Littérature scientifique sur le sujet « Catalasi »
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Articles de revues sur le sujet "Catalasi"
1
Fusaroli, Federica. « La traduzione della «Somme le roi» tra Occitania e Catalogna : primi sondaggi ». Mot so razo 20 (25 janvier 2022) : 1. http://dx.doi.org/10.33115/udg_bib/msr.v20i0.22744.
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<p>RIASSUNTO: Il presente lavoro mira a fornire nuovi appunti sulle conoscenze circa la traduzione catalana della <em>Somme le roi</em>, compendio morale francese composto nel 1279 dal domenicano Frère Laurent e di grande successo lungo tutto il xiv secolo. Le forti analogie con la versione occitanica della <em>Somme</em>, nota anche come <em>Libre de vicis et de vertutz</em>, lasciano presumere che il testo catalano discenda proprio dalla traduzione occitana e non dall’originale francese. Il caso di studio è reso difficile dalla mancanza di lezioni erronee imputabili al processo di traduzione e dalle complicazioni imputabili alla probabile concomitanza di più fonti, in occitano e in francese, dietro l’allestimento della versione catalana. In ragione di ciò, il contributo si sofferma a illustrare le due tradizioni testuali – catalana e occitana – mettendo a confronto i dati tratti dall’edizione critica del <em>Libre de vicis et vertutz</em>, di futura pubblicazione, con lo studio di Wittlin (1983) sul testo catalano. Il discorso si concentra principalmente su due questioni cruciali: la <em>reductio ad unum</em> dei testimoni catalani e la scelta di includere nella <em>recensio</em> occitana un testimone trascritto in catalano.<br /><br /></p><p>ABSTRACT: This paper aims at updating the scholarship on the 14th-century Catalan translation of the French moral <em>compendium</em> known as <em>Somme le roi</em>. The relevant similarities between the texts demonstrate that the Catalan version directly depends on the Occitan translation, known as <em>Libre de vicis et de vertutz</em>. Therefore, the paper illustrates both the Catalan and the Occitan textual traditions and compares the results of my critical edition of the <em>Libre de vicis et vertutz</em> with Wittlin’s study (1983) on the Catalan text. This examination will focus on two main critical issues: the <em>reductio ad unum</em> of all the Catalan manuscripts and the choice to include a Catalan manuscript in the Occitan <em>recensio</em>.</p>
2
Hidayati, Nur, Rahmah Puspita Sari et Herry Purnama. « Catalysis of glycerol acetylation on solid acid catalyst : a review ». Jurnal Kimia Sains dan Aplikasi 23, no 12 (14 janvier 2021) : 414–23. http://dx.doi.org/10.14710/jksa.23.12.414-423.
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Biodiesel is a substitute fuel that is environmentally friendly, biodegradable, and sustainable. The need for biodiesel continues to increase. Biodiesel is made through the process of transesterification of triglycerides and alcohol. Glycerol is a side-effect of biodiesel products with a capacity of 10% of the total weight of its production. Glycerol is the simplest glyceride compound and has several functions as a primary ingredient in chemical production. Through acetylation, glycerol is converted to a material that has a higher sale value. Both homogeneous and heterogeneous catalysts are the acetylation approach to achieve the desired product, namely acetyl glycerol esters (mono-, di- and triacetin). However, in the process, the catalyst’s type and characteristics significantly affect the yield and conversion of the product and the deactivation or reusability of the catalyst, which can inhibit the catalyst’s utilization and effectiveness; therefore, it must be studied further. Besides, the parameters that affect the reaction will also be assessed.
3
Ripa, Valentina. « Omaggio a Joan Vinyoli ». SCRIPTA. Revista Internacional de Literatura i Cultura Medieval i Moderna 5, no 5 (12 juin 2015) : 305. http://dx.doi.org/10.7203/scripta.5.6377.
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Riassunto: In continuità con l’omaggio a Joan Vinyoli organizzato a Roma nel 2014, si propongono le traduzioni in italiano di alcuni suoi componimenti, con testo a fronte. Parole chiave: Joan Vinyoli, traduzione dal catalano all’italiano, poesia catalana del Novecento. Abstract: In continuity with the Joan Vinyoli Tribute organized in Rome in December 2014, I propose the translation from Catalan to Italian of some of his poems. Keywords: Joan Vinyoli, translation from Catalan to Italian, twentieth-century Catalan poetry.
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Ortega-Caballero, Fernando, et Mikael Bols. « Cyclodextrin derivatives with cyanohydrin and carboxylate groups as artificial glycosidases ». Canadian Journal of Chemistry 84, no 4 (1 avril 2006) : 650–58. http://dx.doi.org/10.1139/v06-039.
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Two cyclodextrin derivatives (1 and 2) were prepared in an attempt to create glycosidase mimics with a general acid catalyst and a nucleophilic carboxylate group. The catalysts 1 and 2 were found to catalyse the hydrolysis of 4-nitrophenyl β-D-glucopyranoside at pH 8.0, but rapidly underwent decomposition with loss of hydrogen cyanide to convert the cyanohydrin to the corresponding aldehyde. The initial rate of the catalysis shows that the cyanohydrin group in these molecules functions as a good catalyst, but that the carboxylate has no positive effect. The decomposition product aldehydes display little or no catalysis. A mechanism for the decomposition is suggested.Key words: biomimicry, enzyme model, kinetics, intramolecular reaction.
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Puigmalet, Joan. « Un vocabulari pornogràfic francès-català inèdit ». SCRIPTA. Revista Internacional de Literatura i Cultura Medieval i Moderna 3, no 3 (28 juin 2014) : 291. http://dx.doi.org/10.7203/scripta.3.3824.
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Resum: Antoni Bulbena Tosell és autor d’un manuscrit, i inèdit, vocabulari pornogràfic francès-català català-francès, la Flora pornogràfica francesa: suplement al argot francès / Flore pornographique catalane: supplément à l’argot catalan. És una obra d’aproximadament l’any 1921 que, per la seva temàtica, ell mateix reservava per a no publicar-se. Bulbena és autor d’una discutida obra lingüística, entre la qual trobem diferents diccionaris, alguns d’ells entre el català i el francès. El darrer que publicà és el Diccionari de les lléngues francesa & catalana / Dictionnaire catalan-français (1921) que inclou dos apèndixs, un «Vocabulari d’argot francès» i un «Vocabulari d’argot catalan». La Flora és, així, un suplement al lèxic pornogràfic d’aquest diccionari. Per altra banda, el títol de Flora pornogràfica sembla fer referència a una obra de la lexicografia francesa que recull mots obscens presents a obres d’Emile Zola i altres escriptors naturalistes, La flore pornographique (1883), d’Ambroise Macrobe. Els mots d’argot sexual de la Flora, amb un especial focus temàtic en la prostitució, tenen interès lingüístic i cultural tant per a la llengua catalana com per a la llengua francesa. Paraules clau: Antoni Bulbena, Flora pornogràfica, lexicografia, català, francès. Abstract: Antoni Bulbena Tosell is the author of an unpublished, pornographic vocabulary French-Catalan Catalan-French, a manuscript called the Flora pornogràfica francesa: suplement al argot francès / Flore pornographique catalane: supplément à l’argot catalan. It was written around 1921 and reserved for not being published. Bulbena is the author of a controversial linguistic work, among which are various dictionaries, some of them between Catalan and French. The latest is the Diccionari de les lléngues francesa & catalana / Dictionnaire catalan-français (1921), that includes two appendixes, a «Vocabulari d’argot francès» and a «Vocabulari d’argot catalan». The Flora is thus a pornographic supplement to the lexicon of these vocabularies. Moreover, the title Flora pornogràfica seems to refer to a pornographic French lexicography work that contains obscene words from books by Émile Zola and other naturalist writers: La flore pornographique (1883) by Ambroise Macrobe. Slang sexual terms from the Bulbena’s Flora, with a special focus on the theme of prostitution, have linguistic and cultural interest both for the Catalan and the French language Keywords: Antoni Bulbena, Flora pornogràfica, lexicography, Catalan, French.
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Kato, Shigeru, Takafumi Ueno, Shunichi Fukuzumi et Yoshihito Watanabe. « Catalase Reaction by Myoglobin Mutants and Native Catalase ». Journal of Biological Chemistry 279, no 50 (2 septembre 2004) : 52376–81. http://dx.doi.org/10.1074/jbc.m403532200.
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The catalase reaction has been studied in detail by using myoglobin (Mb) mutants. Compound I of Mb mutants (Mb-I), a ferryl species (Fe(IV)=O) paired with a porphyrin radical cation, is readily prepared by the reaction with a nearly stoichiometric amount ofm-chloroperbenzoic acid. Upon the addition of H2O2to an Mb-I solution, Mb-I is reduced back to the ferric state without forming any intermediates. This indicates that Mb-I is capable of performing two-electron oxidation of H2O2(catalatic reaction). Gas chromatography-mass spectroscopy analysis of the evolved O2from a 50:50 mixture of H218O2/H216O2solution containing H64D or F43H/H64L Mb showed the formation of18O2(m/e= 36) and16O2(m/e= 32) but not16O18O (m/e= 34). This implies that O2is formed by two-electron oxidation of H2O2without breaking the O-O bond. Deuterium isotope effects on the catalatic reactions of Mb mutants and catalase suggest that the catalatic reactions ofMicrococcus lysodeikticuscatalase and F43H/H64L Mb proceed via an ionic mechanism with a small isotope effect of less than 4.0, since the distal histidine residue is located at a proper position to act as a general acid-base catalyst for the ionic reaction. In contrast, other Mb mutants such as H64X (Xis Ala, Ser, and Asp) and L29H/H64L Mb oxidize H2O2via a radical mechanism in which a hydrogen atom is abstracted by Mb-I with a large isotope effect in a range of 10–29, due to a lack of the general acid-base catalyst.
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Yuzugullu, Yonca, Chi H. Trinh, Lucy Fairhurst, Zumrut B. Ogel, Michael J. McPherson et Arwen R. Pearson. « Investigating the active centre of theScytalidium thermophilumcatalase ». Acta Crystallographica Section F Structural Biology and Crystallization Communications 69, no 4 (28 mars 2013) : 369–75. http://dx.doi.org/10.1107/s1744309113004211.
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Almost all monofunctional haem catalases contain a highly conserved core containing the active site, which is connected to the exterior of the enzyme by three channels. These channels have been identified as potential routes for substrate flow and product release. To further investigate the role of these molecular channels, a series of mutants ofScytalidium thermophilumcatalase were generated. The three-dimensional structures of four catalase variants, N155A, V123A, V123C and V123T, have been determined at resolutions of 2.25, 1.93, 1.9 and 1.7 Å, respectively. The V123C variant contains a new covalent bond between the S atom of Cys123 and the imidazole ring of the essential His82. This variant enzyme has only residual catalase activity and contains haembinstead of the normal haemd. The H82A variant demonstrates low catalase and phenol oxidase activities (0.2 and 20% of those of recombinant wild-type catalase–phenol oxidase, respectively). The N155A and N155H variants exhibit 4.5 and 3% of the wild-type catalase activity and contain haemd, showing that Asn155 is essential for catalysis but is not required for the conversion of haembto haemd. Structural analysis suggests that the cause of the effect of these mutations on catalysis is the disruption of the ability of dioxygen substrates to efficiently access the active site. Additional mutants have been characterized biochemically to further probe the roles of the different channels. Introducing smaller or polar side chains in place of Val123 reduces the catalase activity. The F160V, F161V and F168V mutants show a marked decrease in catalase activity but have a much lower effect on the phenol oxidase activity, despite containing substoichiometric amounts of haem.
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Martí-Badia, Adrià. « Llengua i identitat en l’obra de Benvingut Oliver i Joan Baptista Perales ». SCRIPTA. Revista Internacional de Literatura i Cultura Medieval i Moderna 6, no 6 (29 décembre 2015) : 120. http://dx.doi.org/10.7203/scripta.6.7827.
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Resum: Aquest treball es proposa analitzar la reacció dels erudits valencians Benvingut Oliver i Joan Baptista Perales davant els postulats de la filologia romànica sobre el català en la segona meitat del segle XIX. A més, tractem de relacionar la posició d’Oliver i Perales amb altres erudits i escriptors del moviment reinaixencista i amb la consciència de comunitat lingüística compartida amb catalans, balears i nord-catalans. A partir de la meitat del Vuitcents els romanistes germànics funden la filologia romànica i constaten que el català és el nom de la llengua pròpia dels territoris de llengua catalana, diferent de l’occità i sense res a veure amb el llemosí amb què era conegut des de principis del segle xvi. Aquests postulats respecte a la identitat i el nom de la llengua catalana són ràpidament rebuts i acceptats a Catalunya; i a les Illes Balears i a la Catalunya del Nord foren rebuts positivament amb molt poques excepcions. Però no així al País Valencià, on només una minoria d’erudits com Benvingut Oliver i Joan B. Perales –entre d’altres– va acceptar i divulgar aquests postulats. Paraules clau: Segle XIX, Nom i identitat de la llengua catalana, Renaixença Valenciana, Benvingut Oliver, Joan Baptista Perales Abstract: This paper analyses the reaction of the Valencian scholars Benvingut Oliver and Joan Baptista Perales against postulates on the Catalan Romance philology in the middle of the nineteenth century. Moreover, this work tries to relate Oliver and Perales position with others scholars and writers of the Reinaixença Valenciana movement and the awareness of linguistic community shared with Catalan speakers from Catalonia, the Balearic Islands and North Catalonia. From the middle of the nineteenth century the German romanists found the Romance philology. They established “Catalan” as the name of the language of the Catalan-speaking areas. Even this is different from Occitan and has nothing to do with Limousin, which was known by this name since the early sixteenth century. Regarding the identity and the name of the Catalan language, these assumptions are quickly received and assumed in Catalonia. Although in the Balearic Islands and North Catalonia they were received positively with very few exceptions. Whereas in Valencia, only a minority of scholars like Benvingut Oliver and Joan B. Perales –among others– accepted and disseminated these postulates. Keywords: Nineteenth century, Name and identity of the Catalan language, Valencian Renaissance, Benvingut Oliver, Joan Baptista Perales
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Jiménez-Salcedo, Juan. « Quelques pistes méthodologiques en démolinguistique : la langue catalane et son Enquête d’usages linguistiques ». Articles 40, no 1 (9 décembre 2011) : 13–38. http://dx.doi.org/10.7202/1006630ar.
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Notre article présente la méthodologie et les résultats de l’Enquesta d’usos lingüístics 2008 (EULP08), une enquête menée par l’Institut catalan de la statistique (Idescat), dont l’objectif principal et de dresser un portrait des usages linguistiques de la population catalane, et qui se base sur une conceptualisation ouverte et dynamique des catégorisations linguistiques. Nous pensons que la méthode de travail privilégiée par les statisticiens catalans peut contribuer à éclairer plusieurs aspects de la démolinguistique canadienne et québécoise.
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Paris, Sophie, Deborah Wysong, Jean-Paul Debeaupuis, Kazutoshi Shibuya, Bruno Philippe, Richard D. Diamond et Jean-Paul Latgé. « Catalases of Aspergillus fumigatus ». Infection and Immunity 71, no 6 (juin 2003) : 3551–62. http://dx.doi.org/10.1128/iai.71.6.3551-3562.2003.
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ABSTRACT Upon infection of a host, the pathogenic fungus Aspergillus fumigatus is attacked by the reactive oxygen species produced by phagocytic cells. Detoxification of hydrogen peroxide by catalases was proposed as a way to overcome this host response. A. fumigatus produces three active catalases; one is produced by conidia, and two are produced by mycelia. The mycelial catalase Cat1p was studied previously. Here we characterized the two other catalases, their genes, and the phenotypes of gene-disrupted mutants. CatAp, a spore-specific monofunctional catalase, is resistant to heat, metal ions, and detergent. This enzyme is a dimeric protein with 84.5-kDa subunits. The 749-amino-acid polypeptide exhibits high levels of similarity to the Aspergillus nidulans CatA catalase and to bacterial catalase HPII of Escherichia coli. In spite of increased sensitivity to H2O2, killing of ΔcatA conidia by alveolar macrophages and virulence in animals were similar to the killing of conidia by alveolar macrophages and virulence in animals observed for the wild type. In contrast to the Cat1p and CatAp catalases, the mycelial Cat2p enzyme is a bifunctional catalase-peroxidase and is sensitive to heat, metal ions, and detergent. This enzyme, an 82-kDa monomer, is homologous to catalase-peroxidases of several fungi and bacteria. Surprisingly, mycelium of the double Δcat1Δcat2 mutant with no catalase activity exhibited only slightly increased sensitivity to H2O2 and was as sensitive to killing by polymorphonuclear neutrophils as mycelium of the wild-type strain. However, this mutant exhibited delayed infection in the rat model of aspergillosis compared to infection by the wild-type strain. These results indicate that conidial catalase is not a virulence factor and that mycelial catalases transiently protect the fungus from the host.
Thèses sur le sujet "Catalasi"
1
Guo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/622.
Texte intégralRésumé :
Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.
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Guo, Chris. « Alkane Oxidation Catalysis by Homogeneous and Heterogeneous Catalyst ». University of Sydney. Chemistry, 2005. http://hdl.handle.net/2123/622.
Texte intégralRésumé :
Abstract Cobalt-based complexes are widely used in industry and organic synthesis as catalysts for the oxidation of hydrocarbons. The Co/Mn/Br (known as "CAB system") catalyst system is effective for the oxidation of toluene. The Co/Mn/Br/Zr catalyst system is powerful for the oxidation of p-xylene, but not for the oxidation of toluene. [Co3O(OAc)5(OH)(py)3][PF6] (Co 3+ trimer 5) is more effective than [Co3O(OAc)6(py)3][PF6] (Co 3+ trimer 6) as a catalyst in the CAB catalyst system. Higher temperatures favour the oxidation of toluene. Zr 4+ does not enhance the oxidation of toluene. Zr 4+ could inhibit the oxidation of toluene in the combination of Co/Br/Zr, Co/Mn/Zr or Co/Zr. NHPI enhances the formation of benzyl alcohol, but the formation of other by-products is a problem for industrial processes. Complex(es) between cobalt, manganese and zirconium might be formed during the catalytic reaction. However, attempts at the preparation of complexes consisting of Co/Zr or Mn/Zr or Co3ZrP or Co8Zr4 clusters failed. The oxidation of cyclohexane to cyclohexanone and cyclohexanol is of great industrial significance. For the homogeneous catalysis at 50 o C and 3 bar N2 pressure, the activity order is: Mn(OAc)3 �2H2O > Mn12O12 cluster > Co 3+ trimer 6 > [Co3O(OAc)3(OH)2(py)5][PF6]2 (Co 3+ trimer 3) > Co 3+ trimer 5 > Co(OAc)2 �4H2O > [Co2(OAc)3(OH)2(py)4][PF6]-asym (Co dimerasym) > [Co2(OAc)3(OH)2(py)4][PF6]-sym (Co dimersym); whereas [Mn2CoO(OAc)6(py)3]�HOAc (Mn2Co complex) and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. But at 120 o C and 3 bar N2 pressure, the activity order is changed to: Co dimerasym > Co(OAc)2 �4H2O > Co trimer 3 and Mn(OAc)3 �2H2O > Co 3+ trimer 6 > Mn2Co complex > Co 3+ trimer 5 > Co dimersym > Mn12O12 cluster. The molar ratio of the products was close to cyclohexanol/cyclohexanone=2/1. Mn(II) acetate and zirconium(IV) acetate hydroxide showed almost no activity under these conditions. Among those cobalt dimers and trimers, only the cobalt dimerasym survived after the stability tests, this means that [Co2(OAc)3(OH)2(py)4][PF6]-asym might be the active form for cobalt(II) acetate in the CAB system. Metal-substituted (silico)aluminophosphate-5 molecular sieves (MeAPO-5 and MeSAPO-5) are important heterogeneous catalysts for the oxidation of cyclohexane. The preparation of MeAPO-5 and MeSAPO-5 and their catalytic activities were studied. Pure MeAPO-5 and MeSAPO-5 are obtained and characterised. Four new pairs of bimetal-substituted MeAPO-5 and MeSAPO-5(CoZr, MnZr, CrZr and MnCo) were prepared successfully. Two novel trimetal-subtituted MeAPO-5 and MeSAPO-5 (MnCoZr) are reported here. Improved methods for the preparation of four monometal-substituted MeAPO-5 (Cr, Co, Mn and Zr) and for CoCe(S)APO-5 and CrCe(S)APO-5 are reported. Novel combinational mixing conditions for the formation of gel mixtures for Me(S)APO-5 syntheses have been developed. For the oxidation of cyclohexane by TBHP catalysed by MeAPO-5 and MeSAPO-5 materials, CrZrSAPO-5 is the only active MeSAPO-5 catalyst among those materials tested under conditions of refluxing in cyclohexane. Of the MeAPO-5 materials tested, whereas CrCeSAPO-5 has very little activity, CrZrAPO-5 and CrCeAPO-5 are very active catalysts under conditions of refluxing in cyclohexane. MnCoAPO-5, MnZrAPO-5 and CrAPO-5 are also active. When Cr is in the catalyst system, the product distribution is always cyclohexanone/cyclohexanol equals 2-3)/1, compared with 1/2 for other catalysts. For MeAPO-5, the activity at 150 o C and 10 bar N2 pressure is: CrZrAPO-5 > CrCeAPO-5 > CoZrAPO-5. For MeAPO-5 and MeSAPO-5, at 150 o C and 13 bar N2 pressure, the selectivity towards cyclohexanone is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5; and the selectivity towards cyclohexanol is: MnZrAPO-5 > CrZrAPO-5 > MnCoAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5. Overall the selectivity towards the oxidation of cyclohexane is: CrZrAPO-5 > CrZrSAPO-5 > CrCeAPO-5 > CrAPO-5 > MnCoAPO-5 > MnZrAPO-5. The amount of water in the system can affect the performance of CrCeAPO-5, but has almost no effect on CrZrAPO-5. Metal leaching is another concern in potential industrial applications of MeAPO-5 and MeSAPO-5 catalysts. The heterogeneous catalysts prepared in the present work showed very little metal leaching. This feature, coupled with the good selectivities and effectivities, makes them potentially very useful.
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Johnston, Eric. « New Tools for Green Catalysis : Studies on a Biomimetic Hybrid Catalyst and a Novel Nanopalladium Catalyst ». Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-65079.
Texte intégralRésumé :
The first part of this thesis describes an improved synthetic route to hybrid (hydroquinone-Schiff base)cobalt catalysts. Preparation of the 5-(2,5-hydroxyphenyl)salicylaldehyde building block was improved by altering the protective groups of the hydroquinone (HQ) starting material. Both protection and deprotection could be carried out under mild conditions, resulting in high yields. By optimizing the reaction conditions of the Suzuki cross-coupling, an efficient and inexpensive synthetic route with a good overall yield was developed. The second part describes the use of the hybrid catalyst as an electron transfer mediator (ETM) in the palladium-catalyzed aerobic carbocyclization of enallenes. By covalently linking the HQ to the cobalt Schiff-base complex the reaction proceeded at lower temperatures with a five-fold increase of the reaction rate compared to the previously reported system. The third part describes the application of the hybrid catalyst in the biomimetic aerobic oxidation of secondary alcohols. Due to the efficiency of the intramolecular electron transfer, the hybrid catalyst allowed for a lower catalytic loading and milder reaction conditions compared to the previous separate-component system. Benzylic alcohols as well as aliphatic alcohols were oxidized to the corresponding ketones in excellent yield and selectivity using this methodology. The fourth part describes the synthesis and characterization of highly dispersed palladium nanoparticles supported on aminopropyl-modified siliceous mesocellular foam. The Pd nanocatalyst showed excellent activity for the aerobic oxidation of a wide variety of alcohols under air atmosphere. Moreover, the catalyst can be recycled several times without any decrease in activity or leaching of the metal into solution. Finally, the fifth part describes the application of the Pd nanocatalyst in transfer hydrogenations and Suzuki coupling reactions. The catalyst was found to be highly efficient for both transformations, resulting in chemoselective reduction of various alkenes as well as coupling of a variety of aryl halides with various boronic acids in excellent yields. Performing the latter reaction under microwave irradiation significantly increased the reaction rate, compared to conventional heating. However, no significant increase in reaction rate was observed for the transfer hydrogenations, under microwave heating.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 5: Manuscript.
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Markovits, Iulius [Verfasser]. « Ionic Liquids in Oxidation Catalysis : from Solvent to Catalyst / Iulius Markovits ». München : Verlag Dr. Hut, 2017. http://d-nb.info/1126297577/34.
Texte intégral
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Ford, David Dearborn. « The Role of Catalyst-Catalyst Interactions in Asymmetric Catalysis with (salen)Co(III) Complexes and H-Bond Donors ». Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11154.
Texte intégralRésumé :
In asymmetric catalysis, interactions between multiple molecules of catalyst can be important for achieving high catalyst activity and stereoselectivity. In Chapter 1 of this thesis, we introduce catalyst-catalyst interactions in the context of the classic Kagan nonlinear effect (NLE) experiment, and present examples of the strengths and drawbacks of the NLE experiment. For the remainder of the thesis, we explore catalyst-catalyst interactions in the context of two different reactions. First, in Chapter 2, we apply a combination of reaction kinetics and computational chemistry to a reaction that is well known to require the cooperative action of two molecules of catalyst: the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides. In our investigation, we demonstrate that stereoselectivity in the HKR is achieved through catalyst-catalyst interactions and provide a model for how high selectivity and broad substrate scope are achieved in this reaction. In Chapter 3, we focus our attention on the thiourea-catalyzed enantioselective alkylation of alpha-chloroethers with silyl ketene acetal nucleophiles, a reaction that was not known to require the cooperative action of two molecules of catalyst at the outset of our investigation. By using a wide range of physical organic chemistry tools, we established that the resting state of the optimal thiourea catalyst is dimeric under typical reaction conditions, and that two molecules of catalyst work cooperatively to activate the alpha-chloroether electrophile. The implications of this mechanism for catalyst design are discussed.Chemistry and Chemical Biology
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Montalat, Buscató Pere. « Lexicografia catalana siscentista : el Gazophylacium Catalano-Latinum, de Joan Lacavalleria i Dulac ». Doctoral thesis, Universitat de Girona, 2020. http://hdl.handle.net/10803/673089.
Texte intégralRésumé :
This dissertation is devoted to the study and partial edition of the Gazophylacium Catalano-Latinum by Joan Lacavalleria Dulac, a Catalan-Latin lexicographic thesaurus published in Barcelona in 1696 that constitutes the most extensive and exhaustive collection of Catalan lexicon of the seventeenth century.
This work begins with a historical search around the members of Lacavalleria family and their time. Secondly, the sources used by Lacavalleria are identified and the extent of their followup is studied in the elaboration of the Gazophylacium. Thirdly, the elements that make up the structure of the thesaurus and the nature of the vocabulary it contains are analyzed. Fourth, an account on the reception of the thesaurus and its subseqüent influence over Catalan lexicography and linguistics is given. Fifth, the adopted criteria for the critical edition of the selected texts are reported. Finally, I offer the texts edited according to the ecdotical criteria aforementionedAquesta tesi està dedicada a l’estudi i a l’edició parcial del Gazophylacium Catalano-Latinum, de Joan Lacavalleria i Dulac, un tresor lexicogràfic català-llatí publicat l’any 1696 a Barcelona que constitueix l’aplec de lèxic català més extens i exhaustiu de la dissetena centúria. El treball s’enceta amb una recerca històrica a l’entorn dels membres de la família Lacavalleria i de la seva època. En segon lloc, s’identifiquen les fonts emprades per Lacavalleria i s’estudia fins a quin punt les va seguir en l’elaboració del Gazophylacium; en tercer lloc, s’analitzen els elements que configuren l’estructura del diccionari i la naturalesa del lèxic que conté; en quart lloc, es tracta de la recepció de l’obra i de la seva influència sobre la lexicografia i la lingüística catalana posterior; en cinquè lloc, es reporten els criteris adoptats per a l’establiment dels textos d’aquest diccionari que edito críticament i, a l’últim, s’ofereixen els textos editats
Programa de Doctorat en Ciències Humanes, del Patrimoni i de la Cultura
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Sierra, salazar Andrés Felipe. « Waterborne catalytic materials with original design ». Thesis, Montpellier, Ecole nationale supérieure de chimie, 2017. http://www.theses.fr/2017ENCM0014/document.
Texte intégralRésumé :
Catalysis is one of the Green Chemistry Principles given its importance for limiting environmental impacts and improving current processes, as well as for developing new sustainable processes and products. In order to provide more performant catalysts, this study provides a novel preparation method for controlling the distribution of metal nanoparticles (NPs) within hierarchically meso- and macroporous catalysts. It consists of the combination of latex synthesis, sonochemistry and sol-gel process. All these steps can be carried out in water, reducing environmental impact. The first step is the synthesis of latex, typically polystyrene. The second step is the sonochemical synthesis and deposition of noble metal NPs on the surface of the latex polymer. The third step is the synthesis of the support by sol-gel process using tetraethyl orthosilicate (TEOS) under controlled conditions to modulate the porosity of the final silica matrix. As a result, an original catalyst morphology is obtained with active sites preferentially located within the macropores, which are surrounded by a mesoporous matrix. Using this approach, a monodisperse polystyrene latex (~130 nm) was prepared by emulsion polymerisation and then decorated with Pt NPs (~2.3 nm) by sonochemical reduction. The mesoporous silica support was prepared by sol-gel synthesis in the presence of the decorated latex. After calcination, the organic template left behind macropores with the Pt NPs within the generated macropores. Mesopores (2-15 nm) connecting these macropores (110-400 nm) were tuned by varying the synthesis conditions. Typically, specific surface areas of 615 m2/g and total pore volumes of 0.74 cm3/g were obtained. In a first case of study, hierarchically porous Pt/SiO2 catalysts were evaluated in the selective hydrogenation of p-chloronitrobenzene (p-CNB) to produce p-chloroaniline. They exhibited activities up to 91.7 ± 2.9 molCNB/(min molPt) and selectivity values up to 100 ± 2% at 80% of conversion, in comparison with 47.7 ± 2.9 molCNB/(min molPt) and 91 ± 2%, respectively, obtained with a commercial catalyst under the same conditions. Moreover, in a second case of study, it was possible to prepare silica-supported Pd, Pd-Pt and Pd-CeO2 catalysts with hierarchical porosity (meso and macro). These materials were tested in the direct synthesis of hydrogen peroxide from hydrogen and oxygen. The best productivity of H2O2 was obtained with the bimetallic Pd-Pt catalyst with 32500 molH2O2/(h molmetal) in batch, and the best selectivity was obtained with Pd-CeO2/SiO2 catalyst (63 ± 2%) in semi-batch. In summary, this thesis proposes a new aqueous preparation method for hierarchically porous functional materials by the combination of latex synthesis, sonochemical reduction and sol-gel process. It has been demonstrated that this preparation technique provides a very powerful and versatile toolbox for catalyst tailoring and optimisation. Further perspectives to achieve improved morphologies and controlled active sites distribution are also proposedLa catalyse est l'un des piliers pour le développement de procédés durables, car elle permet d'utiliser moins de ressources en accélérant les réactions chimiques. Afin de fournir des catalyseurs plus performants, cette étude propose une nouvelle méthode de préparation de catalyseurs pour contrôler la distribution de nanoparticules (NPs) métalliques au sein des catalyseurs hiérarchiquement poreux (méso et macro) en combinant la synthèse de latex, la réduction sonochimique et le procédé sol-gel. La première étape est la synthèse d'une empreinte porogène de billes de polystyrène (latex) obtenues par polymérisation en émulsion aqueuse. La deuxième étape est la synthèse et le dépôt de NPs de métaux nobles sur la surface des billes de polymère par voie sonochimique dans l’eau. La troisième étape est la synthèse du support catalytique par un procédé sol-gel en milieu aqueux en utilisant le latex décoré et l’orthosilicate de tétraéthyle (TEOS) dans des conditions contrôlées pour moduler la porosité finale de la matrice de silice (mésoporeuse). Toutes les étapes de cette approche sont effectuées dans l'eau, ce qui limite les impacts environnementaux de la préparation du catalyseur. L'élimination du porogène (latex) par calcination génère les macropores. Le matériau résultant possède alors une morphologie inédite pour un catalyseur, avec des macropores fonctionnalisés par des NPs métalliques, dans une matrice de silice mésoporeuse. Ainsi, il a été possible de synthétiser un latex monodisperse de polystyrène (~130 nm), lequel a été décoré avec des NPs de Pt (~2.3 nm) par réduction sonochimique. Le matériau final de silice a présenté des mésopores (2-15 nm) reliant les macropores (110-400 nm) contenant les NPs de Pt. Il a été possible d'obtenir des surfaces spécifiques et des volumes poreux totaux de 615 m2/g et 0,74 cm3/g, respectivement. Dans un premier cas d'étude, des catalyseurs de Pt/SiO2 à porosité hiérarchique ont été évalués dans l'hydrogénation sélective du p-chloronitrobenzene (p-CNB) pour produire la p-chloroaniline. Ils ont présenté des activités catalytiques allant jusqu'à 91,7 ± 2,9 molCNB/(min molPt) et des sélectivités jusqu'à 100 ± 2% à 80% de conversion, par rapport à 47,7 ± 2,9 molCNB/(min molPt) et 91 ± 2%, respectivement, obtenus dans les mêmes conditions avec un catalyseur commercial. Dans un deuxième cas d'étude, des catalyseurs à base de Pd, Pd-Pt et Pd-CeO2 supportés sur de la silice à porosité hiérarchique ont été préparés et testés dans la synthèse directe du peroxyde d'hydrogène. La meilleure productivité a été obtenue avec le catalyseur bimétallique Pd-Pt avec 32500 molH2O2/(h molmétal) en batch, et la meilleure sélectivité a été obtenue avec le catalyseur Pd-CeO2/SiO2 (63 ± 2%) en semi-continu. En résumé, cette thèse propose une nouvelle méthode de préparation dans l’eau de matériaux fonctionnels à porosité hiérarchique en combinant la synthèse de latex, la réduction sonochimique et le procédé sol-gel. Il a été démontré que cette technique de préparation fournit une boîte à outils très puissante et polyvalente pour la préparation et l'optimisation des catalyseurs. Des perspectives pour améliorer davantage les morphologies et la distribution contrôlée des sites actifs sont également proposées
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Chenneberg, Ludwig. « Nouvelles avancées en catalyse photoredox : applications en chimie radicalaire de synthèse et en catalyse duale ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066305/document.
Texte intégralRésumé :
L’objectif principal des travaux de recherche décrits dans ce manuscrit de thèse, est de concevoir de nouvelles méthodes de synthèse en chimie radicalaire et organométallique, de les associer dans une catalyse duale afin qu’elles puissent être appliquées à l’élaboration de briques moléculaires élaborées. Nous avons développé dans une première étude une alternative photocatalytique à la réaction de désoxygénation classique de Barton-McCombie d’alcools secondaires et tertiaires par l’hydrure de tributylétain. Celle-ci repose sur l’utilisation d’un précurseur O-thiocarbamate dérivé d’alcools pouvant être réduit par catalyse photorédox. Une étude mécanistique, basée sur des expériences de fluorescence et de voltammétrie cyclique, est aussi présentée. Dans une seconde étude, une élégante méthode de génération de radicaux alkyles non stabilisés, par photooxydation de « ate-complexes » de bore ou d’espèces hypervalentes à base de silicium est présentée. Ces radicaux sont piégés en présence d’accepteurs radicalaires ou engagés dans une catalyse duale avec des complexes de NickelVisible-light photoredox catalysis has emerged as a very powerful strategy to generate radical species replacing more and more tin-mediated or stoichiometric redox methodologies. The main objective of the research described in this Ph. D. thesis is to develop new synthetic methodologies in radical and organometallic chemistry, and merge them in a dual catalysis process for the preparation of elaborated molecular building blocks. In a first study, we report a photocatalytic alternative of Barton-McCombie deoxygenation based on a visible-light photoreduction of O-thiocarbamates derived from secondary and tertiary alcohols. A mechanistic investigation is presented based on fluorescence quenching and cyclic voltammetry experiments. In a second study, a challenging method of generation of unstabilized alkyl radicals by photooxidation of borate salts or hypervalent silicon species is reported. These radicals are trapped by free radical scavengers or engaged in a photoredox/nickel dual catalysis
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Verdaguer, i. Turró Miquel. « Jaume Serra Hunter i la teoria de la cultura en el Noucentisme ». Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/32058.
Texte intégralRésumé :
Catalan modern and contemporary philosophy has traditionally been little studied so strictly to historical and political reasons for more or less the same conviction that is compared with literature and even in historiography, it is a minor contribution. Some of the characters in the world of philosophy has been the Catalan Jaume Serra Hunter charismatic and versatile, whom history has done justice. Like many others, was persecuted in the Franco regime, declared outlawed and persecuted and exiled, first to France and then Mexico. This research aims to discover him and his huge role as a politician. But above all, I want to convey their deep love for culture and fierce defense that he did, especially Catalan, is following in philosophical discourse of his work. I figure Serra Hunter claim their struggle for cultural cohesion through its philosophy, making it reach everyone. I want to show how he worked in a time of crisis in society, culture and education, to overcome the crisis of philosophy as a guide. Serra Hunter lived a very difficult time for philosophy. But he wanted to bring all cultures. It is a philosophy that dealing with the issues may be even a sort of advanced in the world and some of the problems it has today. According to him, philosophy should be more human and more alive and present in all the different curriculum of any educational plan.La filosofia catalana moderna i contemporània ha estat tradicionalment molt poc estudiada tant per motius estrictament històrics i polítics com per la mateixa convicció més o menys compartida que, especialment si se la compara amb la literatura i, fins i tot, amb la historiografia, es tracta d'una aportació molt menor i de segon ordre. Uns dels personatges importants del món de la filosofia catalana ha estat el polifacètic i carismàtic Jaume Serra Hunter, al qual la història no ha fet justícia. Com tants altres, va ser un represaliat del franquisme, declarat fora de la llei i perseguit i exiliat, primer a França i després a Mèxic. Aquest treball d'investigació vol donar a conèixer la seva persona i la seva enorme tasca com a polític. Però, per damunt de tot, vull transmetre el seu profund amor per la cultura i la defensa aferrissada que en va fer, especialment de la catalana, seguint en fil discursiu de la seva obra filosòfica. Vull reivindicar la figura de Serra Hunter i la seva lluita per la cohesió cultural a través de la seva filosofia, fent-la arribar a tothom. Vull demostrar com va treballar, en una època de forta crisi de la societat, de la cultura i de l'educació, per sortir de la crisi amb la filosofia com a guia. Serra Hunter va viure una època de moltes dificultats per a la filosofia. Però ell volia fer arribar la cultura a tothom. La seva, és una filosofia, que amb els temes que tracta pot ser, fins i tot una mena d'avançada al món i a alguns dels problemes que aquest té avui en dia. Segons ell, la filosofia hauria de ser més humana i més viva i estar present en tots els diversos plans d'estudis de qualsevol pla educatiu.
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Han, Xu. « Development of innovative methodologies in phosphine organocatalysis and enantioselective gold(I)-catalysis ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS568.
Texte intégralRésumé :
Les phosphines jouent un rôle central dans la chimie organique moderne. Dans le domaine de la catalyse, les composés organophosphorés peuvent être appliqués soit en tant qu’organocatalyseurs dans de nombreuses transformations, soit en tant que ligands en catalyse organométallique. Au cours de cette thèse, nous avons utilisé les phosphines dans ces deux applications : en organocatalyse et en catalyse asymétrique à l’or(I). Dans la première partie, nous avons développé une réaction d’addition de Michael/réaction de Wittig intramoléculaire. Nous avons judicieusement choisi la phosphine utilisée ainsi que l’agent réducteur afin de permettre la réduction in situ de l’oxyde de phosphine correspondant. De nombreux dérivés 1,2-dihydroquinolines diversement fonctionnalisés ont pu être isolés avec de bons rendements. Parallèlement à cela, une nouvelle réaction d’oléfination a pu être découverte, donnant accès à des dérivés succinates. Un mécanisme réactionnel a pu être proposé, en se basant notamment sur des expériences de deutération. Dans un deuxième temps, nous nous sommes intéressés au développement de réactions énantiosélectives catalysées par des complexes chiraux d’or(I), et utilisant des substrats énynes. Une première réaction de cyclisation d’énynes-1,5, suivie d’une addition nucléophile a été développée en utilisant des complexes d’or de structure TADDOL-phosphoramidite-AuCl. Ce catalyseur a permis l’obtention de vingt dérivés cyclopentènes avec de bons rendements et des excès énantiomériques atteignant 94% ee. Finalement, des substrats énynes-1,6 correctement substitués ont été utilisés dans une réaction de cyclisation, suivie d’un piégeage intramoléculaire, afin de donner accès à des composés tétracycliques et pentacycliques complexes. Les composés racémiques ont été isolés avec de bons rendements et la version asymétrique a également été développée, par l’utilisation de complexes chiraux d’or(I)Phosphines play a major role in modern organic chemistry. In the field of catalysis, organophosphorus derivatives can be applied as catalysts in numerous transformations by itself, as organocatalysts, or as ligands in organometallic catalysis. This thesis focused on the application of phosphines both in phosphine organocatalysis and in asymmetric gold(I) catalysis. In the organophosphorus catalysis part, we have developed a phosphine-catalyzed Michael addition/Wittig reaction by using a well-chosen cyclic phosphine catalyst. In this process, silane was used as reducing agent to selectively reduce in situ the phosphine oxide. A series of highly functionalized 1,2-dihydroquinolines were prepared. Besides, a new olefination process was discovered for the synthesis of succinate derivatives. Detailed mechanism research was carried out with H/D exchange experiments. In the asymmetric gold(I) catalysis part, we have developed two new methodologies based on cyclization reactions of 1,n-enyne substrates. A 1,5-enyne cyclization/nucleophilic addition reaction was first developed with an acyclic TADDOL-derived phosphoramidite-Au(I) complex. Twenty examples were carried out with good to excellent yields and up to 94% enantiomeric excess. For the 1,6-enyne cyclization/intramolecular nucleophilic addition sequence, we have synthesized a range of racemic tetracyclic and pentacyclic compounds in high yields. The enantioselective version of this transformation was carried out successfully with both high reactivity and enantioselectivity
Livres sur le sujet "Catalasi"
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Corominas, Rossend Arqués i. Diccionari català-italià = : Dizionario catalano-italiano. Barcelona : Enciclopèdia Catalana, 1992.
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Dolcet, Josep. Música catalana impresa = : Catalan music in print. Barcelona : Generalitat de Catalunya, Departament de Cultura, 2002.
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Leandre, Villaronga, Galán Domingo Eduardo et Societat Catalana d'Estudis Numismàtics, dir. Catàleg general de la moneda catalana : Països Catalans i Corona Catalano-Aragonesa (s. V aC - S. XX dC). Barcelona : Societat Catalana d'Estudis Numismàtics, 2009.
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J, Thomas W., dir. Principles and practice of heterogeneous catalysis. Weinheim : VCH, 1996.
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(Firm), Larousse, dir. Larousse diccionari compact : Català-anglès, English-Catalan. Barcelona : Larousse Editorial, 2000.
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Derouane, Eric G., Francisco Lemos, Avelino Corma et Fernando Ramõa Ribeiro, dir. Combinatorial Catalysis and High Throughput Catalyst Design and Testing. Dordrecht : Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4329-5.
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G, Derouane E., dir. Combinatorial catalysis and high throughput catalyst design and testing. Dordrecht : Kluwer Academic Publishers, 2000.
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Grau, Román Perpiñá. D'economia catalana i mundial : Textos en català 1926-1986. Barcelona : Editorial Alta Fulla, 1989.
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Enantioselective titanium-catalysed transformations. New Jersey : Imperial College Press, 2015.
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Els Estudis Universitaris Catalans (1903-1985) : Per una Universitat Catalana. Barcelona : Institut d'Estudis Catalans, 2011.
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Ivancich, Anabella, et Peter C. Loewen. « Electron Transfer in Catalases and Catalase-Peroxidases ». Dans Encyclopedia of Biophysics, 1–5. Berlin, Heidelberg : Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-642-35943-9_51-1.
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Ivancich, Anabella, et Peter C. Loewen. « Electron Transfer in Catalases and Catalase-Peroxidases ». Dans Encyclopedia of Biophysics, 611–14. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-16712-6_51.
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Sachdeva, Garima, Dipti Vaya, Varun Rawat et Pooja Rawat. « Solid-supported Catalyst in Heterogeneous Catalysis ». Dans Heterogeneous Catalysis in Organic Transformations, 105–25. Boca Raton : CRC Press, 2022. http://dx.doi.org/10.1201/9781003126270-5.
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Balcells, Albert. « From Solidaritat Catalana to the Catalan Mancomunitat ». Dans Catalan Nationalism, 55–66. London : Palgrave Macmillan UK, 1996. http://dx.doi.org/10.1007/978-1-349-24278-8_6.
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Wong, Dominic W. S. « Catalase ». Dans Food Enzymes, 346–57. Boston, MA : Springer US, 1995. http://dx.doi.org/10.1007/978-1-4757-2349-6_12.
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Schomburg, D., M. Salzmann et D. Stephan. « Catalase ». Dans Enzyme Handbook 7, 741–46. Berlin, Heidelberg : Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-78521-4_141.
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Gooch, Jan W. « Catalase ». Dans Encyclopedic Dictionary of Polymers, 880. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13330.
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Bobrov, N. N., et V. N. Parmon. « Rapid Catalyst Testing in The Boreskov Institute of Catalysis ». Dans Principles and Methods for Accelerated Catalyst Design and Testing, 197–215. Dordrecht : Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0554-8_10.
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Ribaudo, Fabrizio, Piet W. N. M. van Leeuwen et Joost N. H. Reek. « Supramolecular Dendritic Catalysis : Noncovalent Catalyst Anchoring to Functionalized Dendrimers ». Dans Dendrimer Catalysis, 39–59. Berlin, Heidelberg : Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3418_031.
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Bényei, Attila C. « Hexaaquaruthenate(II) as Catalyst Precursor in Aqueous Organometallic Catalysis ». Dans Aqueous Organometallic Chemistry and Catalysis, 159–71. Dordrecht : Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0355-8_14.
Texte intégralActes de conférences sur le sujet "Catalasi"
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THOMAS, JOHN MEURIG. « HETEROGENOUS CATALYSIS AND CHARACTERIZATION OF CATALYST SURFACES ». Dans 24th International Solvay Conference on Chemistry. WORLD SCIENTIFIC, 2018. http://dx.doi.org/10.1142/9789813237179_0019.
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Wüthrich, Kurt, R. H. Grubbs, T. Visart de Bocarmé et Anne De Wit. « Heterogeneous Catalysis and Characterization of Catalyst Surfaces ». Dans 24th International Solvay Conference on Chemistry. WORLD SCIENTIFIC, 2018. http://dx.doi.org/10.1142/9789813237179_others02.
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Karkanis, Anastasios N., Pantelis N. Botsaris et Panagiotis D. Sparis. « A Catalyst Surface Control Automation System for Emission Reduction During Cold Start ». Dans ASME 2004 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/icef2004-0865.
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This paper presents and discusses experimental data obtained during test simulating the test cycle ECE-15 for a relatively simple method for the reduction of pollutant emissions during a cold start. During a cold start the volume of the exhaust gases is considerably smaller than the ones under full load. Therefore, only a small portion of the catalyst active surface is used to process the gases at the cold start phase. After the light-off at the initial surface the exhaust gases pass from the total catalytic surface which is already pre-heated from the first phase. The experimental results presented here indicate that there is a reduction of the pollutant emissions during the cold start of an engine. The developed system uses the 20% of the catalyst active surface during start-up and the rest of the catalyst surface after this phase, controlled by a proper automation system. At the cold start phase the system focusing the gas flow towards the center core of the monolith, so there is a quicker warm-up of the catalyst and a faster initiation of catalysis in this area. So when the remaining ceramic body of the catalytic converter is used, it is already warmed and the catalysis starts almost immediately.
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Rożeń, Antoni. « A Simple One-Dimensional Model of a Passive Hydrogen Recombiner ». Dans 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-31124.
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A simple one-dimensional model allowing fast predictions of: a gas composition and temperature profiles, a catalyst temperature profile and an overall hydrogen recombination degree has been developed for a passive catalytic recombiner. The model assumes that heat and mass transport processes, taking place in vertical channels between catalyst plates, occur in a highly non-isothermal, developing laminar gas flow and in conditions of mixed convection. A kinetic model of heterogeneous catalysis was implemented into the model and the heat radiation from the catalyst surface was accounted for. The model with no adjustable parameters was verified against experimental results available in literature and results of numerical simulations obtained by CFD methods.
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Fisher, Galen B., Joseph R. Theis, Mark V. Casarella et Stephen T. Mahan. « The Role of Ceria in Automotive Exhaust Catalysis and OBD-II Catalyst Monitoring ». Dans International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States : SAE International, 1993. http://dx.doi.org/10.4271/931034.
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Kawakami, Takashi, Tomiaki Furuya, Yukio Sasaki, Toshiyuki Yoshine, Yutaka Furuse et Mitsunobu Hoshino. « Feasibility Study on Honeycomb Ceramics for Catalytic Combustor ». Dans ASME 1989 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1989. http://dx.doi.org/10.1115/89-gt-41.
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This paper contains results of a structural feasibility study on honeycomb ceramic materials used for catalytic combustors in power gas turbines. Extruded cordierite honeycomb substrates are widely used as catalyst carriers in automotive exhaust systems, because of their excellent thermal shock resistance. For gas turbines, however, the ceramic catalyst carriers should retain the reliability at high temperature. In a hybrid catalytic combustor, which handles both catalysis and gas phases combustion, cordierite honeycomb structures (melt at 1445°C) can be adopted as the catalyst carrier, because the auxiliary gas phase combustion makes catalyst temperature lower than the conventional catalytic combustor. During this study, cordierite honeycomb (200 square cells/in2) tensile tests were carried out at high temperatures up to 1000°C. Using the finite element method, stresses in a cell wall were analyzed. The honeycomb cell wall mechanical strength was derived by comparing the experimental and analytical results. Also, combustor honeycomb cell stresses were calculated under typical oprerating conditions. Consequently, it was shown that it is sufficiently feasible to use the cordierite honeycomb structure as a catalyst carrier for hybrid catalytic combustors.
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Brus, Grzegorz, Zygmunt Kolenda, Shinji Kimijima et Janusz S. Szmyd. « An Analysis of Heat Transfer Processes in an Internal Indirect Reforming Type Solid Oxide Fuel Cell ». Dans 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22785.
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This paper presents experimental and numerical studies on the fuel reforming process on an Ni/YSZ catalyst. Nickel is widely known as a catalyst material for Solid Oxide Fuel Cells. Because of its prices and catalytic properties, Ni is used in both electrodes and internal reforming reactors. However, using Ni as a catalyst carries some disadvantages. Carbon formation is a major problem during a methane/steam reforming reaction based on Ni catalysis. Carbon formation occurs between nickel and metal-support, creating fibers which damage the catalytic property of the reactor. To prevent carbon deposition, the steam-to-carbon ratio is kept between 3 and 5 throughout the entire process. To optimize the reforming reactors, detailed data about the entire reforming process is required. In the present paper kinetics of methane/steam reforming on the Ni/YSZ catalyst was experimentally investigated. Measurements including different thermal boundary conditions, the fuel flow rate and the steam-to-methane ratios were performed. The reforming rate equation derived from experimental data was used in the numerical model to predict synthetic gas composition at the outlet of the reformer.
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Parks, James E. « Mitigation of Sulfur Effects on a Lean NOx Trap Catalyst by Sorbate Reapplication ». Dans ASME 2007 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/icef2007-1628.
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Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as “regeneration” since the catalyst is reactivated for more NOx trapping. Natural gas combusted over partial oxidation catalysts in the exhaust can be used to obtain the rich exhaust conditions necessary for catalyst regeneration. Thus, the lean NOx trap technology is well suited for lean natural gas engine applications. One potential limitation of the lean NOx trap technology is sulfur poisoning. Sulfur compounds directly bond to the NOx trapping sites of the catalyst and render them ineffective; over time, the sulfur poisoning leads to degradation in overall NOx reduction performance. In order to mitigate the effects of sulfur poisoning, a process has been developed to restore catalyst activity after sulfur poisoning has occurred. The process is an aqueous-based wash process that removes the poisoned sorbate component of the catalyst. A new sorbate component is reapplied after removal of the poisoned sorbate. The process is low cost and does not involve reapplication of precious metal components of the catalyst. Experiments were conducted to investigate the feasibility of the washing process on a lean 8.3-liter natural gas engine on a dynamometer platform. The catalyst was rapidly sulfur poisoned with bottled SO2 gas; then, the catalyst sorbate was washed and reapplied and performance was reevaluated. Results show that the sorbate reapplication process is effective at restoring lost performance due to sulfur poisoning. Specific details relative to the implementation of the process for large stationary natural gas engines will be discussed.
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López García, Esmeralda. « La mediterraneidad en la obra de Le Corbusier. La bóveda catalana lecorbuseriana : Influencias y evolución ». Dans LC2015 - Le Corbusier, 50 years later. Valencia : Universitat Politècnica València, 2015. http://dx.doi.org/10.4995/lc2015.2015.527.
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Resumen: Le Corbusier durante gran parte de su vida busca volver la vista hacia las tradiciones mediterráneas. Con el fin de desvelar la arquitectura y el paisaje españoles, realiza un gran número de viajes en tren y coche a lo largo de su territorio y será durante su visita a Barcelona en 1928 cuando nace su interés por la técnica de la bóveda catalana. Es una época de su carrera en la que empieza a interesarse por métodos de construcción y materiales tradicionales. Para el arquitecto la bóveda catalana es un sistema con grandes posibilidades formales y una gran flexibilidad frente a su sencillez de medios. Le Corbusier muestra la influencia de sus viajes por el Mediterráneo, en especial de su viaje a Barcelona, y de su relación con varios arquitectos españoles en una gran cantidad de obras residenciales realizadas entre los años 20 y 50. Consiguió definir la expresividad del proyecto a través de la repetición de un único elemento arquitectónico, el sistema abovedado sobre una retícula, y de la utilización de diversos materiales como el ladrillo, vidrio y hormigón. Tras años de estudios de estos elementos el arquitecto adapta la bóveda catalana a las innovaciones estructurales del hormigón armado, demostrando una gran autonomía formal y temporal respecto al resto de sus proyectos y consiguiendo aunar tradición y modernidad en una única obra. Abstract: Throughout his life Le Corbusier was inspired by Mediterranean traditions. In order to discover Spanish architecture and landscape, he went on numerous of car and train trips throughout its territory. During his visit to Barcelona in 1928 he discovered the craftsmanship of thin-tile Catalan vaults. This was a period in his career in which he began to be interested in traditional building methods and materials. Le Corbusier looked at Catalan vaults as a very flexible formal system versus its simplicity of means. He showed the influence of his travels around the Mediterranean, particularly when he travelled to Barcelona and his relationship with many Spanish architects, in a large number of residential projects built between the 20s and the 50s. He managed to define the project expressivity through the repetition of an unique architectural element, the vault on a grid system, and the use of different materials such as brick, glass and concrete. After several years studying these elements he was able to adapt the Catalan vault system to innovative reinforced concrete structural solutions, showing a great formal and temporary autonomy compared to the rest of his projects while combining tradition and modernity in a unique work.Palabras clave: Mediterráneo; viajes; bóveda catalana; tradición; modernidad. Keywords: Mediterranean; trips; Catalan vault; tradition; modernity. DOI: http://dx.doi.org/10.4995/LC2015.2015.527
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Graziani, M., et C. N. R. Rao. « Advances in Catalyst Design ». Dans Workshop on Catalyst Design. WORLD SCIENTIFIC, 1991. http://dx.doi.org/10.1142/9789814539029.
Texte intégralRapports d'organisations sur le sujet "Catalasi"
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Delgass, William Nicholas, Mahdi Abu-Omar, James Caruthers, Fabio Ribeiro, Kendall Thomson et William Schneider. Catalysis Science Initiative : Catalyst Design by Discovery Informatics. Office of Scientific and Technical Information (OSTI), juillet 2016. http://dx.doi.org/10.2172/1260972.
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Musselwhite, Nathan. The Catalysis of Uniform Metal Nanoparticles Deposited onto Oxide Supports : The Components of a Catalyst that Control Activity and Selectivity. Office of Scientific and Technical Information (OSTI), mai 2015. http://dx.doi.org/10.2172/1469158.
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Watkins, Thomas R., Michael J. Lance, Lawrence Frederick Allard, Jr, Krishna Kamasamudram et Aleksey Yezerets. Catalyst Characterization. Office of Scientific and Technical Information (OSTI), septembre 2014. http://dx.doi.org/10.2172/1157139.
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Davis, A., H. H. Schobert, G. D. Mitchell et L. Artok. Catalyst dispersion and activity under conditions of temperature- staged liquefaction. [Catalyst precursors for molybdenum-based catalyst and iron-based catalyst]. Office of Scientific and Technical Information (OSTI), juillet 1992. http://dx.doi.org/10.2172/7233290.
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Campbell, Charles T., Abhaya K. Datye, Graeme A. Henkelman, Raul F. Lobo, William F. Schneider, Leonard D. Spicer, Wilfred T. Tysoe et al. EMSL and Institute for Integrated Catalysis (IIC) Catalysis Workshop. Office of Scientific and Technical Information (OSTI), mai 2011. http://dx.doi.org/10.2172/1016448.
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Smith, K. J., et E. C. Sanford. Progress in catalysis. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1992. http://dx.doi.org/10.4095/304511.
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George A. Kraus. Center for Catalysis. Office of Scientific and Technical Information (OSTI), avril 2005. http://dx.doi.org/10.2172/838426.
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Alivisatos, A. P., Gabor A. Somorjai et Peidong Yang. Plasmonic-Enhanced Catalysis. Fort Belvoir, VA : Defense Technical Information Center, mai 2012. http://dx.doi.org/10.21236/ada576759.
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Krumova, Ekaterina, Nedelina Kostadinova, Jeni Miteva-Staleva, Galina Stoyancheva, Radoslav Abrashev, Vladislava Dishlijska, Boryana Spasova et Maria Angelova. Selection of Catalase Producers among Antarctic Fungi. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, février 2020. http://dx.doi.org/10.7546/crabs.2020.02.10.
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Munoz, V. A. Catalyst characterization : part i. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1993. http://dx.doi.org/10.4095/305312.
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