Einloggen

Thematische Bibliographien / Carbon-Nitrozen bond(C-N) formation

Inhaltsverzeichnis

Zeitschriftenartikel
Dissertationen
Bücher
Buchteile
Konferenzberichte
Berichte der Organisationen

Auswahl der wissenschaftlichen Literatur zum Thema „Carbon-Nitrozen bond(C-N) formation“

Autor: Grafiati

Veröffentlicht am 18. Mai 2024

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an

Wählen Sie eine Art der Quelle aus:

Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "Carbon-Nitrozen bond(C-N) formation" bekannt.

Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.

Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.

Zeitschriftenartikel zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

Cataldo, Franco. „Cyanopolyynes: carbon chains formation in a carbon arc mimicking the formation of carbon chains in the circumstellar medium“. International Journal of Astrobiology 3, Nr. 3 (Juli 2004): 237–46. http://dx.doi.org/10.1017/s1473550404002149.

Der volle Inhalt der Quelle

Annotation:

Monocyanopolyynes and dicyanopolyynes can be synthesized quite easily by the submerged electric arc. Monocyanopolyynes having the general formula H[bond](C[triple bond]C)n[bond]C[triple bond]N can be synthesized together with ordinary polyynes series H[bond](C[triple bond]C)n[bond]H by arcing graphite electrodes in acetonitrile. Dicyanopolyynes N[triple bond]C[bond](C[triple bond]C)n[bond]C[triple bond]N are produced almost pure by arcing graphite electrodes directly into liquid nitrogen. These molecules are present in the envelope of post-AGB (asymptotic giant branch), carbon-rich giant stars and also in dark molecular clouds. They are incorporated into comets and also into other primitive materials and may play a role in the prebiotic synthesis of more complex organic molecules having a biological significance. Furthermore, the cyanopolyynes are involved in the atmospheric chemistry of some bodies of the solar system. The discovery of the easy formation of these molecules under laboratory conditions may explain why these molecules are so ubiquitous in space and may also stimulate new ideas about the mechanism of their formation.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Kärkäs, Markus D. „Electrochemical strategies for C–H functionalization and C–N bond formation“. Chemical Society Reviews 47, Nr. 15 (2018): 5786–865. http://dx.doi.org/10.1039/c7cs00619e.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Möhlmann, Lennart, Moritz Baar, Julian Rieß, Markus Antonietti, Xinchen Wang und Siegfried Blechert. „Carbon Nitride-Catalyzed Photoredox CC Bond Formation with N-Aryltetrahydroisoquinolines“. Advanced Synthesis & Catalysis 354, Nr. 10 (05.06.2012): 1909–13. http://dx.doi.org/10.1002/adsc.201100894.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Li, Jing-Yuan, Qing-Wen Song, Kan Zhang und Ping Liu. „Catalytic Conversion of Carbon Dioxide through C-N Bond Formation“. Molecules 24, Nr. 1 (05.01.2019): 182. http://dx.doi.org/10.3390/molecules24010182.

Der volle Inhalt der Quelle

Annotation:

From the viewpoint of green chemistry and sustainable development, it is of great significance to synthesize chemicals from CO2 as C1 source through C-N bond formation. During the past several decade years, many studies on C-N bond formation reaction were involved, and many efforts have been made on the theory. Nevertheless, several great challenges such as thermodynamic limitation, low catalytic efficiency and selectivity, and high pressure etc. are still suffered. Herein, recent advances are highlighted on the development of catalytic methods for chemical fixation of CO2 to various chemicals through C-N bond formation. Meanwhile, the catalytic systems (metal and metal-free catalysis), strategies and catalytic mechanism are summarized and discussed in detail. Besides, this review also covers some novel synthetic strategies to urethanes based on amines and CO2. Finally, the regulatory strategies on functionalization of CO2 for N-methylation/N-formylation of amines with phenylsilane and heterogeneous catalysis N-methylation of amines with CO2 and H2 are emphasized.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Kerru, Nagaraju, Suresh Maddila und Sreekantha B. Jonnalagadda. „Design of Carbon-carbon and Carbon-heteroatom Bond Formation Reactions under Green Conditions“. Current Organic Chemistry 23, Nr. 28 (17.01.2020): 3154–90. http://dx.doi.org/10.2174/1385272823666191202105820.

Der volle Inhalt der Quelle

Annotation:

: The development of C-C and C-heteroatom (C-N, C-O and C-P) bond reactions is a field of significant interest and has received momentous attention in modern organic chemistry. These reactions have been exploited in the synthesis of pharmaceuticals, agrochemicals and molecules of interest in materials science. With the increasing awareness of global warming and the use of renewable energies, it is of paramount importance to reduce the usage of hazardous chemicals in both industrial and academic research and to achieve a healthier environment through green practices. Green chemistry is a rapidly emerging approach that shows us a path for the sustainable growth of future science and technologies. In the recent past, healthy growth has been recorded in a number of organic reactions in aqueous media, which are environment-friendly and energy conserving. This review documents the literature on the development of green methodologies involving the design of C-C, C-O, C-N and C-P bond formations of coupling and condensed reactions. It emphasizes the exceptional practices and important advances achieved using alternative green tools, such as microwave (MW), high-speed ball milling (HSBM) and ultrasound irradiation techniques, and a variety of reusable catalysts and green solvents, with attention to water.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Moehlmann, Lennart, Moritz Baar, Julian Riess, Markus Antonietti, Xinchen Wang und Siegfried Blechert. „ChemInform Abstract: Carbon Nitride-Catalyzed Photoredox C-C Bond Formation with N-Aryltetrahydroisoquinolines.“ ChemInform 43, Nr. 50 (29.11.2012): no. http://dx.doi.org/10.1002/chin.201250155.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Kamanna, Kantharaju, und Santosh Y. Khatavi. „Microwave-accelerated Carbon-carbon and Carbon-heteroatom Bond Formation via Multi-component Reactions: A Brief Overview“. Current Microwave Chemistry 7, Nr. 1 (23.06.2020): 23–39. http://dx.doi.org/10.2174/2213346107666200218124147.

Der volle Inhalt der Quelle

Annotation:

Multi-Component Reactions (MCRs) have emerged as an excellent tool in organic chemistry for the synthesis of various bioactive molecules. Among these, one-pot MCRs are included, in which organic reactants react with domino in a single-step process. This has become an alternative platform for the organic chemists, because of their simple operation, less purification methods, no side product and faster reaction time. One of the important applications of the MCRs can be drawn in carbon- carbon (C-C) and carbon-heteroatom (C-X; X = N, O, S) bond formation, which is extensively used by the organic chemists to generate bioactive or useful material synthesis. Some of the key carbon- carbon bond forming reactions are Grignard, Wittig, Enolate alkylation, Aldol, Claisen condensation, Michael and more organic reactions. Alternatively, carbon-heteroatoms containing C-N, C-O, and C-S bond are also found more important and present in various heterocyclic compounds, which are of biological, pharmaceutical, and material interest. Thus, there is a clear scope for the discovery and development of cleaner reaction, faster reaction rate, atom economy and efficient one-pot synthesis for sustainable production of diverse and structurally complex organic molecules. Reactions that required hours to run completely in a conventional method can now be carried out within minutes. Thus, the application of microwave (MW) radiation in organic synthesis has become more promising considerable amount in resource-friendly and eco-friendly processes. The technique of microwaveassisted organic synthesis (MAOS) has successfully been employed in various material syntheses, such as transition metal-catalyzed cross-coupling, dipolar cycloaddition reaction, biomolecule synthesis, polymer formation, and the nanoparticle synthesis. The application of the microwave-technique in carbon-carbon and carbon-heteroatom bond formations via MCRs with major reported literature examples are discussed in this review.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Yang, Zhen-Zhen, Liang-Nian He, Jiao Gao, An-Hua Liu und Bing Yu. „Carbon dioxide utilization with C–N bond formation: carbon dioxide capture and subsequent conversion“. Energy & Environmental Science 5, Nr. 5 (2012): 6602. http://dx.doi.org/10.1039/c2ee02774g.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

Currie, Lucy, Luca Rocchigiani, David L. Hughes und Manfred Bochmann. „Carbon–sulfur bond formation by reductive elimination of gold(iii) thiolates“. Dalton Transactions 47, Nr. 18 (2018): 6333–43. http://dx.doi.org/10.1039/c8dt00906f.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Ni, Jing, und Xi Ping Hao. „Carbon Nitride Films Prepared by PECVD in CH₄-NH₃ Precursor“. Advanced Materials Research 538-541 (Juni 2012): 124–27. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.124.

Der volle Inhalt der Quelle

Annotation:

Carbon nitride (CNx) films were fabricated by plasma enhanced chemical vapor deposition technology in methane-ammonia system, in which the plasma was excited by the hollow cathode glow discharge. The composition，microstructure and hardness of the deposited films were investigated by measurements employing X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and nano-indentation experiment. The results indicate that the nitrogen content in the film varies from 4.2 to 8.6 at.% and the nitrogen atoms are bonded to carbon atoms through C-N, C=N and C≡N bonds. Furthmore, higher nitrogen content is in favor of the formation of C-N bond, which may enhance the film hardness.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Mehr Quellen

Dissertationen zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

Chakraborty, Rakesh Ranjan. „Explorative studies on carbon-nitrogen (C-N) bond formation and synthesis of nitrogen containing heterocyclic compounds“. Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2798.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Dabb, Serin Lloyd Chemistry Faculty of Science UNSW. „Hydrazine in late transition metal-mediated N-C bond formation“. Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/41428.

Der volle Inhalt der Quelle

Annotation:

This thesis describes investigations into the metal-mediated formation of nitrogen-carbon bonds from hydrazines and alkynes. Rh, Ir, Ru and Os metal complexes containing bidentate P,N- and N,N-donor ligands were all studied during the course of this work. A series of stereoisomers of metal complexes of general formula MCl2(PyP)2 (where M = Ru and Os, PyP = 1-(2-(diphenylphosphino)ethyl)pyrazole) (2.01-2.05) were synthesised. The isomerisation process of complexes 2.01-2.05 in solution was investigated. The ruthenium complex RuCl2(CO)(1-P-PyP)(2-P,N-PyP) (2.14), which contains one pendant PyP ligand bound through the P-donor ligand was synthesised, confirming the potential hemilability of the mixed P,N-donor ligand PyP. Chloride abstraction from the ruthenium complex trans,cis,cis-RuCl2(PyP)2 (2.01) was achieved using either a sodium or silver salt to yield the dimeric complexes of general formula [Ru(μ-Cl)(PyP)2]2[X]2 (where M = Ru, X = OSO2CF3 (2.06), BF4 (2.07), BPh4 (2.08), and BArF 2.09). [Os(μ-Cl)(PyP)2]2[BPh4]2 (2.10) was synthesised from sodium tetraphenylborate and trans,cis,cis-OsCl2(PyP)2 (2.04). The reactivity of dimeric complexes 2.06 and 2.08 towards substituted hydrazines was investigated. The methylhydrazine complex [Ru(PyP)2(NH2NHMe)][Cl][BPh4] (3.12) was synthesised. The methylhydrazine adduct of 3.12 binds to the metal centre in an end-on fashion via the NH2 group in solution, and in a bidentate fashion in the solid-state. This is the first reported example of a ruthenium complex containing a bidentate hydrazine ligand. The ruthenium-vinylidene complexes [RuCl(Me2PyP)2(=C=C(H)Ph)]BPh4 (4.15) and [RuCl(Me2PyP)2(=C=C(H)n-Bu)]BPh4 (4.16) (Me2PyP = 1-(2-(diphenylphosphino)ethyl)-3,5-dimethylpyrazole) were synthesised from trans,cis,cis-RuCl2(Me2PyP)2 (4.10) and the appropriate terminal alkyne. The reaction of alkynes with ruthenium complexes containing the PyP ligand was also investigated. Nitrogen-carbon bond formation was achieved through reaction of mono-substituted hydrazines with 4.06 and 4.07 to yield complexes of general formula [RuCl(1-P-Me2PyP)(2-P,N-Me2PyP)(2-N,C-(NH2N(R2)C(CH2R1)]BPh4 (where R1 = R2 = Ph (4.19), R1= Ph, R2 = Me (4.20), R1 = n-Bu, R2 = Ph, (4.21) or R1 = n-Bu, R2 = Me (4.22)). The mechanism of the formation of the stable metallocyclic complexes 4.19-4.22 was elucidated through studies of the reactivity of 4.15 towards a series of amines and hydrazines and relies on the labile nature of the N-donor of the P,N-donor ligand Me2PyP. A method for the synthesis of triflate complexes of rhodium Rh(PyP)(CO)(OSO2CF3) (5.13) and Rh(PyPhP)(CO)(OSO2CF3) (PyPhP = 1-(2-(diphenylphosphino)phenyl)pyrazole) (5.14) from rhodium chloride complexes was developed. The solid-state structure of rhodium triflate complex 5.14, which contained the more sterically rigid ligand PyPhP, exhibited a much greater distortion from the ideal square planar geometry than the rhodium analogue 5.13 which contains the PyP ligand. The triflate group of 5.13 and 5.14 was displaced by substituted hydrazines to yield new hydrazine complexes of rhodium. A series of Rh and Ir complexes with bidentate P,N- and N,N-donor ligands were found to catalyse the intermolecular hydroamination of alkynes with hydrazines. [Ir(bpm)(CO)2]BArF (6.08) was found to be the most efficient catalyst of those studies for this transformation, and was amongst the most efficient catalysts reported to date for this transformation. The influence of counter-ion was highly significant in the catalysed intermolecular hydroamination reaction. The substrate scope of the intermolecular hydroamination of alkynes with hydrazines was investigated using [Ir(bpm)(CO)2]BArF (6.08) as the catalyst.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Cai, Yingxiao. „Cobalt-catalyzed carbon-carbon bond formation by activation of carbon-halogen or carbon-hydrogen bonds“. Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX039/document.

Der volle Inhalt der Quelle

Annotation:

Ce travail de thèse présente le développement de nouvelles réactions de formation de liaisons carbone-carbone. Le premier chapitre décrit la cyanation d’arylzinciques par catalyse au cobalt à partir d’une source non toxique et bénigne, le N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS), et conduit à de bons rendements en benzonitriles correspondants. Dans cette réaction, le cobalt sert de catalyseur non seulement pour la formation des arylzinciques mais aussi pour la formation de liaisons C-CN. Les groupements fonctionnels, cétone et nitrile, sont permis lorsque le complexe de cobalt associé au ligand bipyridine est utilisé. Le deuxième chapitre porte sur l’homocouplage Csp3-Csp3. Un simple halogénure de cobalt permet de catalyser la dimérisation des halogénures d’alkyles et des acétates d’allyles avec de bons à d’excellents rendements. L’ajout d’iodure de sodium permet d’étendre cette réaction aux chlorures et tosylates d’alkyles. Le couplage croisé entre 2 halogénures d’alkyle différents a également été testé mais les conditions doivent être optimisées. Dans le troisième chapitre, le couplage croisé catalysé au cobalt entre des bromures vinyliques et des chlorures benzyliques est présenté. Des halogénures de vinyles et de benzyles porteurs de groupements electrodonneurs ou electroattrateurs peuvent ainsi être couplés efficacement avec rétention de la configuration de la double liaison. Un mécanisme radicalaire semble être impliqué. Enfin, le dernier chapitre décrit l’arylation d’une 2-phenylpyridine avec un arylzincique par catalyse au cobalt par activation d’une liaison C-H et conduit à de premiers résultats encourageants
This thesis presents the development of cobalt-catalyzed carbon-carbon bonds formation. The first chapter describes a novel cobalt-catalyzed electrophilic cyanation of arylzinc species, employing benign and non-toxic N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) as the cyano source. In this reaction, cobalt catalyzes both the formation of arylzinc species and the cyanation reaction. Various benzonitriles are synthesized affording good to excellent yields. Using cobalt-bipyridine complexes instead of CoBr2, ketone and nitrile groups can be tolerated. The second chapter reports cobalt-catalyzed Csp3-Csp3 homocoupling reaction. A simple catalytic system could deliver dimers of a number of alkyl halides/pseudohalides and allylic acetates. Sodium iodide is crucial for the homocoupling of unactivated alkyl chlorides and tosylates. This method is extended to alkyl-alkyl cross-coupling; however, the conditions still need to be optimized. The third chapter describes a cobalt-catalyzed vinyl-benzyl cross-coupling. A variety of functionalized vinyl bromides and benzyl chlorides are efficiently coupled under mild conditions in good to excellent yields, with retention of Z/E configuration. A few mechanistic experiments indicate a single electron transfer involved. The last chapter discusses the progress on the cobalt-catalyzed arylation of 2-phenylpyridine with an arylzinc species by C-H activation and promising results are obtained

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Ebe, Yusuke. „Iridium-Catalyzed Carbon-Carbon Bond Formation Reactions via C-H Bond Activation“. 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225417.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Arambasic, Milan. „Carbon-carbon bond formation via rhodium-catalysed C-S activation processes“. Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:e9e29a73-e637-4844-9a37-58b5ae4a3f99.

Der volle Inhalt der Quelle

Annotation:

In the following thesis, new methodologies towards harnessing C-S activation processes are documented. These methods utilise rhodium catalysis and are focused on the activation of aryl methyl sulfides. Chapter 1 provides an overview of the development of metal-catalysed C-S activation chemistry, with a focus on the catalytic systems, reagents and starting materials used to facilitate various C-C bond forming transformations. Chapter 2 describes a novel rhodium-catalysed cross-coupling reaction of aryl and alkyl terminal alkynes with simple aryl sulfides. This resulted in a Sonogashira-type transformation which exhibited orthogonality with traditional palladium catalysed Sonogashira chemistry. Chapter 3 documents a new catalytic system which allowed for the practical and efficient alkyne carbothiolation reactions of ketone-baring methyl sulfides. The carbothiolation products can be conveniently utilised in a one-pot three-component reaction to form highly substituted isoquinolines. Chapter 4 discusses the potential for future work. Chapter 5 presents the experimental data.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Sirokman, Gergely. „(N-heterocyclic-carbene)Copper(I)-catalyzed carbon-carbon bond formation using carbon dioxide“. Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39584.

Der volle Inhalt der Quelle

Annotation:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.
Vita.
Includes bibliographical references.
This thesis presents work towards the development of a new catalytic C-C bond forming reaction. Alkynes and olefins insert into [(IPr)CuH]2 (IPr = N,N-bis-(2,6-diisopropylphenyl)-1,3-imidazol-2-ylidene) to give copper vinyl and copper alkyl complexes. These copper complexes insert CO2 into the Cu-C bond to form copper acrylate and copper carboxylate complexes. Acrylic and carboxylic acids can be isolated by hydrolysis. A catalytic cycle based on (IPr)copper(I) was developed. Alkynes undergo reductive carboxylation to give acrylic acids in moderate yields. Unexpected interactions between several components of the catalytic system led to a number of side reaction, most importantly between [(IPr)CuH]2 and the product silyl acrylate. The use of silylcarbonate salts to desylilate the product enhanced yield. In addition, silylcarbonates can also serve as a source of CO2.
by Gergely Sirokman.
Ph.D.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Masuda, Yuusuke. „Development of New C-C Bond Forming Reactions Utilizing Light as Energy Source“. 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225634.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Heckler, James E. „Advances in gold-carbon bond formation: mono-, di-, and triaurated organometallics“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1441363597.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

Kunchithapatham, Kamala. „Development of Calcium and Palladium Catalysts for the Formation of Carbon-Carbon and Carbon-Heteroatom Bonds“. The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337955731.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Burgener, Simon [Verfasser], und Tobias Jürgen [Akademischer Betreuer] Erb. „Expanding the repertoire of enzymatic C-C bond formation with one-carbon units / Simon Burgener ; Betreuer: Tobias Jürgen Erb“. Marburg : Philipps-Universität Marburg, 2021. http://d-nb.info/1239239890/34.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Mehr Quellen

Bücher zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

C-X bond formation. Heidelberg: Springer, 2010.

Den vollen Inhalt der Quelle finden

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Vigalok, Arkadi. C-X Bond Formation. Springer, 2012.

Den vollen Inhalt der Quelle finden

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Taber, Douglass F., und Tristan Lambert. Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.001.0001.

Der volle Inhalt der Quelle

Annotation:

Organic Synthesis: State of the Art 2011-2013 is a convenient, concise reference that summarizes the most important current developments in organic synthesis, from functional group transformations to complex natural product synthesis. The fifth volume in the esteemed State of the Art series, the book compiles two years' worth of Douglass Taber's popular weekly column Organic Chemistry Highlights. The series is an invaluable resource, leading chemists quickly and easily to the most significant developments in the field. The book is logically divided into two sections: the first section focuses on specific topics in organic synthesis, such as C-N Ring Construction and Carbon-Carbon Bond Formation. Each topic is presented using the most significant publications within those areas of research. The journal references are included in the text. The second section focuses on benchmark total syntheses, with an analysis of the strategy for each, and discussions of pivotal transformations. Synthetic organic chemistry is a complex and rapidly growing field, with additional new journals appearing almost every year. Staying abreast of recent research is a daunting undertaking. This book is an ideal tool for both practicing chemists and students, offering a rich source of information and suggesting fruitful pathways for future investigation.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Buchteile zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

Wolfe, John P., Joshua D. Neukom und Duy H. Mai. „Synthesis of Saturated Five-Membered Nitrogen Heterocycles via Pd-Catalyzed CN Bond-Forming Reactions“. In Catalyzed Carbon-Heteroatom Bond Formation, 1–34. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633388.ch1.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Song, Qing-Wen, und Liang-Nian He. „Heterocyclic Synthesis Through C-N Bond Formation with Carbon Dioxide“. In Chemistry Beyond Chlorine, 435–53. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-30073-3_16.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Bichler, Paul, und Jennifer A. Love. „Organometallic Approaches to Carbon–Sulfur Bond Formation“. In C-X Bond Formation, 39–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12073-2_3.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Vigalok, Arkadi, und Ariela W. Kaspi. „Late Transition Metal-Mediated Formation of Carbon–Halogen Bonds“. In C-X Bond Formation, 19–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12073-2_2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Widenhoefer, Ross A., und Feijie Song. „Gold-Catalyzed Addition of Oxygen Nucleophiles to CC Multiple Bonds“. In Catalyzed Carbon-Heteroatom Bond Formation, 463–92. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633388.ch12.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Lebel, Hélène. „Rhodium-Catalyzed CH Aminations“. In Catalyzed Carbon-Heteroatom Bond Formation, 137–55. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633388.ch5.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Widenhoefer, Ross A., und Feijie Song. „Gold-Catalyzed Addition of Nitrogen and Sulfur Nucleophiles to CC Multiple Bonds“. In Catalyzed Carbon-Heteroatom Bond Formation, 437–61. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633388.ch11.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Yeung, Charles S., Peter K. Dornan und Vy M. Dong. „Transition Metal Catalyzed Approaches to Lactones Involving CO Bond Formation“. In Catalyzed Carbon-Heteroatom Bond Formation, 35–68. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527633388.ch2.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

Hoberg, Heinz. „Stoichiometric Reactions of C-C Bond Formation Promoted by Metal Systems“. In Carbon Dioxide as a Source of Carbon, 275–93. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3923-3_15.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Bae, Chulsung. „Catalytic Carbon–Boron Bond Formation via Activation of Alkane C–H Bonds“. In Catalysis by Metal Complexes, 73–111. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-90-481-3698-8_3.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Konferenzberichte zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

Sahu, Sunil, Anil Tyagi, Yonghwee Kim und Arjun Puri. „Accurate Identification of Gas-Bearing Formation in a Mature Field Using Pulsed Neutron Logs Prevented Well Abandonment“. In Gas & Oil Technology Showcase and Conference. SPE, 2023. http://dx.doi.org/10.2118/214153-ms.

Der volle Inhalt der Quelle

Annotation:

Abstract Operators typically update formation fluid saturation from producing wells as production impacts changes in formation fluid type and volume. An operator in India deployed a multi-detector pulsed neutron well logging tool on one of the old wells in a mature field to evaluate saturation profiles across multiple clastic formations. Production from the subject well had ceased due to water loading. The objective of the logging was to identify possible bypassed hydrocarbon zones before the operator decided on the well abandonment. A multi-detector pulsed neutron tool acquired a salinity-independent gas-sensitive time-based measurement from short-spaced and extra-long-spaced gamma-ray detectors. In addition, inelastic energy spectra-based carbon/oxygen (C/O) ratios were recorded to quantify formation oil saturation in a low water salinity environment. Another critical component in the saturation analysis workflow was the forward modeling of tool responses. We used the Monte Carlo N-particle (MCNP) stochastic method to predict gas-sensitive and C/O ratio responses in logging conditions. We had limited information on well conditions, such as cement bond condition and formation fluid properties, as no recent well logging was carried out to evaluate these. Thus, we performed saturation analyses in various conditions to reduce uncertainties in the results, including well-cemented, partially-cemented, and uncemented annulus conditions and different oil and gas densities. The analysis results identified one shallow sand unit containing gas. The sand was initially considered a water-dominant zone because the same zone produced water from adjacent wells. We evaluated the uncertainty in the gas saturation calculation attributed to cement bond quality and formation gas density. This helped to remove uncertainties in cement bond conditions and in-situ gas density on gas saturation. The identified sand unit was perforated and produced a large amount of gas. The accurate result of the gas saturation analysis saved the well from abandonment and increased reserves and production capacity. Additionally, the analysis revealed that water-filled formations were predominant in other sands. The C/O log analysis showed no bypassed oil in the lower sands. This paper further discusses case studies on candidate selection for pulsed neutron well logging, uncertainties in formation parameters, and the implications for saturation results.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

2

Ivanova, M. S., M. V. Vishnetskaya und K. O. Tomsky. „Kinetics of carbon dioxide absorption and C-C bond formation in media containing trifluoroacetic acid“. In ACTUAL PROBLEMS OF ORGANIC CHEMISTRY AND BIOTECHNOLOGY (OCBT2020): Proceedings of the International Scientific Conference. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0070381.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

3

Acquaviva, S., E. D’Anna, M. L. De Giorgi, G. Leggieri, A. Luches, M. Martino, A. Perrone und A. Zocco. „Carbon Nitride Films Synthesis and Deposition by Excimer Laser Ablation of Graphite Targets in Nitrogen Atmosphere“. In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cmf3.

Der volle Inhalt der Quelle

Annotation:

The prediction of a covalently bound carbon nitride solid β-C3N4 [1], with characteristics comparable to or even better than those of diamond, stimulated many attempts to synthesize and deposit thin carbon nitride films. In spite of almost a decade of search, this material has not yet been synthesized in stoichiometric phase. Nevertheless, it poses interesting issues about formation processes, C-N bonding states and CNx film properties. Ion/atomic beam assisted depositions are most frequently used. We are obtaining good results by using the simple technique of reactive laser ablation [2].

APA, Harvard, Vancouver, ISO und andere Zitierweisen

4

Akram, M. Zuhaib, Yangbo Deng, Muhammad Aziz, Bingquan Ge und Hao Jiang. „<bold>NH</bold> <sub> <bold>3</bold> </sub> <bold>Impact on Combustion and Emission Characteristics of N-Heptane Flame</bold>“. In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0329.

Der volle Inhalt der Quelle

Annotation:

<div class="section abstract"><div class="htmlview paragraph">Soot and carbon dioxide released from internal combustion engines became the key issues when using fossil fuels. The use of zero-carbon fuel, ammonia, with hydrocarbon fuels may play an important role in reducing the exhaust effect on the environment and mitigating the reliance on nonrenewable energy resources. However, ammonia reduces the flame speed of hydrocarbon fuels. A numerical approach was executed to study the ammonia impact on n-heptane, a diesel surrogate, flame. A kinetic mechanism was prepared by adding the sub-mechanism of ammonia, NO<sub>2</sub> and NO<sub>3</sub> emissions, and soot precursors to the n-heptane kinetic mechanism. The modified Arrhenius equation and soot surface reactions were used to study the soot formation with NOx emissions. The results showed that ammonia decreased the fractions of carbon-related species and raised the concentration of non-carbon-related species. Therefore, CO and CO<sub>2</sub> emission species reduced, whereas the fraction of non-emission species, H<sub>2</sub>O, increased at the end of combustion. From 0% to 50% addition of NH<sub>3</sub> in n-heptane fuel deteriorated about 36% soot and NO<sub>3</sub> emissions with only a 17% reduction in the laminar burning velocity. When the ammonia contents increased from 50% to 90%, the reduction in exhaust gas emissions and the burning velocity were around 57% and 37%, respectively. It is concluded by the current study that the dilution of ammonia in n-heptane fuel should be equal to or less than 50% because a higher reduction in CO, CO<sub>2</sub> and NO<sub>X</sub> emissions can be achieved with a small reduction in burning velocity.</div></div>

APA, Harvard, Vancouver, ISO und andere Zitierweisen

5

Bolotov, Vasiliy Alexandrovich, Serguei Fedorovich Tikhov, Konstantin Radikovich Valeev, Vladimir Timurovich Shamirzaev und Valentin Nikolaevich Parmon. „SELECTIVE FORMATION OF LINEAR ALPHA-OLEFINS VIA MICROWAVE CATALYTIC CRACKING OF LIQUID STRAIGHT-CHAIN ALKANES“. In Ampere 2019. Valencia: Universitat Politècnica de València, 2019. http://dx.doi.org/10.4995/ampere2019.2019.9894.

Der volle Inhalt der Quelle

Annotation:

Linear even-carbon-number alpha-olefins (LAO) with four or more carbon atoms are important compounds of high demand in chemical industry as precursors of a wide range of value-added chemicals [1]. LAO are used as co-monomers for polyethylene production, for the production of alcohols (mainly in detergents and plasticizers) and for synthesis of polyalphaolefins (used in synthetic lubricants). Alpha-olefins (C4, C6, C8 and C10) are mainly used to produce poly(vinyl chloride) plasticizers, high-density and linear low-density polyethylene to impart the stress-crack resistance. C10–C14 alpha-olefins can be used to synthesize linear alkylbenzene sulfonates (synthetic detergents). A conventional route to produce alpha-olefins is oligomerization of ethylene. The process provides production of high quality alpha-olefins but is very costly. If not oligomerization, LAO can be produced by thermal cracking of waxy paraffins but the product is not pure and contains numerous internal olefins, dienes and paraffin impurities. The process is conducted in the vapor phase at relatively low cracking temperatures and needs rapid quenching to prevent side reactions such as isomerization or cyclization. In our previous work [2], we showed that the selectivity to alpha-olefins can be increased considerably via catalytic cracking of n-alkanes under selective MW heating of catalysts. In the present work, the general regularities of MW cracking of n-alkanes are presented. Porous ceramic matrix Al2O3/Al composites (ceramometals) and various carbon materials (CM) having high dielectric losses were studied as supports of the catalysts. MW cracking was conducted with n-C16H34 and n-C28H58. The influence particle size and surface morphology of ceramometals and CM on the structural and group composition of the products was studied. It was established that LAO (C2-C23) and n-alkanes (C2-C26) were the main cracking products under selective MW heating of the used supports. The quantitative analysis of the products demonstrated that the liquid-phase process is more selective to alpha-olefins at the MW catalytic cracking than at the convectional thermal cracking. Silica modification of the surface of CM was shown to suppress spark discharge (usually observed at MW heating of CM); hence, the thermal cleavage of C-C bonds on the CM surface but not in the plasma discharge contributes the most to the formation of radicals. It was shown that the selectivity to liquid alpha-olefin could be more than 85 % under MW heating of cermets in region of the E - field node and decrease considerably in the region of H - field node.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

6

Narumanchi, Sreekant, Douglas DeVoto, Mark Mihalic, Tim Popp und Patrick McCluskey. „Thermal Performance and Reliability of Large-Area Bonded Interfaces in Power Electronics Packages“. In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65399.

Der volle Inhalt der Quelle

Annotation:

In automotive power electronics packages (e.g., insulated gate bipolar transistor [IGBT] packages), conventional polymeric thermal interface materials (TIMs) such as greases, gels, and phase-change materials pose a bottleneck to heat removal and are also associated with reliability concerns. High thermal performance bonded interfaces have become an industry trend. However, due to mismatches in the coefficient of thermal expansion between materials/layers and the resultant thermomechanical stresses, there could be voids and crack formations in these bonded interfaces as well as delaminations, which pose a problem from a reliability standpoint. These defects manifest themselves in increased thermal resistance in the package, which acts as a bottleneck to heat removal from the package. Hence, the objective of this research is to investigate and improve the thermal performance and reliability of novel bonded interface materials for power electronics packaging applications. Thermal performance and reliability of bonds/joints is presented for bonds based on a thermoplastic (polyamide) adhesive with embedded micron-sized carbon fibers, sintered silver (Ag), and conventional lead (Pb)-based solder materials. These materials form a bond between 50.8 mm × 50.8 mm footprint direct-bond-copper (DBC) substrate and copper (Cu) base plate samples. Samples undergo thermal cycling (−40°C to 150°C) for up to 2,000 cycles as an upper limit. Damage occurrence is monitored every 100 temperature cycles by several non-destructive techniques, including steady-state thermal resistance measurement, acoustic microscopy, and high-voltage potential testing. This yields a consistent story on the thermal performance and reliability of large-area joints under accelerated stress conditions.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

7

Kumar, Anand, und Anchu Ashok. „Catalytic Decomposition of Ethanol over Bimetallic Nico Catalysts for Carbon Nanotube Synthesis“. In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0039.

Der volle Inhalt der Quelle

Annotation:

In this work we investigate the use of NiCo bimetal/oxide as catalyst for hydrogen production from ethanol, with a focus on the deactivation pattern and the nature of the observed carbon deposition. It is well known that sintering and coke deposition during decomposition reaction significantly reduces the activity of the catalysts at higher temperature, by blocking the active sites of the catalysts. During ethanol decomposition reaction, the cleavage of C-C bond produces adsorbed *CH4 and *CO species that further decompose to form carbonaceous compounds. FTIR in-situ analysis was conducted between 50 to 400°C for all the catalysts to understand the reaction mechanism and product selectivity. Cobalt was found to be selective for aldehyde and acetate, whereas bimetallic Ni-Co was selective for the formation of CO at 400°C along with aldehyde. Complete conversion of ethanol was observed at 350°C and 420°C for NiCo and Cobalt respectively indicating an improvement in the rate of conversion when Ni was added to cobalt. The crystallinity, morphology and particle analysis of the used catalyst after reaction were studied using XRD, SEM and TEM respectively. The XRD shows the complete phase change of porous NiCoO2 to NiCo alloy and SEM indicates the presence of fibrous structure on the surface with 91.7 % of carbon while keeping 1:1 ratio of Ni and Co after the reaction. The detailed analysis of carbon structure using HRTEM-STEM shows the simultaneous growth of carbon nano fibers (CNFs) and multiwalled carbon nanotubes (MWCNTs) that were favored on larger and smaller crystallites respectively. Analysis of carbon formation on individual Co catalyst and bimetallic NiCo catalyst shows a clear difference in the initiation pattern of carbon deposition. Metallic Co nanoparticles were found to be more mobile where Co disperses along the catalysts surface, whereas NiCo nanoparticles were relatively less mobile, and maintained their structure.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

8

Aikman, Michael John Lundin. „Clean Energy from Oil: A Process to Generate Low Cost, Low Carbon Electricity from Mature and Depleted Oil Fields“. In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/210940-ms.

Der volle Inhalt der Quelle

Annotation:

ABSTRACT A novel process has been developed that targets the oil that remains in medium to heavy oil reservoirs (typically 80% or more of the original oil in place in Alberta and Saskatchewan amongst other regions) and efficiently extracts the energy in the chemical bonds of the oil to produce electricity. The produced CO2 is recovered for disposal so that it is not released into the atmosphere. The chemical bond energy in the oil is released by controlled in-situ combustion. Oxygen-enriched air is injected into the formation. The resulting combustion can result in formation temperatures in excess of 1800 °C. The heat is extracted to surface via a closed loop system of horizontal wells with circulating water as the carrier fluid. The produced water will have a surface temperature from 150 °C to over 250 °C which can generate electricity via a binary Organic Rankine Cycle ("ORC") turbine. The hot combustion product stream (a mixture of volatile oil, CO2, water vapour, nitrogen and other minor combustion products) is also used to produce electricity. The residual heat in the circulating water (which can have a temperature too low for electricity production) could be used for district heating or agriculture (greenhouses for year-round locally produced food crops). During the initial start-up of the operation, until the reservoir is sufficiently hot to produce stable electricity, any volatile oil that is produced is condensed and sold to market. Once the reservoir is sufficiently hot and there is stable production of electricity, the oil is reinjected back into the combustion zone as fuel for electricity production. The CO2 is recovered, either for use in EOR or disposal. The subsurface process has been modeled using a commercial petroleum reservoir simulator, STARS1. The design and performance of the surface equipment, including the turbines for electricity production (modeled as a binary ORC turbine system), has been based on industry performance empirical calculations. As the process targets medium to heavy oil reservoirs that have been developed for conventional oil production, the geologic risk is low. The drilling and completion cost is estimated to be less than C$20 million for a system that consists of 17 lateral circulation wells, 2 subsurface trunkline wells and two riser wells. The formation typically will be less than 1 km depth. A high residence time (which implies very long horizontal lateral length) is not required due to the high temperature gradient from the formation to the wellbore. The residence time of the water circulating in the lateral wells will be about 14.5 hours when the system is at plateau operation. The production riser completion has been designed to minimize heat losses to the overburden using insulation in the casing and a small riser residence time (about 0.2 hour). Economics have been based upon the fiscal regimes and prices in Alberta, Canada. Over C$850 million NPV(10% discount) results for a one-square mile development. With a Levelized Cost of Electricity equivalent (LCOEeq) as low as C$ 42 / MW-hr, the process is competitive with other sources of electricity. Patents are pending in the USA and Canada.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

9

Yang, Silin, Ahmed Raslan, Antoine Durocher, Felix Güthe und Jeffrey Bergthorson. „Numerical Investigation of NH3 Doped Fuels From Biomass Gasification on Fuel-Bound NOx Formation at Gas Turbine Conditions“. In ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/gt2023-103191.

Der volle Inhalt der Quelle

Annotation:

Abstract As our society transitioning away from fossil fuel-based energy system to reduce carbon emissions, renewable energy sources are needed to meet the increasing energy demand in the near future. Biomass, consisting mostly of plant-based organic materials, is a promising alternative to fossil fuels for carbon-neutral energy production. Unfortunately, during the gasification process, the nitrogen content in biomass is converted to NH3, which is then oxidized in the combustion process, leading to high NOx emissions through the fuel-NO pathway. The high NOx emissions from NH3 and NH3-containing fuels have prevented their implementation at scale. Depending on the gasification process, source of biomass, and combustion technology, the NH3 and water content can vary greatly. This works focuses on blends of 2% (mol) NH3 in CH4, diluted by up to 55% (mass) water. The combustion process is modelled by freeflame connected to a plug flow reactor (PFR), achieving a total residence time of 100 ms. Major chemistry involved in the fuel NO pathway were identified from reaction pathway analysis. NOx emissions were investigated under different equivalence ratios (Φ = 0.45–2.2) and inlet pressures (1 atm, 40 atm). NO concentration increases rapidly as NH3 is added to the fuel mixture, as expected. Under fuel rich conditions, NO decreases after the initial increase, and this reduction becomes more pronounced at elevated pressure and long residence times. At the same time, unburned NH3 and other reactive N species increase as NO decreases. The optimal conditions that minimize the total NOx and NH3 emissions were found to be slightly fuel rich, high pressure, and long residence time. Under these conditions, additional pathways involving NNH and N2O promotes the conversion of NH3 to N2. Large discrepancies among different thermochemical mechanisms highlight areas that still need to be researched. Results from the current study can assist in the modelling and design of low-emissions engines fuelled by biomass and NH3, thereby contributing to a carbon-neutral economy.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

10

Sabet, Seyed Morteza, Hassan Mahfuz, Andrew C. Terentis und Javad Hashemi. „A New Approach to the Synthesis of Carbon Nanotube-Polyhedral Oligomeric Silsesquioxane (POSS) Nanohybrids“. In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50925.

Der volle Inhalt der Quelle

Annotation:

To date, the functionalization of carbon nanotubes (CNTs) with Polyhedral Oligomeric Silsesquioxanes (POSS) has become one of the most intensively explored methods to produce CNT-based nanostructure composite materials. In this study, a simple and effective synthesizing method has been reported to prepare a nanohybrid material consisting of multi-walled carbon nanotubes (MWCNT) and aminopropylisobutyl-POSS. The approach is based on covalent bonding between CNTs and POSS molecules. Characterization of the as-received materials as well as the POSS-treated CNTs has been performed. Raman and Fourier transform infrared spectroscopic analyses verify the covalent grafting of POSS onto CNT walls through the formation of amide bonds. TEM studies reveal the attachment of relatively high amount of POSS to the CNT walls in POSS-treated product. TGA observations suggest that the presence of relatively high amount of POSS in MWCNT-POSS product is responsible for the thermal stability of CNTs at temperature range of RT–200 °C. The resulting nanohybrids with improved functionality and thermal stability would be good candidates as reinforcing materials for compatible polymer matrices.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Berichte der Organisationen zum Thema "Carbon-Nitrozen bond(C-N) formation"

1

Shomer, Ilan, Ruth E. Stark, Victor Gaba und James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7587238.bard.

Der volle Inhalt der Quelle

Annotation:

The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Wir bieten Rabatte auf alle Premium-Pläne für Autoren, deren Werke in thematische Literatursammlungen aufgenommen wurden. Kontaktieren Sie uns, um einen einzigartigen Promo-Code zu erhalten!