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Artykuły w czasopismach na temat "Pd-C core"
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Wang, Hong, Ying Wang, Xianyou Wang, Peiying He, Lanhua Yi, Wei Yi i Xue Liu. "Investigation of the Performance ofAucore-Pdshell/C as the Anode Catalyst of Direct Borohydride-Hydrogen Peroxide Fuel Cell". International Journal of Electrochemistry 2011 (2011): 1–7. http://dx.doi.org/10.4061/2011/129182.
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The carbon-supported bimetallic Au-Pd catalyst with core-shell structure is prepared by successive reduction method. The core-shell structure, surface morphology, and electrochemical performances of the catalysts are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption spectrometry, linear sweep voltammetry, and chronopotentiometry. The results show that the Au-Pd/C catalyst with core-shell structure exhibits much higher catalytic activity for the direct oxidation of NaBH4than pure Au/C catalyst. A direct borohydride-hydrogen peroxide fuel cell, in which the Au-Pd/C with core-shell structure is used as the anode catalyst and the Au/C as the cathode catalyst, shows as high as 68.215 mW cm−2power density.
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Dong, Nan, Ke Cao, Chen Xi Si i Dan Zheng. "Pd Doped Ag@C Core-Shell Nanocomposite for Electrochemical Sensitive Determination of Bisphenol A". Key Engineering Materials 905 (4.01.2022): 204–9. http://dx.doi.org/10.4028/www.scientific.net/kem.905.204.
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In this work, core–shell structured nanocomposites consisting of Pd doped Ag@C were synthesized by impregnation–reduction method. Then, sensing electrodes were fabricated by modifying Pd/Ag@C core-shell nanoparticles on screen-printed electrodes (SPE) for electrochemical determination of bisphenol A (BPA). The composition and morphology of nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, X ray diffraction and energy-dispersive X-ray spectroscopy. The electrochemical response characteristics of nanocomposites to BPA was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results indicated that, compared with Ag@C and Pd/C, Pd/Ag@C nanocomposite shows greater catalytic activity to the oxidation of BPA due to the synergistic effect of Pd and Ag. Among the four synthesized Pd/Ag@C-x (x=1-4) nanomaterials, the Pd/Ag@C-3 exhibits the best sensing performance toward the sensitive detection of BPA. The linear range for BPA determination was from 8.0×10-8 M to 1.5×10-5M with a detection limit of 1.0×10-8 M. A less than 9% oxidation peak current change was observed on the determination of BPA using Pd/Ag@C-3/SPE when added different interfering species into the BPA solution. The oxidation peak current attenuation of BPA on Pd/Ag@C-3/SPE within five weeks was found to be less than 3.6%.
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Chen, Cheng-Chuan, i Lin-Chi Chen. "Synthesis and characterization of Pd–Ni core–shell nanocatalysts for alkaline glucose electrooxidation". RSC Advances 5, nr 66 (2015): 53333–39. http://dx.doi.org/10.1039/c5ra06331k.
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Pdshell–Nicore electrocatalyst decorated carboxylated multi-walled carbon nanotubes (Pd–Ni/C) are synthesized using a two-stage polyol method. Pd–Ni/C (1 : 0.06) provides the highest glucose electrocatalytic oxidation current density.
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Zhao, Yuewu, Huile Jin, Huan Zhou, Juanjuan Lin, Shun Wang i Jichang Wang. "Fabrication of Te@Pd Core–Shell Hybrids for Efficient C–C Coupling Reactions". Journal of Physical Chemistry C 116, nr 13 (23.03.2012): 7416–20. http://dx.doi.org/10.1021/jp212197r.
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Gao, Fei, Yangping Zhang, Huaming You, Zhuolin Li, Bin Zou i Yukou Du. "One-pot synthesis of core@shell PdAuPt nanodendrite@Pd nanosheets for boosted visible light-driven methanol electrooxidation". Chemical Communications 57, nr 97 (2021): 13198–201. http://dx.doi.org/10.1039/d1cc06059g.
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We developed a simple method to obtain the PdPtAu@Pd core@shell catalyst for methanol oxidation reaction. The PdPtAu@Pd exhibited superior photo-electrocatalytic behaviors, whose mass activity is 2.3 and 6.7 times higher than Pt/C and Pd/C.
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Jiang, Baojiang, Sanzhao Song, Jianqiang Wang, Ying Xie, Wenyi Chu, Hongfeng Li, Hui Xu, Chungui Tian i Honggang Fu. "Nitrogen-doped graphene supported Pd@PdO core-shell clusters for C-C coupling reactions". Nano Research 7, nr 9 (17.07.2014): 1280–90. http://dx.doi.org/10.1007/s12274-014-0492-1.
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Tessier, Béatrice C., Andrea E. Russell, Brian R. Theobald i David Thompsett. "PtML/Pd/C Core-Shell Electrocatalysts for the ORR in PEMFCs". ECS Transactions 16, nr 37 (18.12.2019): 1–11. http://dx.doi.org/10.1149/1.3106718.
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Petrov, Sergey A., Dina V. Dudina, Arina V. Ukhina i Boris B. Bokhonov. "Morphological and Structural Transformations of Fe-Pd Powder Alloys Formed by Galvanic Replacement, Annealing and Acid Treatment". Materials 15, nr 10 (17.05.2022): 3571. http://dx.doi.org/10.3390/ma15103571.
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In this article, we report the preparation and structural features of Fe-Pd powder alloys formed by galvanic replacement, annealing and selective dissolution of iron via acid treatment. The alloys were studied by the X-ray diffraction phase analysis, Mössbauer spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy. The Fe@Pd core–shell particles were obtained by a galvanic replacement reaction occurring upon treatment of a body-centered cubic (bcc) iron powder by a solution containing PdCl42− ions. It was found that the shells are a face-centered cubic (fcc) Pd(Fe) solid solution. HCl acid treatment of the Fe@Pd core–shell particles resulted in the formation of hollow Pd-based particles, as the bcc phase was selectively dissolved from the cores. Annealing of the Fe@Pd core–shell particles at 800 °C led to the formation of fcc Fe-Pd solid solution. Acid treatment of the Fe-Pd alloys formed by annealing of the core–shell particles allowed selectively dissolving iron from the bcc Fe-based phase (Fe(Pd) solid solution), while the fcc Fe-rich Fe-Pd solid solution remained stable (resistant to acid corrosion). It was demonstrated that the phase composition and the Fe/Pd ratio in the alloys (phases) can be tailored by applying annealing and/or acid treatment to the as-synthesized Fe@Pd core–shell particles.
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Albers, Peter W., Konrad Möbus, Stefan D. Wieland i Stewart F. Parker. "The fine structure of Pearlman's catalyst". Physical Chemistry Chemical Physics 17, nr 7 (2015): 5274–78. http://dx.doi.org/10.1039/c4cp05681g.
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Boltersdorf, Jonathan, Asher C. Leff, Gregory T. Forcherio i David R. Baker. "Plasmonic Au–Pd Bimetallic Nanocatalysts for Hot-Carrier-Enhanced Photocatalytic and Electrochemical Ethanol Oxidation". Crystals 11, nr 3 (25.02.2021): 226. http://dx.doi.org/10.3390/cryst11030226.
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Gold–palladium (Au–Pd) bimetallic nanostructures with engineered plasmon-enhanced activity sustainably drive energy-intensive chemical reactions at low temperatures with solar simulated light. A series of alloy and core–shell Au–Pd nanoparticles (NPs) were prepared to synergistically couple plasmonic (Au) and catalytic (Pd) metals to tailor their optical and catalytic properties. Metal-based catalysts supporting a localized surface plasmon resonance (SPR) can enhance energy-intensive chemical reactions via augmented carrier generation/separation and photothermal conversion. Titania-supported Au–Pd bimetallic (i) alloys and (ii) core–shell NPs initiated the ethanol (EtOH) oxidation reaction under solar-simulated irradiation, with emphasis toward driving carbon–carbon (C–C) bond cleavage at low temperatures. Plasmon-assisted complete oxidation of EtOH to CO2, as well as intermediary acetaldehyde, was examined by monitoring the yield of gaseous products from suspended particle photocatalysis. Photocatalytic, electrochemical, and photoelectrochemical (PEC) results are correlated with Au–Pd composition and homogeneity to maintain SPR-induced charge separation and mitigate the carbon monoxide poisoning effects on Pd. Photogenerated holes drive the photo-oxidation of EtOH primarily on the Au-Pd bimetallic nanocatalysts and photothermal effects improve intermediate desorption from the catalyst surface, providing a method to selectively cleave C–C bonds.
Rozprawy doktorskie na temat "Pd-C core"
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King, Billy Ellis. "T-cell Dysfunction by HCV Core Protein Involves PD-1/PD-L1 Signaling". Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etd/2082.
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In 1989 the hepatitis C virus was identified as a significant cause of post-transfusion hepatitis. Nearly two decades later there is still no vaccine, inadequate treatment options, and limited understanding of how the virus establishes chronicity in the majority of the people it infects. Recent reports suggest that the interaction of a negative co-stimulatory pathway mediated by PD-1 and PDL-1 is associated with persistent viral infection. The role, if any, that PD-1/PDL-1 has in HCV infection is unknown. In this study we report that PD-1 is upregulated in T-cells from persons with chronic HCV infection when compared to healthy donors. In addition, PD-1 and PDL-1 are upregulated on T-cells from healthy donors when exposed to extracellular HCV core protein (a nucleocapsid protein that is immunosuppressive); upregulation of PD-1 is mediated by core's ability to bind to the complement receptor gC1q. We also report that the observed T-cell function can be restored by blocking the PD-1/PDL-1 interaction. Our results indicate that HCV core can upregulate an important negative T-cell signaling pathway that is associated with viral persistence. This upregulation of PD-1/PDL-1 represents a novel and perhaps shared mechanism that viral pathogens may use to subvert the human immune response. It also represents a potential new treatment option for the millions of people who suffer from chronic hepatitis C infection.
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Singh, Vinod. "Gas phase synthesis of size selected Pd and Pd-C core - shell nanoparticles for hydrogen sensing application". Thesis, 2018. http://eprint.iitd.ac.in:80//handle/2074/7963.
Pełny tekst źródłaCzęści książek na temat "Pd-C core"
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Taber, Douglass. "C-O Ring Natural Products: (-)-Serotobenine (Fukuyama-Kan), (-)-Aureonitol (Cox), Salmochelin SX (Gagné), Botcinin F (Shiina), (-)-Saliniketal B (Paterson), Haterumalide NA (Borhan)". W Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0051.
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Tohru Fukuyama of the University of Tokyo and Toshiyuki Kan of the University of Shizuoka devised ( J. Am. Chem. Soc. 2008, 130, 16854) the chiral auxiliary-directed Rh-mediated cyclization of 1, setting the two stereogenic centers of 2 with high stereocontrol. The ester 2 was carried on to the indole alkaloid (-)-Serotobenine 3. In the course of a synthesis of (-)-Aureonitol 6, Liam R. Cox of the University of Birmingham developed (J. Org. Chem. 2008, 73, 7616) the diastereoselective intramolecular addition of an allyl silane 4 to give the tetrahydrofuran 5. In analogy to what is known about the intramolecular ene reaction, the diastereocontrol observed for this cyclization may depend on the allyl silane being Z. Michel R. Gagné of the University of North Carolina found (J. Am. Chem. Soc. 2008, 130, 12177) that the Ni-catalyzed coupling of organozinc halides could be extended to glycosyl halides such as 7. This opened ready access to C -alkyl and C -aryl glycosides, including Salmochelin SX 10. Isamu Shiina of the Tokyo University of Science established (Organic Lett. 2008, 10, 3153) that the acid-mediated cyclization of the Sharpless-derived epoxide 10 proceeded with clean inversion, to give 11. The highly-substituted tetrahydropyran core 11 was then elaborated to the antifungal Botcinin F 12. Ian Paterson of Cambridge University optimized (Organic Lett. 2008, 10, 3295) the Pd-catalyzed spirocyclization of the ene diol 13, leading to 14, the enantiomerically-pure bicyclic core of (-)-Saliniketal B 15. Haterumalide NA 18 presented the particular challenge of assembling the geometrically-defined chloroalkene, in addition to closing the macrolide ring. Babak Borhan of Michigan State University addressed (J. Am. Chem. Soc. 2008, 130, 12228) both of these challenges together, electing to employ a chlorovinylidene chromium carbenoid, as developed by Falck and Mioskowski, to effect the macrocyclization of 16 to 17.
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Taber, Douglass F. "C-H Functionalization: The Chen Synthesis of Celogentin C". W Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0019.
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Christian R. Goldsmith of Auburn University developed (Synlett 2010, 1377) a method for radical chlorination of 1 using commercial peracetic acid. Noritaka Mizuno of the University of Tokyo devised (Nat. Chem. 2010, 2, 478) a bulky polyoxometalate that mediated the selective hydroxylation of the secondary C-H bonds of 3. Christina White of the University of Illinois showed (Science 2010, 327, 566) that Fe-mediated C-H oxidation is sensitive to the expected electronic effects, so that 5 was selectively oxidized to 6. Irena S. Akhrem of the A. N. Nesmeyanov Institute of Organoelement Compounds established (Tetrahedron Lett. 2010, 51, 259) that a C-H bond of 7 could be efficiently converted to a C-C bond. Melanie S. Sanford of the University of Michigan extended (Organic Lett. 2010, 12, 532) directed palladation to 9, effecting selective acetoxylation of the methyl group. Herman O. Sintim of the University of Maryland observed (Angew. Chem. Int. Ed. 2010, 49, 3964) that the O-linked diazoamide 11 selectively cyclized to 12. The corresponding C-linked diazoamide gave only five-membered ring formation. Yasushi Obora and Yasutaka Ishii of Kansai University devised (Organic Lett. 2010, 12, 1372) conditions for the selective allylic amination of 13. Marvin J. Miller of the University of Notre Dame developed (Tetrahedron Lett. 2010, 51, 328) the nitrosoisoxazole 16 for the allylic amination of 15. David A. Powell of Merck Frosst established (J. Org. Chem. 2010, 75, 2726) a protocol for the selective amination of the aromatic methyl group of 18. Ying-Yeung Yeung of the National University of Singapore effected (Organic Lett. 2010, 12, 2128) selective allylic oxidation of 21 with a hypervalent iodine reagent. Gullapalli Kumaraswamy of the Indian Institute of Chemical Technology, Hyderabad, allylated (J. Org. Chem. 2010, 75, 3916) an amine 23 using commercial aqueous t -BuOOH. Corey R. J. Stephenson of Boston University used (J. Am. Chem. Soc. 2010, 132, 1464) visible light to activate 26 for homologation to 27. In the course of a synthesis of the bicyclic nonribosomal peptide celogentin C, isolated from the seeds of the plumed cockscomb Celosia argentea, Gong Chen of Pennsylvania State University took advantage (Angew. Chem. Int. Ed. 2010, 49, 958) of Pd activation to effect specific coupling of the iodoindole 29 with the leucine derivative 28. On a 4-gram scale, this coupling proceeded in 85% yield.
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Taber, Douglass F. "Construction of Alkylated Stereogenic Centers". W Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0041.
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Andreas Pfaltz of the University of Basel and Keisuke Suzuki of the Tokyo Institute of Technology showed (Angew. Chem. Int. Ed. 2010, 49, 881) that the iodohydrin of 1 did not interfere with the enantioselective hydrogenation. J. R. Falck of UT Southwestern developed (J. Am. Chem. Soc. 2010, 132, 2424) a procedure for coupling arene boronic acids with a cyano triflate 3, readily available in high ee from the corresponding aldehyde. Anita R. Maguire of University College Cork devised (J. Am. Chem. Soc. 2010, 132, 1184) a Cu catalyst for the enantioselective C-H insertion cyclization of 5 to 6. Jin-Quan Yu of Scripps/La Jolla established (J. Am. Chem. Soc. 2010, 132, 460) a complementary enantioselective C-H functionalization protocol, converting the prochiral 7 into 8 in high ee. Xumu Zhang of Rutgers University effected (Angew. Chem. Int. Ed. 2010, 49, 4047) enantioselective branching hydroformylation of 9 to give 10. T. V. RajanBabu of Ohio State University established (J. Am. Chem. Soc. 2010, 132, 3295) the enantioselective hydrovinylation of a diene 11 to the diene 12. Gregory C. Fu extended (J. Am. Chem. Soc. 2010, 132, 1264, 5010) Ni-mediated cross-coupling, both with alkenyl and aryl nucleophiles, to the racemic bromoketone 13. Hyeung-geun Park and Sang-sup Jew of Seoul National University used (Organic Lett. 2010, 12 , 2826) their asymmetric phase transfer protocol to effect the enantioselective alkylation of the amide 15. Kyung Woon Jung of the University of Southern California showed (J. Org. Chem. 2010, 75, 95) that the oxidative Pd-mediated Heck coupling of arene boronic acids to 17 could be effected in high ee. Nicolai Cramer of ETH Zurich observed (J. Am. Chem. Soc. 2010, 132, 5340) high enantioinduction in the cleavage of the prochiral cyclobutanol 19. Alexandre Alexakis of the University of Geneva achieved (Organic Lett. 2010, 12, 1988) the long-sought goal of efficient enantioselective conjugate addition of a Grignard reagent to an unsaturated aldehyde 21. Professor Alexakis also established (Organic Lett. 2010, 12, 2770) conditions for enantioselective conjugate addition to a nitrodiene 23. This procedure worked equally well for β-alkynyl nitroalkenes.
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Taber, Douglass F. "Flow Chemistry: The Direct Production of Drug Metabolites". W Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0016.
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Several overviews of flow chemistry appeared recently. Katherine S. Elvira and Andrew J. deMello of ETH Zürich wrote (Nature Chem. 2013, 5, 905) on microfluidic reactor technology. D. Tyler McQuade of Florida State University and the Max Planck Institute Mühlenberg reviewed (J. Org. Chem. 2013, 78, 6384) applications and equipment. Jun-ichi Yoshida of Kyoto University focused (Chem. Commun. 2013, 49, 9896) on transformations that cannot be effected under batch conditions. Detlev Belder of the Universität Leipzig reported (Chem. Commun. 2013, 49, 11644) flow reactions coupled to subsequent micropreparative separations. Leroy Cronin of the University of Glasgow described (Chem. Sci. 2013, 4, 3099) combining 3D printing of an apparatus and liquid handling for convenient chemical synthesis and purification. Many of the reactions of organic synthesis have now been adapted to flow conditions. We will highlight those transformations that incorporate particularly useful features. One of those is convenient handling of gaseous reagents. C. Oliver Kappe of the Karl-Franzens-University Graz generated (Angew. Chem. Int. Ed. 2013, 52, 10241) diimide in situ to reduce 1 to 2. David J. Cole-Hamilton immobilized (Angew. Chem. Int. Ed. 2013, 52, 9805) Ru DuPHOS on a heteropoly acid support, allowing the flow hydrogenation of neat 3 to 4 in high ee. Steven V. Ley of the University of Cambridge added (Org. Process Res. Dev. 2013, 17, 1183) ammonia to 5 to give the thiourea 6. Alain Favre-Réguillon of the Conservatoire National des Arts et Métiers used (Org. Lett. 2013, 15, 5978) oxygen to directly oxidize the aldehyde 7 to the carboxylic acid 8. Professor Kappe showed (J. Org. Chem. 2013, 78, 10567) that supercritical acetonitrile directly converted an acid 9 to the nitrile 10. Hisao Yoshida of Nagoya University added (Chem. Commun. 2013, 49, 3793) acetonitrile to nitrobenzene 11 to give the para isomer 12 with high regioselectively. Kristin E. Price of Pfizer Groton coupled (Org. Lett. 2013, 15, 4342) 13 to 14 to give 15 with very low loading of the Pd catalyst. Andrew Livingston of Imperial College demonstrated (Org. Process Res. Dev. 2013, 17, 967) the utility of nanofiltration under flow conditions to minimize Pd levels in a Heck product.
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Taber, Douglass F. "Organic Functional Group Transformation". W Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0007.
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Susumu Saito of Nagoya University developed (Angew. Chem. Int. Ed. 2011, 50, 3006) Fe-catalyzed conditions, compatible with alkenes, for converting an alcohol 1 to the amine 2. Corey R. J. Stephenson of Boston University took advantage (Nature Chem. 2011, 3, 140) of photoredox catalysis to convert an alcohol 3 to the iodide 4. Jing-Mei Huang of the South China University of Technology condensed (J. Org. Chem. 2011, 76, 3511) the halide 5 with benzaldehyde and aqueous ammonia to give the imine 6. Young Hoon Jung of Sungkyunkwan University used (Tetrahedron Lett. 2011, 52, 1901) chlorosulfonyl isocyanate to convert a benzylic (or allylic) ether 7 into the urethane 8. David Crich of Centre de Recherche de Gif coupled (Org. Lett. 2011, 13, 2256) the isocyanate 9 with the acid 10 to give the amide 11. Tobias Ritter of Harvard University effected (J. Am. Chem. Soc. 2011, 133, 1760) α-hydroxylation of the acidic ketone 12 by exposure to O2 in the presence of a Pd catalyst. Gowravaram Sabitha of the Indian Institute of Chemical Technology, Hyderabad, activated (Org. Lett. 2011, 13, 382) Pd(OH)2 by exposure to H2 , then used the activated catalyst to isomerize the allylic alcohol 14 to the aldehyde 15 . Richard C. Hartley of the University of Glasgow combined (Tetrahedron Lett. 2011, 52, 3020) commercial Nysted reagent and Cp2 TiCl2 to methyl-enate the ester 16. The enol ether 17 is a versatile intermediate, giving, inter alia, the methyl ketone by hydrolysis, or the α-hydroxy ketone on exposure to peracid. The activation of alkynes continues to be an area of vigorous investigation. Lukas Hintermann of the Technische Universitä t München devised (J. Am. Chem. Soc. 2011, 133, 8138) a Ru catalyst for the hydration of 18 to the aldehyde 19. Issa Yavari of Tarbiat Modares University effected (Tetrahedron Lett. 2011, 52, 668) oxidation of 20 to the N-sulfonyl amidine 22. Craig A. Merlic of UCLA coupled (Org. Lett. 2011, 13, 2778) 24 with the vinyl boronate derived from 23 to give the silyl enol ether 25. Li-Biao Han of AIST Tsukuba prepared (Chem. Commun. 2011, 47, 2333) 28 by adding 27 to 26.
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Taber, Douglass. "New Methods for the Stereoselective Construction of N-Containing Rings". W Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0053.
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Several methods have been reported for the stereocontrolled preparation of pyrrolidine and piperidine derivatives. Alison J. Frontier of the University of Rochester has observed (Organic Lett. 2007, 9, 4939) that hydrogenation of acyl pyrroles such as 1 gave good control not just around the ring, but also on the sidechain. Chi-Ming Che of the University of Hong Kong has devised ( J. Am. Chem. Soc. 2007, 129, 5828) a catalyst that converted amides such as 3 into the cyclized product 4, also with high diastereocontrol. Jean Ollivier of the Université de Paris-Sud, following the Sato procedure, has applied (Tetrahedron Lett. 2007, 48, 8765) the Kulinkovich reaction to allylated amino acid esters such as 5 , to give, after Fe-mediated fragmentation, the enantiomerically-pure piperidone 7 . Richard C. Hartley of the University of Glasgow has reported (J. Org. Chem. 2007, 72, 10287) what are, remarkably, the first examples of the aza-Petasis-Ferrier reaction, converting an ester such as 9, by carbonyl methylenation followed by Mannich cyclization, into the piperidone 10. Procedures for catalytic enantioselective C-N ring construction have also been developed. Armando Córdova of Stockholm University has shown (Tetrahedron Lett . 2007, 48, 8695) that condensation of 11 with 12 led to 14, which on reduction and hydrolysis delivered the 3-aryl proline 15. In an even simpler case, Santos Fustero of the Universidad de Valencia found (Organic Lett. 2007, 9, 5283) that the aldehyde 16 could cyclize to 17 with high ee. In a different approach (J. Am. Chem. Soc. 2007, 129, 14811), William E. Greenberg and Chi-Huey Wong of Scripps/La Jolla harnessed the power of an enzyme to mediate the addition of 19 to 18, leading to the pyrrolidine 21 . Daniel P. Furkert of the University of Bath has applied (Organic Lett. 2007, 9, 3769) the powerful Itsuno-Corey reduction to the piperidone 22, leading, after SN2’ displacement, to the alkene 23. To construct larger rings, Barry M. Trost of Stanford University has employed (Angew. Chem. Int. Ed. 2007, 46, 6123) his powerful Pd catalyst to effect opening of the racemic aziridine 24, leading, after metathesis, to the amine 27.
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Taber, Douglass F. "New Methods for Carbocyclic Construction: The Kim Synthesis of Pentalenene". W Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0080.
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Daesung Lee of the University of Illinois, Chicago, taking advantage of the facile insertion of an alkylidene carbene into a C-Si bond, established (J. Am. Chem. Soc. 2010, 132, 6640) a general method for the conversion of an α-silyl ketone 1 into the silyl cyclopropene 3. Christopher D. Bray of Queen Mary University showed (J. Org. Chem. 2010, 75, 4652) that the sulfonyl phosphonate 5 converted the enantiomerically pure epoxide 4 into the cyclopropane 6. Paul Margaretha of the University of Hamburg observed (Organic Lett. 2010, 12, 728) smooth photochemical combination of 7 and 8 to give 9 with high diastereocontrol. Tõnis Kanger of the Tallinn University of Technology devised (Organic Lett. 2010, 12, 2230) the three-component coupling of 10, 11, and diethyl amine to give, after reduction, the highly substituted cyclobutane 12. Min Shi of the Shanghai Institute of Organic Chemistry uncovered (J. Org. Chem. 2010, 75, 902) an interesting new thermal rearrangement: the conversion of 13 to 14. José G. Ávila-Zárraga of the Universidad Nacional Autónoma de México applied (Tetrahedron Lett. 2010, 51, 2232) Pd catalysis to the cyclization of the epoxy nitrile 15, redirecting the reaction from the expected cyclobutane to the cyclopentanol 16. Ullrich Jahn of the Academy of Sciences of the Czech Republic effected (J. Org. Chem. 2010, 75, 4480) the oxidative radical cyclization of 17 to 18. Initial deprotonation of the substrate with t -BuMgCl switched the product to the trans diastereomer. Jonathan W. Burton of the University of Oxford employed (Organic Lett. 2010, 12, 2738) a related oxidative cyclization for the diastereoselective conversion of 19 to 20. E. J. Corey of Harvard University reported (Organic Lett. 2010, 12, 300) a new ligand for the enantioselective Ni-mediated reduction of 21 to 22. Shu-Li You, also of the Shanghai Institute of Organic Chemistry, established (J. Am. Chem. Soc. 2010, 132, 4056) that the alcohol 23, readily prepared by oxidation of p -cresol, could be cyclized to the crystalline 25 in high ee.
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Lambert, Tristan H. "Flow Chemistry". W Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0017.
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Timothy F. Jamison at MIT developed (Org. Lett. 2013, 15, 710) a metal-free continuous-flow hydrogenation of alkene 1 using the protected hydroxylamine reagent 2 in the presence of free hydroxylamine. The reduction of nitroindole 4 to the corresponding aniline 5 using in situ-generated iron oxide nanocrystals in continuous flow was reported (Angew. Chem. Int. Ed. 2012, 51, 10190) by C. Oliver Kappe at the University of Graz. A flow method for the MPV reduction of ketone 6 to alcohol 7 was disclosed (Org. Lett. 2013, 15, 2278) by Steven V. Ley at the University of Cambridge. Corey R.J. Stephenson, now at the University of Michigan, developed (Chem. Commun. 2013, 49, 4352) a flow deoxygenation of alcohol 8 to yield 9 using visible light photoredox catalysis. Stephen L. Buchwald at MIT demonstrated (J. Am. Chem. Soc. 2012, 134, 12466) that arylated acetaldehyde 11 could be generated from aminopyridine 10 by diazonium formation and subsequent Meerwein arylation of ethyl vinyl ether in flow. The team of Takahide Fukuyama and Ilhyong Ryu at Osaka Prefecture University showed (Org. Lett. 2013, 15, 2794) that p-iodoanisole (12) could be converted to amide 13 via low-pressure carbonylation using carbon monoxide generated from mixing formic and sulfuric acids. The continuous-flow Sonogashira coupling of alkyne 14 to produce 15 using a Pd-Cu dual reactor was developed (Org. Lett. 2013, 15, 65) by Chi-Lik Ken Lee at Singapore Polytechnic. A tandem Sonogashira/cycloisomerization procedure to convert bromopyridine 16 to aminoindolizine 18 in flow was realized (Adv. Synth. Cat. 2012, 354, 2373) by Keith James at Scripps, La Jolla. A procedure for the Pauson-Khand reaction of alkene 19 to produce the bicycle 20 in a photochemical microreactor was reported (Org. Lett. 2013, 15, 2398) by Jun-ichi Yoshida at Kyoto University. Kevin I. Booker-Milburn at the University of Bristol discovered (Angew. Chem. Int. Ed. 2013, 52, 1499) that irradiation of N-butenylpyrrole 21 in flow produced the rearranged tricycle 22. Professor Jamison described (Angew. Chem. Int. Ed. 2013, 52, 4251) a unique peptide coupling involving the photochemical rearrangement of nitrone 23 to the hindered dipeptide 24 in continuous flow.
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Lambert, Tristan H. "Synthesis and Reactions of Alkenes". W Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0032.
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Christine L. Willis and Varinder K. Aggarwal at the University of Bristol have developed (Angew. Chem. Int. Ed. 2012, 51, 12444) a procedure for the diastereodivergent synthesis of trisubstituted alkenes via the protodeboronation of allylic boronates, such as in the conversion of 1 to either 2 or 3. An alternative approach to the stereoselective synthesis of trisubstituted alkenes involving the reduction of the allylic C–O bond of cyclic allylic ethers (e.g., 4 to 5) was reported (Chem. Commun. 2012, 48, 7844) by Jon T. Njardarson at the University of Arizona. A novel synthesis of allylamines was developed (J. Am. Chem. Soc. 2012, 134, 20613) by Hanmin Huang at the Chinese Academy of Sciences with the Pd(II)-catalyzed vinylation of styrenes with aminals (e.g. 6 + 7 to 8). Eun Jin Cho at Hanyang University showed (J. Org. Chem. 2012, 77, 11383) that alkenes such as 9 could be trifluoromethylated with iodotrifluoromethane under visible light photoredox catalysis. David A. Nicewicz at the University of North Carolina at Chapel Hill developed (J. Am. Chem. Soc. 2012, 134, 18577) a photoredox procedure for the anti-Markovnikov hydroetherification of alkenols such as 11, using the acridinium salt 12 in the presence of phenylmalononitrile (13). A unique example of “catalysis through temporary intramolecularity” was reported (J. Am. Chem. Soc. 2012, 134, 16571) by André M. Beauchemin at the University of Ottawa with the formaldehyde-catalyzed Cope-type hydroamination of allyl amine 15 to produce the diamine 16. A free radical hydrofluorination of unactivated alkenes, including those bearing complex functionality such as 17, was developed (J. Am. Chem. Soc. 2012, 134, 13588) by Dale L. Boger at Scripps, La Jolla. Jennifer M. Schomaker at the University of Wisconsin at Madison reported (J. Am. Chem. Soc. 2012, 134, 16131) the copper-catalyzed conversion of bromostyrene 19 to 20 in what was termed an activating group recycling strategy. A rhodium complex 23 that incorporates a new chiral cyclopentadienyl ligand was developed (Science 2012, 338, 504) by Nicolai Cramer at the Swiss Federal Institute of Technology in Lausanne and was shown to promote the enantioselective merger of hydroxamic acid derivative 21 and styrene 22 to produce 24.
Streszczenia konferencji na temat "Pd-C core"
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Reichelt, Florian, Daniel Holder, Paulina Bosch i Thomas Maier. "How to support the appropriate method selection in design-technology-convergence?" W 13th International Conference on Applied Human Factors and Ergonomics (AHFE 2022). AHFE International, 2022. http://dx.doi.org/10.54941/ahfe1002234.
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Technical products have an increasing variety of functions. This leads, on the one hand, to a continuously increasing product complexity. On the other hand, the actual development work also becomes more complex. Due to this fact, interdisciplinary and flexible development is becoming essential to maintain competitiveness. Project managers are increasingly confronted with major decisions. They range from fundamental product decisions to the selection of suitable method support. In order to be able to make adequate decisions in this volatile and complex development environment, valid basis and support for decision-making are required. The aim of this contribution is, in the special context of the so-called design-technology convergence, i.e., the early stages of product development (PD), to provide both a possibility for determining and evaluating the project-status and a support for the selection of adequate development methods.METHODSOur investigation is divided into two core areas: On the one hand, Key-Performance-Indicators (KPIs) for the general tracking of the development project, especially in the convergence between design and technology development are investigated. On the other hand, we focused on other indicators for the selection of development methods.In a first step, a systematic literature review was conducted. Subsequently, known development methods and KPIs were analyzed regarding their suitability for application as indicators for method choice. Based on this fundamental consideration, interviews with experts in the field of design-technique-convergence (D-T-C) were conducted to extract process-typical indicators. Based on the research, the analysis as well as the results of the interviews, a first approach is derived how a decision support for the use of methods in a development project can be realized.RESULTSIt is apparent that product complexity is currently the main topic in the literature. This consists of various objectively describable factors and is directly correlated with development complexity. First research tries to make this development complexity manageable by organizational ways, like capacity-planning-tools. The possibility over purposeful and situational method selection to handle the complexity with the development is considered however only insufficiently. Also, for the evaluation of the project progress no specific approaches exist and are mostly only generically regarded. This is mainly due to a large variance in project-dependent conditions, which ultimately do not allow a transferable/comparable application of KPIs. Furthermore, especially in the early phases of the PD, there are still unspecific and evolving requirements that are difficult to objectify. Ultimately, the results show that a new approach is needed that not only takes into account a distinction between project-status indicators but also method indicators. CONCLUSION AND OUTLOOKIn the context of this contribution, we took a detailed look at the generic term "development complexity". Thereby, we primarily focused on the examination of the two components of this complexity form: project-status indicators and development step indicators. Lastly, we were able to derive a first approach for necessary indicators from the literature and from direct needs in the D-T-C. We will further develop these subsequently to create a decision support tool and evaluate the level of support.
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Rao, V. Pulagala, i Basava V. A. Rao. "Influence of Physical and Chemical Properties of Two Biodiesel Fuels on Performance, Combustion and Exhaust Emission Characteristics in a DI-CI Engine". W ASME 2008 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ices2008-1660.
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The purpose of this study is to examine the influence of biodiesel (BD) fuel properties on different characteristics of the engine and to compare with the baseline petroleum diesel (PD) fuel. This study consists of two parts, first one is biodiesel characterization and the second one is testing in the engine. Two BD fuels namely, the medium chain (C6–C24) coconut oil methyl ester (COME) and the long chain (C16–C18) sesame seed oil methyl ester (SSME) were selected. It is observed that, the physical and chemical properties such as viscosity, density, bulk modulus, calorific value, C/H ratio, and iodine value of SSME are higher than that of COME, while the cetane number, saturation% and oxygen% of the COME is higher than that of SSME. Experiments were conducted in a naturally aspirated, single cylinder, four-stroke, stationary, water cooled, constant rpm (1500), in-line (pump-high pressure tube-fuel injector) direct injection compression ignition (DI–CI) engine with COME, SSME (with and without preheating), and PD as fuels. The performance was evaluated in terms of fuel consumption (FC), brake specific energy consumption (BSEC), and thermal efficiency (BTE). Except for COME at full load, the BTE of the esters over all load ranges were less than that of PD fuel. Also, a significant improvement in BTE was observed, when the SSME is tested at PD’s viscosity by using preheating technique. At full load, the BSFC of COME and SSME are increased by 16.61% and 18.24% respectively. The minimum BSEC (at full load) of COME is decreased by 1.3% and while that of SSME is increased by 4.5%, as compared to that of PD fuel. The full load peak pressures for COME, SSME and PD fuel are 63.8 bar, 65.8 bar, and 62.9 bar respectively. The high peak pressures of the methyl esters are probably due to dynamic injection advance, caused by their higher bulk modulus. The net heat release rate (HRR) and cumulative heat release (CHR) were calculated from the acquired data. The results show that, at all loads there is a slight increase in peak HRR for COME and large increase in peak HRR for SSME against PD fuel. The higher values of peak HRR indicate better premixed combustion with the methyl esters. However, the peak HRR for preheated SSME (SSME_H) decreases due to late injection and faster evaporation of the fuel. It was observed that, at full load the nitric oxide (NO) emission of SSME is increased by 12.9%, while that of COME is decreased by 13.8% as compared to that of PD fuel. The smoke is increasing linearly with the fuels ‘C/H’ ratio regardless of their molecular structure. The HC emissions of both the esters are very low and are reduced by up to 73%, as compared PD. Also, there is a significant reduction in all exhaust emissions, and in particular the NO emission is observed with preheated SSME, due to change in premixed combustion phase.
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Mathkar, Ameya, Shyam Gopalakrishnan i Sujay S. Pathre. "Design of Ellipsoidal and Torispherical Heads in Pressure Vessel and Review of Restrictions in Material Strength Imposed in ASME Sec. VIII Div. 1: A Comparative Study of Various Codes of Constructions". W ASME 2022 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/pvp2022-84770.
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Abstract Pressure Vessels are made with various types of end closures. Commonly used end closures are ellipsoidal dished ends, torispherical dished end and hemispherical dished ends. For design of these end closures the rules provided in ASME Sec. VIII Div. 1[1] and ASME Sec. VIII Div. 2[2] differ significantly and a similar phenomenon could be observed when a review is done against popular international Code(s) for pressure vessel design like PD 5500 [3], EN 13445 [4]. The difference in the design methodology is due to the design approach used in developing the equations in these Code(s) of Construction. ASME Sec. VIII Div.1 in Para UG-32(d) and in Appendix 1–4 (c) & (d), end note 88 for design of all torispherical heads subject to internal pressure states that the maximum allowable stress used to calculate the required thickness cannot exceed 20 ksi (138 MPa) at room temperature irrespective of the strength of the material. This restriction is further reduced in proportion at elevated temperatures. Similar kinds of a restriction in the allowable stress is imposed for design of ellipsoidal heads when the factor K (shape factor in the design of ellipsoidal head) exceeds 1.0 in ASME Sec. VIII Div. 1. If we refer to other Code(s) like ASME Sec. VIII Div.2 and PD 5500 and EN 13445, one can observe that the restriction of allowable stress in the design of ellipsoidal and torispherical heads are not imposed when high strength materials are selected for the construction of dished ends. The work reported in this paper is an attempt to review the design methodology adopted for design of ellipsoidal dished ends with K exceeding 1.0 and all torispherical heads according to ASME Sec. VIII Div. 1 with ASME Sec. VIII Div. 2, PD 5500 and EN 13445 and to evaluate whether the restriction in the allowable stress imposed by ASME Sec. VIII Div. 1 is really required. Also, FEA of the dished ends are carried out to determine the stresses induced and a comparison is made against various Code(s) classical formula requirements.
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de Groot, Sander, Roland Dubourg, Klaas Bakker, Martin Kissane i Marc Barrachin. "Fission-Product Behaviour During Irradiation of TRISO-Coated Particles in the HFREU1bis Experiment". W Fourth International Topical Meeting on High Temperature Reactor Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/htr2008-58125.
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The irradiation experiment HFR-EU1bis, coordinated by the European Joint Research Centre – Institute for Energy, was performed in the High Flux Reator (HFR) at Petten to test five spherical HTR fuel pebbles of former German production with TRISO coated particles in conditions beyond the specifications of current HTR reactor designs (central temperature of 1250°C). In this paper, the behaviour of the fission products (FPs) and kernel micro-structure evolution during the test are investigated. While FP behaviour is a key issue for potential source term evaluation it also determines the evolution of the oxygen potential in the oxide kernel which in turn is important for formation of carbon oxides (amoeba effect and pressurization). Fission-gas release from the kernel can induce additional mechanical loading and finally some FPs (Ag, Cs, Sr) might alter the mechanical integrity of the coatings. This study is based on postirradiation examinations (ceramography + EPMA) performed both on UO2 kernels and on coatings. Significant evolutions of the kernel as a function of temperature are shown (grain structure, porosity, size of metallic inclusions). The quality of the ceramography results allows characteristics of the intergranular bubbles in the kernel (and estimation of swelling) to be determined. Remarkable results considering FP release from the kernel have been observed and will be presented. Examples are the significant release of Cs out of the kernel as well as Pd, whereas Zr remains trapped. Mo and Ru are mainly incorporated in metallic precipitates. These observations are interpreted and mechanisms for FP and micro-structural evolutions are proposed. These results are coupled to the results of calculations performed with the mechanistic code MFPR (Module for Fission Product Release) and the thermodynamic database MEPHISTA (Multiphase Equilibria in Fuels via Standard Thermodynamic Analysis). The effect of high flux rate and high temperature on fission gas behaviour, grain size evolution and kernel swelling are discussed. In addition, solid-FP behaviour (Cs, Mo, Zr, Ba, Sr) is discussed in connection with the evolution of kernel oxygen potential and evolution of the pressure of carbon oxides. The paper intends to be exemplary on how the combination of post-irradiation examination results and fuel modelling increases fundamentally the understanding of HTR fuel behaviour.