетероциклів та їх властивості." Diss., Національний університет "Львівська політехніка", 2021. https://ena.lpnu.ua/handle/ntb/56454.

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Дисертація присвячена синтезу пероксидів та мономерів на основі оксигеновмісних гетероциклічних сполук. Завдяки тому, що останні сполуки з малим розміром циклу та їх похідні мають достатньо високу реакційну здатність,на їх основі було одержано пероксидовмісні сполуки. В роботі синтезовано ряд оксигеновмісних гетероциклів, таких як оксетани, тетрагідрофурани, 1,3-діоксолани, 1,3-діоксани з різноманітними функціональними групами та досліджено реакції одержаних сполук з гідропероксидами та функціональними пероксидами як із збереженням гетероциклічного фрагменту, так і за його участю. Також на основі синтезованих сполук розроблено методи синтезу поверхнево-активних реакційноздатних олігомерів-ініціаторів з регулярним розміщенням вздовж макромолекулярного ланцюга ініціюючих центрів. Було вивчено властивості отриманих пероксидів та мономерів і запропоновано шляхи їх застосування. Детально досліджено реакції ооксигеноння циклічних кетонів гідроген пероксидом та трет-бутилгідропероксидом в лужному середовищі, запропоновано одержання поверхнево-активних речовин на основі продуктів реакцій. Диссертация посвящена синтезу пероксидов и мономеров на основе кислородсодержащих гетероциклических соединений. Благодаря тому, что последние соединения с малым размером цикла и их производные имеют достаточно высокую реакционную способность, на их основе было получено пероксидсодержащие соединения. В работе синтезирован ряд кислородсодержащих гетероциклов, таких как оксетаны, тетрагидрофураны, 1,3-диоксоланы, 1,3- диоксаны, с различными функциональными группами; исследованы реакции полученных соединений с гидропероксидами и функциональными пероксидами как с сохранением гетероциклического фрагмента, так и с его участием. Также на основе синтезированных соединений разработаны методы синтеза поверхностноактивных реакционно-способных олигомеров-инициаторов с регулярным расположением вдоль макромолекулярной цепи инициирующих центров. Было изучено свойства полученных пероксидов и мономеров и предложены пути их применения. Подробно исследованы реакции окисления циклических кетонов гидроген пероксидом и трет-бутилгидропероксидом в щелочной среде, предложены методы синтеза поверхностно-активных веществ на основе продуктов реакций. The dissertation is devoted to the synthesis of peroxides and monomers on the basis of oxygen - containing heterocyclic compounds. Due to the fact that the latter compounds with a small cycle size and their derivatives have a sufficiently high reactivity, peroxidecontaining compounds were obtained on their basis. A number of oxygen-containing heterocycles, such as oxetanes, tetrahydrofurans, 1,3-dioxolanes, 1,3-dioxanes with various functional groups, were synthesized in the work and the reactions of the obtained compounds with hydroperoxides and functional peroxides were investigated both with preservation of its heterocyclic moiety and. Methods for the synthesis of surface-active reactive oligomers-initiators with regular placement along the macromolecular chain of initiating centers have also been developed on the basis of the synthesized compounds. The properties of the obtained peroxides and monomers were studied and ways of their practical use were proposed. The oxidation reactions of cyclic ketones with hydrogen peroxide and tert-butyl hydroperoxide in an alkaline medium have been studied in detail, and the preparation of surfactants based on the reaction products has been proposed. New structures of surfactants have been proposed, in particular with the alternative placement of hydrophilic and hydrophobic blocks in the molecule, which contain peroxide groups in the side branches of the chain, and methods for their synthesis based on peroxide-containing oxetanes have been developed. New types of reactive surfactants have been developed that can be used as macroinitiators in the processes of obtaining amphiphilic polymers of complex architecture.
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35

Follett, Christopher L. "Heterogeneous reservoirs in the marine carbon cycle." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90666.

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Thesis: Ph. D., Joint Program in Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2014.
122
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 149-158).
Understanding the fate of primary production in the ocean is a challenging task because once produced, organic material is oxidized over timescales which range from minutes, to millions of years. This timescale diversity is matched by an equal heterogeneity in both the local physical and chemical environment. In this thesis we explore the relationship between the distinct reservoirs of organic carbon in the ocean and their underlying complexity. First, we show how the heterogeneity of portions of the carbon cycle can be packaged in terms of age structured models and their accompanying age and rate distributions. We further relate the moments of the rate distributions to bulk reservoir properties like average age and flux. Explicit relationships are then derived for the specific case of a single turnover time and a lognormal distribution. We apply these ideas to the problem of dissolved organic carbon (DOC) cycling in the ocean. Current models of bulk concentration and isotope data suggest a microbially sourced DOC reservoir consisting of two components. A nearly homogeneous background component with a long turnover time (> 6000 years) is joined by a component of fast turnover time (~ 1 year) and equal concentration in the surface ocean. We confirm the presence of isotopically enriched, modern DOC co-cycling with an isotopically depleted older fraction in the upper ocean. However, our results show that up to 30% of the deep DOC reservoir is modern and supported by a 1 Pg per year carbon flux, ten times higher than inferred from bulk isotope measurements. Isotopically depleted material turns over at an apparent time scale of 30, 000 years, far slower than indicated by bulk isotope measurements. These results are consistent with global DOC measurements and explain both the fluctuations in deep DOC concentration and the anomalous radiocarbon values of DOC in the Southern Ocean. Finally, the thesis explores methods for determining the validity of diffusion limitation as the mechanism behind the power-law slowdown in organic remineralization in sediment. We find that diffusion limitation connects the decay behavior of organic material to the correlations found between mineral surface area and organic matter content in sediments.
by Christopher L. Follett.
Ph. D.
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36

Materechera, Simeon Albert. "The influence of soil organic matter on changes in leaf water potential of barley (Hordeum vulgare L.) during repeated cycles of moisture stress /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63288.

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37

Voss, Britta Marie. "Spatial and temporal dynamics of biogeochemical processes in the Fraser River, Canada : a coupled organic-inorganic perspective." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/95521.

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Thesis: Ph. D., Joint Program in Chemical Oceanography (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2014.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
The great geologic and climatic diversity of the Fraser River basin in southwestern Canada render it an excellent location for understanding biogeochemical cycling of sediments and terrigenous organic carbon in a relatively pristine, large, temperate watershed. Sediments delivered by all tributaries have the potential to reach the ocean due to a lack of main stem lakes or impoundments, a unique feature for a river of its size. This study documents the concentrations of a suite of dissolved and particulate organic and inorganic constituents, which elucidate spatial and temporal variations in chemical weathering (including carbonate weathering in certain areas) as well as organic carbon mobilization, export, and biogeochemical transformation. Radiogenic strontium isotopes are employed as a tracer of sediment provenance based on the wide variation in bedrock age and lithology in the Fraser basin. The influence of sediments derived from the headwaters is detectable at the river mouth, however more downstream sediment sources predominate, particularly during high discharge conditions. Bulk radiocarbon analyses are used to quantify terrestrial storage timescales of organic carbon and distinguish between petrogenic and biospheric organic carbon, which is critical to assessing the role of rivers in long-term atmospheric CO2 consumption. The estimated terrestrial residence time of biospheric organic carbon in the Fraser basin is 650 years, which is relatively short compared to other larger rivers (Amazon, Ganges-Brahmaputra) in which this assessment has been performed, and is likely related to the limited floodplain storage capacity and non-steady-state post-glacial erosion state of the Fraser River. A large portion of the dissolved inorganic carbon load of the Fraser River (>80%) is estimated to derive from remineralization of dissolved organic carbon, particularly during the annual spring freshet when organic carbon concentrations increase rapidly. This thesis establishes a baseline for carbon cycling in a largely unperturbed modern mid-latitude river system and establishes a framework for future process studies on the mechanisms of organic carbon turnover and organic matter-mineral associations in river systems.
by Britta Marie Voss.
Ph. D.
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38

Tougani, Rajaallah Amina. "Acylation d'énolates lithiens d'esters et d'organozinciques allyliques : obtention de composés carbonyles fonctionnels et utilisation de ces derniers à la synthèse d'hétérocycles oxygénés à cinq chainons." Paris 6, 1986. http://www.theses.fr/1986PA066522.

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39

Bedioui, Fethi. "Etude électrochimique de complexes de métaux de transition (bases de Schiff et porphyrines) en solution et sous forme d'électrodes modifiées : application à la catalyse électroassistée de réactions organiques." Paris 6, 1986. http://www.theses.fr/1986PA066338.

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Les propriétés électrochimiques des complexes co-base de Schiff (phenylene-bis(salicylideneiminoto)-co, ou Co(II)saloph, et n-methylenepropylene-bis-(salicylideneiminoto)-co, ou co-selnmedpt) et de tetraphenylporphine-co, ou CoTPP, sont utilisées pour étudier la réduction électroassistée d'halogénures organiques, Rx, avec un catalyseur fixe sur support conducteur, en milieu organique. On étudie: 1) la réduction du chlorure de benzyle électrocatalysée par des électrodes de graphite modifiées par du co-saloph et 2) l'oxydation par l'oxygène moléculaire du di-tert-butylphenol, électrocatalysée par des films de polypyrrole contenant la porphyrine mntcpp.
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40

COSTA, LUZIA B. O. "Avaliação do ciclo de vida da produção de biogás via estação de tratamento de esgoto e uso em célula a combustível de óxido sólido." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10102.

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Made available in DSpace on 2014-10-09T12:34:47Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:03:29Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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41

Allioux, Maxime. "Etudes physiologiques et multi-omiques de métabolismes du soufre présents dans les écosystèmes hydrothermaux : Physiological and multi-omics studies of microbial sulfur metabolisms present in hydrothermal ecosystems." Thesis, Brest, 2021. https://tel.archives-ouvertes.fr/tel-03789624.

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Les cheminées hydrothermales hébergent une vaste diversité microbienne, tant au niveau taxonomique qu’au niveau métabolique. Ces écosystèmes sont qualifiés d’extrêmes, en raison des très larges gradients physicochimiques qu’ils abritent. Le soufre y est un élément omniprésent, il peut être utilisé par une large diversité de microorganismes pour des réactions d’oxydations ou de réductions. Cependant, le cycle du soufre reste partiellement méconnu au sein de ces écosystèmes. L’objectif de cette thèse était d’étudier les métabolismes du cycle du soufre peu documentés ou simplement prédits par la thermodynamique, au sein des écosystèmes hydrothermaux, à savoir la dismutation des composés inorganiques soufrés, le catabolisme des composés organosoufrés et le comproportionnement du soufre. Quatre nouveaux taxons dismutant les composés inorganiques soufrés ont été découverts au cours de cette étude et des analyses génomiques approfondies ont été menées pour décrypter les voies de la dismutation des composés inorganiques soufrés. Des analyses en génomique comparative ont permis d’identifier un cluster de gènes potentiellement impliqué dans la dismutation du soufre élémentaire chez des bactéries hydrothermales marines, mais ce résultat nécessitera d’être confirmé par des approches fonctionnelles. Enfin, les communautés microbiennes de sources chaudes des îles Kerguelen très isolées géographiquement ont été étudiées par métagénomique, ce qui a révélé la présence de nombreuses nouvelles lignées de bactéries et d’archées dans ces habitats jamais étudié auparavant
Hydrothermal vents host a vast microbial diversity, both at the taxonomic and metabolic levels. These ecosystems are qualified as extreme, because they harbor harsh physico-chemical gradients. Sulfur is omnipresent in these environments, and it can be used by a large diversity of microorganisms for oxidation or reduction reactions.However, the sulfur cycle remains partially unknown in these ecosystems. The objective of this thesis was to study the poorly documented or thermodynamically predicted metabolisms of the sulfur cycle in hydrothermal ecosystems, namely the dismutation of inorganic sulfur compounds, the catabolism of organosulfur compounds and the comproportionation of sulfur. Four new inorganic sulfur compound disproportionating taxa were discovered during this study and extensive genomic analyses were conducted to decipher the pathways of inorganic sulfur compound dismutation. Comparative genomics analyses identified a gene cluster potentially involved in elemental sulfur dismutation in marine hydrothermal bacteria, but this result will need to be confirmed by functional approaches.Finally, the microbial communities of the geographically isolated hot springs from the Kerguelen Islands were studied by metagenomics, revealing the presence of many new lineages of bacteria and archaea in these previously unstudied habitats
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42

Jachiet, Denis. "Reactivite des organocuprates et des organoaluminates associes a bf::(3) dans l'ouverture nucleophile des oxirannes : application a la synthese de pheromones." Paris 6, 1987. http://www.theses.fr/1987PA066438.

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43

Cazot, Mathilde. "Development of Analytical Techniques for the Investigation of an Organic Redox Flow Battery using a Segmented Cell." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0116.

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Les batteries à électrolyte circulant ou redox flow batteries (RFB) représentent une technologie prometteuse pour répondre aux besoins grandissants de stockage d'énergie. Elles seraient particulièrement adaptées aux réseaux électriques qui comptent une part grandissante d'énergie d'origine renouvelable, produite en intermittence. L'objet de ce travail est l'étude d'un nouveau type de RFB, actuellement développé par l'entreprise Kemiwatt. Il repose sur l'utilisation de molécules organiques, qui sont abondantes et recyclables. Le but de cette étude est d'améliorer la compréhension fondamentale de la batterie grâce à l'utilisation d'outils d'analyse précis et innovants. Chaque composant du système a d'abord été analysé via des moyens expérimentaux ex-situ. Les deux électrolytes composant la batterie ont ensuite été étudiés séparément en conditions réelles de circulation dans une cellule symétrique. Couplées à un modèle d'électrode volumique, les données ont été analysées pour identifier les facteurs limitants de chaque solution. La batterie entière a ensuite été étudiée dans un dispositif segmenté, permettant l'accès à la distribution interne du courant. Une étude paramétrique, réalisée avec la cellule segmentée a permis d'observer les effets du courant, du débit et de la température sur le fonctionnement de la cellule, puis d'établir une cartographie des conditions de fonctionnement idéales, suivant la puissance et l'état de charge de la batterie. L'aspect hydrodynamique du système a finalement été abordé en développant un modèle fluidique ainsi qu'une maquette expérimentale de cellule transparente pour visualiser l'écoulement
Redox Flow Batteries (RFBs) are a promising solution for large-scale and low-cost energy storage necessary to foster the use of intermittent renewable sources. This work investigates a novel RFB chemistry under development at the company Kemiwatt. Based on abundant organic/organo-metallic compounds, this new technology promises the deployment of sustainable and long-lived systems. The study undertakes the building of a thorough knowledge base of the system by developing innovative reliable analytical tools. The investigation started from the evaluation of the main factors influencing the battery performance, which could be conducted ex-situ on each material composing the cell. The two electrolytes were then examined independently under representative operating conditions, by building a symmetric flow cell. Cycling coupled with EIS measurements were performed in this set-up and then analyzed with a porous electrode model. This combined modeling-experimental approach revealed unlike limiting processes in each electrolyte along with precautions to take in the subsequent steps (such as membrane pretreatment and electrolyte protection from light). A segmented cell was built and validated to extend the study to the full cell system. It provided a mapping of the internal currents, which showed high irregularity during cycling. A thorough parameter study could be conducted with the segmented platform, by varying successively the current density, the flow rate, and the temperature. The outcome of this set of experiments would be the construction of an operational map that guides the flow rate adjustment, depending on the power load and the state of charge of the battery. This strategy of flow rate optimization showed promising outcomes at the lab-cell level. It can be easily adapted to real-size systems. Ultimately, an overview of the hydrodynamic behavior at the industrial-cell level was completed by developing a hydraulic modeling and a clear cell as an efficient diagnostic tool
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44

Lazraq, Mohamed. "Derives doublement lies du bore, du phosphore et du germanium : phosphaborenes et germenes." Toulouse 3, 1988. http://www.theses.fr/1988TOU30141.

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De nouvelles methodes de synthese de diphosphadiboretannes-1,3,2,4 sont decrites. Un derive a double liaison bore-phosphore du type rb=par (avec r=tetramethyl-2,2,6,6 piperidyl et ar=tri-t-butyl-2,4,6 phenyl) a ete mis en evidence par piegeage in situ. Le premier derive stable a double liaison germanium-carbone a ete prepare: il s'agit du dimesityl fluoremylidene germane. Sa caracterisation a ete effectuee par diverses methodes physicochimiques et sa reactivite chimique, etudiee
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45

McKenney, Ryan Kenneth. "Emerging Therapeutics for Organophosphorus Nerve Agent Poisonings. The Development of a Fluoride Ion Battery System Utilizing Nanoparticles." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491830263330328.

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46

Cazot, Mathilde. "Development of Analytical Techniques for the Investigation of an Organic Redox Flow Battery using a Segmented Cell." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0116.

Full text
Abstract:
Les batteries à électrolyte circulant ou redox flow batteries (RFB) représentent une technologie prometteuse pour répondre aux besoins grandissants de stockage d'énergie. Elles seraient particulièrement adaptées aux réseaux électriques qui comptent une part grandissante d'énergie d'origine renouvelable, produite en intermittence. L'objet de ce travail est l'étude d'un nouveau type de RFB, actuellement développé par l'entreprise Kemiwatt. Il repose sur l'utilisation de molécules organiques, qui sont abondantes et recyclables. Le but de cette étude est d'améliorer la compréhension fondamentale de la batterie grâce à l'utilisation d'outils d'analyse précis et innovants. Chaque composant du système a d'abord été analysé via des moyens expérimentaux ex-situ. Les deux électrolytes composant la batterie ont ensuite été étudiés séparément en conditions réelles de circulation dans une cellule symétrique. Couplées à un modèle d'électrode volumique, les données ont été analysées pour identifier les facteurs limitants de chaque solution. La batterie entière a ensuite été étudiée dans un dispositif segmenté, permettant l'accès à la distribution interne du courant. Une étude paramétrique, réalisée avec la cellule segmentée a permis d'observer les effets du courant, du débit et de la température sur le fonctionnement de la cellule, puis d'établir une cartographie des conditions de fonctionnement idéales, suivant la puissance et l'état de charge de la batterie. L'aspect hydrodynamique du système a finalement été abordé en développant un modèle fluidique ainsi qu'une maquette expérimentale de cellule transparente pour visualiser l'écoulement
Redox Flow Batteries (RFBs) are a promising solution for large-scale and low-cost energy storage necessary to foster the use of intermittent renewable sources. This work investigates a novel RFB chemistry under development at the company Kemiwatt. Based on abundant organic/organo-metallic compounds, this new technology promises the deployment of sustainable and long-lived systems. The study undertakes the building of a thorough knowledge base of the system by developing innovative reliable analytical tools. The investigation started from the evaluation of the main factors influencing the battery performance, which could be conducted ex-situ on each material composing the cell. The two electrolytes were then examined independently under representative operating conditions, by building a symmetric flow cell. Cycling coupled with EIS measurements were performed in this set-up and then analyzed with a porous electrode model. This combined modeling-experimental approach revealed unlike limiting processes in each electrolyte along with precautions to take in the subsequent steps (such as membrane pretreatment and electrolyte protection from light). A segmented cell was built and validated to extend the study to the full cell system. It provided a mapping of the internal currents, which showed high irregularity during cycling. A thorough parameter study could be conducted with the segmented platform, by varying successively the current density, the flow rate, and the temperature. The outcome of this set of experiments would be the construction of an operational map that guides the flow rate adjustment, depending on the power load and the state of charge of the battery. This strategy of flow rate optimization showed promising outcomes at the lab-cell level. It can be easily adapted to real-size systems. Ultimately, an overview of the hydrodynamic behavior at the industrial-cell level was completed by developing a hydraulic modeling and a clear cell as an efficient diagnostic tool
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47

Owens, Stephanie Anne. "Advances in measurements of particle cycling and fluxes in the ocean." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79284.

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Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references.
The sinking flux of particles is an important removal mechanism of carbon from the surface ocean as part of the biological pump and can play a role in cycling of other chemical species. This work dealt with improving methods of measuring particle export and measuring export on different scales to assess its spatial variability. First, the assumption of ²³⁸U linearity with salinity, used in the ²³⁸U-²³⁴Th method, was reevaluated using a large sample set over a wide salinity range. Next, neutrally buoyant and surface-tethered sediment traps were compared during a three-year time series in the subtropical Atlantic. This study suggested that previously observed imbalances between carbon stocks and fluxes in this region are not due to undersampling by traps. To assess regional variability of particle export, surface and water-column measurements of ²³⁴Th were combined for the first time to measure fluxes on ~20 km scales. Attempts to relate surface properties to particle export were complicated by the temporal decoupling of production and export. Finally, particle export from ²³⁴Th was measured on transects of the Atlantic Ocean to evaluate basin-scale export variability. High-resolution sampling through the water-column allowed for the identification of unique ²³⁴Th features in the intermediate water column.
by Stephanie Anne Owens.
Ph.D.
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48

Laduranty, Joëlle. "Mise au point de la préparation de molécules polyfonctionnelles comportant l'unité structurale SCCN de la cystéamine : applications en radioprotection et synthèse organique." Poitiers, 1988. http://www.theses.fr/1988POIT2013.

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49

Soules, Régis. "Proprietes cooperatives de complexes polymetalliques des ligands squarate et thiosquarate." Toulouse 3, 1987. http://www.theses.fr/1987TOU30178.

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Etude de l'emploi d'un coordinat assembleur qui puisse par coordination avec le centre metallique utilise (metaux de transition du groupe viii) aboutir a un agencement a une dimension des motifs moleculaires par empilement d'entites monomeres ou par formation de chaines. Par utilisation du coordinat squarate sous ses formes oxygenees et soufrees, obtention d'un certain nombre de complexes de pt, pd, ni et cu repondant aux criteres fixes. Etude des structures de ces composes, de leurs proprietes physiques et de la relation structure-propriete. La nature du coordinat comme le caractere specifique de l'arrangement structural ont ete discutes pour une approche de la comprehension de la nature de ces proprietes physiques
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50

Réau, Régis. "Phospholes et phosphanorbornadienes : valorisation en catalyse homogene." Toulouse 3, 1988. http://www.theses.fr/1988TOU30162.

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Les ligands etudies ont ete utilises d'une part en association avec des complexes cationiques du palladium en reactions de dimerisation de l'acrylate de methyle, de codimerisation de l'acrylate de methyle et du butadiene-1,3 et de telomerisation de ce dernier avec le methanol; d'autre part en association avec des complexes de rhodium dans l'hydroformylation de l'hexene-1 de styrenes et de l'acrylate de methyle
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