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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Étude de la spéciation exhaustive des lanthanides et des actinides pour les procédés de traitement du combustible nucléaire : approche intégrée par spectrométries de masse / Development of an HILIC method with simultaneous ESIMS and ICPMS detection for lanthanide and actinide speciation in nuclear fuel treatment processes

Blanchard, Evelyne 12 September 2018 (has links)
Dans ce travail, des méthodes d’analyses de spéciation exhaustive de lanthanides (Ln), en présence d'acides polyaminocarboxyliques (EDTA, DTPA) utilisés comme agents de desextraction dans les procédés de traitement de combustibles nucléaires usés, ont été développées par couplage simultané HILIC-ESIMS/ICPMS. Pour réduire les volumes d’effluents chromatographiques tout en maintenant des séparations efficaces et rapides, les performances de colonnes remplies de particules entièrement poreuses (FPP) et de particules superficiellement poreuses (SPP) ont été évaluées, aboutissant à la sélection de la technologie FPP de diamètre sub-2-µm. Selon la composition des échantillons, le couplage HILIC-ESIMS peut s'avérer suffisant pour des études de spéciation exhaustive, nécessitant l'évaluation du potentiel de l'ESIMS pour la mesure de composition isotopique d'éléments. Des méthodes de mesure de rapports isotopiques du natSm complexé à l'EDTA ont alors été développées avec deux types d’ESIMS, en introduisant directement l'échantillon. Une méthode de déconvolution a ensuite été développée pour déterminer les rapports isotopiques du natSm. L'approche a été validée avec un complexe de Sm enrichi en 147Sm et 149Sm. L'étape ultérieure a consisté à déterminer les rapports isotopiques du Sm avec le couplage simultané, en appliquant plusieurs méthodes de traitements de signaux transitoires. Des méthodes de quantification par étalonnage externe et par dilution isotopique spécifique ont été ensuite développées avec ce même complexe. Les développements réalisés avec le Sm pourront être étendus à d'autres lanthanides et aux actinides. / In this work, analysis methods of lanthanide (Ln) comprehensive speciation, in the presence of polyaminocarboxylic acids (EDTA, DTPA) used as back extraction agents in spent nuclear fuel treatment processes, were developed by simultaneous coupling HILIC-ESIMS/ICPMS. To reduce chromatographic effluent volumes while maintaining efficient and rapid separations, the performances of columns packed with fully porous particles (FPP) and superficially porous particles (SPP) were evaluated, resulting in the selection of the sub-2-µm FPP technology. Depending on the sample composition, HILIC-ESIMS coupling may be sufficient for comprehensive speciation studies, requiring assessment of the ESIMS potential for isotopic composition measurement of elements. The isotopic ratio measurement methods of natSm complexed with EDTA were then developed with two types of ESIMS, directly introducing the sample. A deconvolution method was then developed to determine the natSm isotope ratios. The approach was validated with Sm complex enriched in 147Sm and 149Sm. The next step was to determine the Sm isotopic ratios with the simultaneous coupling, by applying several methods of transient signal processing. Quantification methods by external calibration and specific isotopic dilution were then developed with this same complex. The developments carried out with Sm may be extended to other lanthanides and actinides.
202

Magnetic studies on lanthanide-based endohedral metallofullerenes

Velkos, Georgios 13 December 2021 (has links)
​My PhD thesis is an in-depth study of the magnetic properties of a series of different lanthanide-based endohedral metallofullerenes. They are sphere-like shape carbon molecules (fullerenes) with embedded magnetic lanthanide elements inside, suitable for spintronic and high dense-data storage applications. In this work, I studied two families of endohedral metallofullerenes (di-lanthanides and Dy-oxides) which showed great versatility in the magnetic behavior, depending on the type of the encapsulated cluster, and the size and shape of the carbon cage.:Magnetic studies on lanthanide dimetallofullerenes Gd2@C80(CH2Ph) and Gd2@C79N Tb2@C80(CH2Ph) and Tb2@C79N TbY@C80(CH2Ph) Ho2@C80(CH2Ph) Er2@C80(CH2Ph) Magnetic studies on Dy-oxide clusterfullerenes Dy2O@C72 Dy2O@C74 Dy2O@C82 (three isomers)
203

Příprava nesymetrických derivátů DOTA a studium jejich komplexů / Synthesis of unsymmetric DOTA derivatives and study of their complexes

Obuch, Jakub January 2021 (has links)
Lanthanide(III) complexes are compounds with both diagnostic and therapeutic applications. For diagnostic applications, they are used as contrast agents for imaging techniques such as MRI, PET or SPECT. In therapy, complexes of beta or alpha particle- emitting radionuclides are used. If the complexes contain protonable groups, their behaviour is dependent on pH of the solution. Protonation of these groups should occur close to the physiological pH. If the efficiency (relaxivity) of the MRI contrast agent is dependent on protonation state, this method can be used for determination of pH of tissues in vivo. For radiopharmaceuticals, fast complexation of short-lived metal radionuclides is important and protonation might significantly accelerate the complex formation. For therapeutic applications, possibility of labelling at low temperatures when heat-sensitive biovectors (e.g. antibodies) do not decompose. To assess the effect of protonation of amino group in the vicinity of the metal ion, amino-bis(phosphinate) pendant arm was proposed, where the dissociation constant of the amino group below the physiological pH can be expected. Three ligands containing this group and DO3A fragment were prepared and their complexes were studied to assess aforementioned possible uses in medicine. Their structure and...
204

Synthesis of a rotaxane with switchable lanthanide luminescence / Syntes av en rotaxan med modifierbar lantanidluminescens

Ramström, Anja January 2022 (has links)
I rotaxaner följs förflyttningen av makrocykeln vanligtvis med 1H-NMR spektroskopi. Målet med detta projekt är i stället att utveckla ett system som möjliggör att förflyttningen av makrocykeln kan observeras med hjälp av luminiscerande lantanid emission. Detta bör vara ett kraftfullt verktyg, då luminiscerande emission skulle möjliggöra att makrocykelns position längs med tråden kan avläsas direkt med blotta ögat. För att lantanid-baserade system ska kunna luminiscera krävs det att en aktiverande antennmolekyl finns i närheten av lantaniden. I detta projekt placerades en lantanidligand i den ena stoppande änden av en [2]rotaxan och en antennmolekyl sattes på den trådade makrocykeln. En förändring av pH:t medför att makrocykeln förflyttas närmre till lantanidliganden, vilket i sin tur medför att antennen aktiverar lantaniden och den luminiscerande emissionen startar. Baserat på styrkan av luminiscensen bör man då kunna avgöra makrocykelns position i rotaxanen. I framtiden hoppas vi kunna använda detta visualiseringsverktyg för att kunna börja använda rotaxaner som biosensorer för medicinsk diagnostik. / In rotaxanes, the movement of the macrocycle is usually tracked using 1H-NMR spectroscopy. The goal of this project is to instead develop systems so one can follow the macrocycle movement through luminescent lanthanide emission. This should be a powerful tool, as luminescence emission would allow for a direct visual readout of the macrocycle position along the thread with the naked eye. To allow luminescence in lanthanide-based systems, a sensitizing antenna molecule needs to be present in close proximity to the lanthanide. In this project, a lanthanide ligand was placed at the stoppered end of a [2]rotaxane, and a sensitizing antenna was attached to the threaded macrocycle. A change in pH induces the macrocycle to move closer to the lanthanide stopper, which causes the antenna to sensitize the lanthanide and start the luminescence emission. Based on the strength of the luminescence, one should then be able to determine the location of the macrocycle in the rotaxane. We hope to use this visual readout tool to eventually turn rotaxanes into useful point-of-care biosensors for medical diagnostics.
205

Etude par spectrométrie de masse à étincelles des lanthanides et autres éléments traces dans les carbonates filoniens : Alpes externes françaises .

Le Suave, Raymond 14 June 1974 (has links) (PDF)
Cette étude porte sur les relations pouvant exister entre les minéralisatîons alpines et les profils de répartition des lanthanides. Notre choix du matériau d'étude s'est porté sur les carbonates filoniens à cause des propriétés particulières qu'ils possèdent, tout d'abord leur omniprésence en tant ,que matériau des gangues tout au long des, Alpes externes françaises, ensuite la présence constante,mais variable en quantité,des lanthanides. Les moyens techniques mis à notre disposition au Centre d'Etudes Nucléaires de Grenoble ayant nécessité de notre part l'adaptation d'une méthode générale d'analyse physique au problème spécifique du dosage des éléments traces dans les carbonates, cet exposé laissera donc une placeau travail purement analytique, trop souvent délaissé
206

Nonlinear optical properties of nanostructures, photochromic and lanthanide complexes in solution / Propriétés optiques non linéaires de nanostructures, de complexes photochromes et de complexes de lanthanides en solution

Singh, Anu 11 December 2012 (has links)
L’Optique non linéaire est un outil très puissant pour étudier les propriétés des matériaux. Dans cette thèse, nous avons utilisé deux techniques d’optique non linéaire pour l’étude des non linéarités moléculaires: la génération de seconde harmonique induite sous champ électrique (EFISH) et la diffusion harmonique de la lumière (DHL). Tout d'abord, nous avons mis en évidence la conjugaison des groupements donneurs pi- dans les complexes d’iridium cyclométallés. Nous avons également exploré une série de molécules trinucléaires organométalliques (triaryle-1, 3, 5-triazinane-2, 4, 6-triones) fonctionnalisées par des acétylures métalliques avec des complexes des métaux de transition à leur périphérie- l’hyperpolarisabilité est beaucoup plus élevée que celles des dérivés purement organiques équivalents. D'autre part une série de complexes métalliques dipolaires et octupolaires contenant des ligands 2, 2-bipyridine photochromes à base de dithiényléthène (DTE) ont été synthétisés et caractérisés. L'étude révèle une forte augmentation de Les hyperpolarisabilités après irradiation UV correspondant à la fermeture de cycle associée au DTE. Cette forte exaltation reflète bien la délocalisation du système d’électrons pi- et la formation de chromophores push-pull dans les formes fermées. Troisièmement, nous avons étudié les propriétés optiques non linéaires de complexes de bis (phtalocyaninato) lanthanide (III) en sandwich, avec 2 phthalocyanines substituées en ABAB (alternance de donneurs d'électrons et d’accepteurs d'électrons), AB3 (3 groupes de donneurs), A4 (4 groupes d’accepteurs) et B4 (aucun groupe de donneur). L’hyperpolarisabilité du 1er ordre beta- mesurées sont les plus élevées jamais enregistrées pour des molécules octupolaires. La contribution directe d’électrons f dans les ions lanthanides complexés est également observée sur l'activité non linéaire du second ordre. Enfin, des nanosphères (AuNSs) et des nanotubes d'or (AuNRs) avec différents rapports d'aspect (AR) allant de 1,7 à 3,2 nm ont été synthétisés par la méthode de radiolyse. Le signal de deuxième harmonique émis par des AuNRs est nettement supérieur à celui des nanosphères et révèle leur dépendance à l'AR. Nous avons également mélangé un dérivé du chromophore 4-diméthylamino-N-méthyl-4-stilbazolium tosylate (DAST) avec les AuNRs et observé une influence des AuNRs sur l'amélioration des propriétés ONL du DAST. Une nette augmentation de l’hyperpolarisabilité (par un facteur 8) du derive de DAST en est la preuve. / Nonlinear optics is well known to be a highly powerful tool to investigate the properties of the materials. In this thesis we used two important nonlinear optical techniques known as Electric Field Induced Second Harmonic Generation (EFISH) and Harmonic Light Scattering (HLS) to study the first hyperpolarizability of various molecular objects. Firstly, we evidenced the pi donor conjugation in cyclometallated Ir complexes. We have also explored the series of trinuclear organometallic triaryl-1, 3, 5-triazinane-2, 4, 6-triones functionalized by d6-transition metal acetylides complexes at their periphery- large hyperpolarizabilities, far higher than those of related purely organic derivatives are reported. Secondly, a series of dipolar and octupolar dithienylethene (DTE)-containing 2, 2-bipyridine ligands with different metal ions featuring two, four and six photochromic dithienylethene units have been synthesized and fully characterized. The study reveals a large increase in the hyperpolarizability after UV irradiation and subsequent formation of ring-closed isomers. This efficient enhancement clearly reflects the delocalization of the pi-electron system and the formation of strong push&pull chromophores in the closed forms. Thirdly, we have investigated NLO properties of bis (phthalocyaninato) lanthanide-(III) double-decker complexes with crosswise ABAB (phthalocyanine bearing alternating electron-donor and electron-acceptor groups), AB3 (3 donor groups), A4 (4 donor groups) and B4 (no donor groups) ligands. First-order hyperpolarizability is measured and displays the highest quadratic hyperpolarizability ever reported for an octupolar molecule. The direct contribution of f-electrons in coordinated lanthanides ions is also observed on second order nonlinear activity. Finally, gold nanospheres (AuNSs) and gold nanorods (AuNRs) with different aspect ratios (AR) ranging from 1.7 to 3.2 nm have been synthesized by Radiolysis method. Second harmonic intensity collected from AuNRs is clearly higher than that of the nanospheres and reveals their dependence on the AR. We have also mixed the chromophore 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) derivative with AuNRs and observed the enhancement of DAST NLO properties in the presence of AuNRs. A clear increase in the hyperpolarizability (by a factor of 8) of DAST derivatives has been evidence.
207

Design, synthesis and characterization of neurotransmitter responsive probes for magnetic resonance and optical imaging / Conception, synthèse et caractérisation de sondes IRM et optiques sensibles aux neurotransmetteurs

Oukhatar, Fatima 21 December 2012 (has links)
Malgré le rôle primordial des neurotransmetteurs (NTs) dans le système nerveux central, leur détection non-invasive in vivo reste un défi majeur. L’imagerie par résonance magnétique (IRM), grâce à son excellente résolution spatiale et temporelle, est parmi les techniques de diagnostic les plus performantes. Elle est au centre des développements récents en imagerie moléculaire. En particulier, l’utilisation des agents d’imagerie intelligents qui sont capables de visualiser le statut physico-chimique des tissus commence à avoir une place importante en neuroscience.Cette étude a pour objectif de concevoir, synthétiser et caractériser in vitro des sondes intelligentes à base de cations lanthanide pour la détection in vivo des NTs. La conception de nos sondes est basée sur des interactions doubles avec des neurotransmetteurs zwitterioniques: d’une part entre le complexes de Ln3+ positivement chargé et le carboxylate du NT et d’autre part entre un ether couronne lié au complexe et la fonction amine du NT. Plusieurs des sondes synthétisées présentent des relaxivités élevées et ont une réponse relaxometrique remarquable aux NTs, bien que leur sélectivité vis-à-vis de l’ion bicarbonate ne soit pas suffisante. Afin de développer des sondes pour une approche bimodale IRM /optique, nous avons également intégré dans les complexes une benzophenone qui joue le rôle de chromophore pour sensibiliser la luminescence des ions Ln3+ émettant dans le proche infra-rouge. Le complexe d’Yb3+ correspondant a des propriétés de luminescence très intéressantes avec une forte réponse aux NTs. / In spite of the key role of neurotransmitters (NTs) in signal transduction, their non-invasive in vivo monitoring remains an important challenge. Magnetic resonance imaging (MRI) has recently been demonstrated as a promising technique to non-invasively visualize physiological events with excellent temporal and spatial resolution. In particular, smart MRI contrast agents that are able to report on the physico-chemical status of the tissues, start to have a strong impact in neuroscience. The objective of this work was the design, synthesis and in vitro characterization of a series of lanthanide-based probes responsive to NTs with the aim to track in vivo concentration changes of NTs using MR or optical imaging. The design of our imaging probes relies on a dual binding approach of zwitterionic NTs to the Ln3+ complexes, involving interactions (i) between a positively charged Ln3+ chelate and the carboxylate function of the NTs and (ii) between an azacrown ether appended on the chelate and the amine group of the neurotransmitters. Some of the novel contrast agents were found to exhibit high relaxivities and a remarkable relaxivity response towards NTs, though little selectivity against bicarbonate. In order to apply a bimodal MRI/optical imaging approach, we have also incorporated a benzophenone moiety into the chelate to sensitize the near-infrared emitting Ln3+ ions. The Yb3+ analogue proved to be highly sensitive to NTs.
208

Introdução aos métodos de determinação de estruturas por difração de raios-X em monocristais: aplicação a alguns complexos de lantanídeos e metais de transição com ligantes orgânicos / An introduction to the methodology of structure determination by single crystal x-ray diffraction: applications to some complexes of lanthanides and transition metals with organic ligands

Oliva, Glaucius 14 October 1983 (has links)
As estruturas cristalinas dos complexos Ln(ClO4)3.6[PONH2(C6H5)2] onde Ln=Eu, La, Cu[NH2(CH3)2CCO2]2, NiBr2.4[AsO(C6H5)3].8H2O (verde) e NiBr2.4[AsO(C6H5)3].1,5(CH3C6H5).H2O (alaranjado) bem como do ligante PONH2(C6H5)2 foram determinadas por difração de raios-X. Os complexos envolvendo íons lantanídeos refinaram a fatores R finais de R(Eu)=0,125, e R(La)=0,133 e foram encontradas a seguintes características principais: a) o sistema cristalino é cúbico; b) a coordenação do cátion é feita por seis átomos de oxigênio dos ligantes em configuração octaédrica (Eu) e antiprismática trigonal (La) com as terras raras em posições de alta simetria (23 para Eu e 3 para La); c) o restante das estruturas apresentam diferentes graus de desordem. À luz da sua configuração geométrica, a presença de uma forte banda 5Do-7F2 no espectro de fluorescência do complexo de Eu, proibida por considerações de simetria, é explicada como decorrente de acoplamentos vibrônicos. O desdobramento da linha υP=0 do espectro de infravermelho do coplxo de La é atribuído à presença de grupos P=0 não equivalentemente ligados a terra rara devido à desordem desta. O composto envolvendo o íon Cu(II) (fator R final 0,053) cristaliza no sistema monoclínico com os complexos se empacotando em camadas paralelas ao plano cristalino (100) com redes de pontes de H intracamada e com francas interações entre camadas consecutivas, o que explica o comportamento magnético quasi-bidimensional observado nestes cristais. O complexo de Ni(II) de coloração verde (fator R final 0,039) apresenta o íon metálico sobre um centro de simetria coordenado por seis moléculas de água numa conformação octaédrica distorcida, as quais estão ligadas aos grupos tfaso[AsO(C6H5)3] e íons brometo por fatores pontes de H. No complexo de coloração alaranjada (fator R final 0,087) o cátion está pentacoordenado com os quatro oxigênios dos ligantes tfaso formando a base de uma pirâmide quadrangular e um ânion Br- ocupando a quinta posição. Como uma conseqüência da resolução e refinamento da estrutura do complexo de Eu, a estrutura cristalina do ligante PONH2(C6H5) puro foi também determinada e refinada a um fator R de 0,033. / The crystal structure of the complexes Ln(ClO4)3.6[PONH2(C6H5)2] where Ln=Eu, La, Cu[NH2(CH3)2CCO2]2, NiBr2.4[AsO(C6H5)3].8H2O (green), NiBr2.4[AsO(C6H5)3.1,5(CH3C6H5).H2O (orange) and of the ligand PONH2(C6H5)2 have been determined by X-ray diffraction. The complexes involving lanthanide ions refined to final R factors of R(Eu)=0.125 and R(La)=0.133 and the following main features were found: a) the crystal system is cubic; b) the cation is coordinated to six ligand oxygens in octahedral earths on position of high symmetry (23 for Eu and 3 for La); c) the rest of the structures shows different degrees of disorder. In the light of the geometrical configuration, the occurrence of a strong band 5Do-7F2 in the fluorescence spectrum of the Eu complex, forbidden on symmetry grounds, is interpreted as a consequence of vibronic coupling. A splitting of the infrared υP=0 band in the La complex is attributed to the presence of P=0 goups non-equivalently bonded to the rare earth due to the disorder of this atom. The compound involving the Cu(II) ion (final R factor of 0.053) crystallizes in the monoclinic system with the complexes packed in layers parallel to the (100) crystal plane, with intralayer nets of H bonds and weak interactions between consecutive layers, which explains the quasi two-dimensional magnetic behavior observed in these crystals. In the green Ni(II) complex (final R=0.039), the metallic ion is sited on a center of symmetry and is octahedrally coordinated to six water molecules which are hydrogen bonded to the tfaso[AsO(C6H5)3] groups and the bromide ions. In the orange complex (final R=0.087) the cation is pentacoordinated with the four oxygens of the tpas ligands forming the basis of a quadrangular pyramid and one Br- anion in the fifth position. As a by product in the solution and refinement of the Eu complex structure, the crystal structure of the pure ligand PONH2(C6H5) was also determined and refined to a R-factor of 0.033.
209

Co-intégration de fonctions optiques et microfluidiques sur substrat de verre pour l'analyse en milieu hostile / Co-integration of optical and microfluidic functions on glass substrate for analysis in hostile environments

Jardinier, Elsa 06 December 2013 (has links)
La volonté actuelle de réduire les risques environnementaux et humains amène les chercheurs à trouver de nouvelles solutions de traitement-recyclage poussé des combustibles usés. Dans le but de réduire les volumes d’effluents qu’elle génère, ses temps de réponse et son coût, la miniaturisation de l’analyse chimique en ligne constitue l’un des principaux enjeux de ces recherches. Dans ce contexte, le présent manuscrit traite de la conception, du dimensionnement, de la fabrication et de la caractérisation d’un capteur spectrophotométrique intégré sur verre borosilicate, pour l’analyse des cations radioactifs. Le dispositif, nommé « guide à nanocanal », est réalisé à l’aide des techniques de gravure sèche par plasma et d’échange d’ions. Il contient un coeur ruban surmonté d’un canal de (100 ± 10) nm de profondeur et d’un coeur plan, et permet la propagation d’un mode hybride optimisant ainsi l’interaction fluide/onde guidée sur un large domaine de longueurs d’ondes. Des mesures spectrales d’une solution de nitrate de néodyme en milieu nitrique peu acide (pH 2) et un traitement statistique ont permis de démontrer une limite de détection minimale en terme de coefficient d’absorption de (3,7 ± 0,9) x 10-3 cm-1 sur une longueur de (3,70 ± 0,05) cm et un volume de seulement (7 ± 3) nL. Une structure permettant d’augmenter la longueur d’interaction et donc de diminuer la limite de détection est proposée en perspectives de ce travail, de même qu’une étude préliminaire pour l’utilisation du dispositif en milieu actif. / The current will of reducing environment and human hazards has led the scientists to imagine new solutions for nuclear waste reprocessing. Miniaturized online chemical analysis of industrial processes has in particular an important role to play to reduce effluent volumes, response times and costs. In this context, we present the design, fabrication and characterization of an integrated spectrophotometric sensor on glass for chemical analysis of radioactive cations. The device is called a ―nanochannel waveguide‖ and is fabricated by reactive ion etching and ion exchange on glass. It is made of two borosilicate glass wafers bonded together. The first one contains a strip core and the second one a (100 ±10) nm deep nanochannel and a slab core. It allows the propagation of a hybrid mode, optimizing the fluid/guide wave interaction on a large wavelength range. Spectrometric measurements of a neodymium nitrate in nitric acid (pH 2) followed by statistical treatment have led to a limit of detection in terms of absorption coefficient of (3.7 ± 0.9) x 10-3 cm-1 for a device length of (3.70 ± 0.05) cm and fluid volume as low as (7 ± 3) nL. A structure allowing to increase the interaction length and therefore further decrease the detection limit has been proposed as an outlook of this work, and a preliminary study for use in a nuclear environment has been performed.
210

p-Toluenossulfatos de terras raras hidratados: síntese, caracterização e estudo termoanalítico em diferentes atmosferas / Hydrated rare earth p-toluenesulfonates: synthesis, characterization and thermoanalytical study in different atmospheres

Santos, Arnaud Victor dos 18 September 1998 (has links)
Este trabalho consiste na investigação termoanalítica dos p-toluenossulfonatos de terras raras hidratados, abordando aspectos relativos à etapa de desidratação, decomposição térmica dos sais anidros e metodologia alternativa para obtenção de oxissulfetos. As reações entre o ácido p-toluenossulfônico e hidroxicarbonato de terras raras (III), em meio aquoso, conduziram a compostos de fórmula geral mínima TR(C7H7SO3)3.xH2O, sendo TR3+ = La ao Lu e Y com x variando de 2 a 7. Esta estequiometria foi estabelecida a partir dos resultados de análise elementar e termogravimetria. Os compostos foram caracterizados e, posteriormente, investigados termoanaliticamente. O estudo do comportamento térmico dos compostos foi realizado empregando a TG/DTG em atmosfera dinâmica de ar, N2, CO2, ar + CO2 e H2 + Ar a uma razão de aquecimento de 10°C min-1. A etapa de desidratação mostrou-se independente da atmosfera empregada. O processo de decomposição térmica do sal anidro em ar, CO2, ar + CO2 conduziu a formação de oxissulfatos com diferentes estequiometrias. Os resultados indicaram que a estabilidade térmica dos p-toluenossulfonatos anidros e dos oxissulfatos diminui com o raio do íon TR3+. O mesmo não ficou evidenciado quando se utilizou atmosfera de N2, uma vez que nenhum patamar indicativo de produtos intermediários e/ou finais termoestáveis foi formado. Os dados TG em atmosfera de H2 + Ar indicaram a formação de dioxissulfeto (TR2O2S). Isto foi confirmado pelo reaquecimento do produto em atmosfera de ar, que evidenciou ganho de massa característico da oxidação a oxissulfato. Os eventos térmicos foram evidenciados nas curvas DSC, por picos no sentido endotérmicos ou exotérmicos, e estão em concordância com as variações de massa indicadas nas curvas TG/DTG. Para alguns compostos foram determinados os parâmetros cinéticos, para etapa de desidratação, utilizando método dinâmico por TG/DTG e DSC. As curvas TG mostraram alguns eventos sobrepostos, evidenciando um processo de decomposição térmica aparentemente complexo, característico da saída de vários produtos voláteis simultaneamente. Neste caso, os experimentos utilizando o sistema simultâneo e acoplado TG/DTA-GC/MS possibilitou a detecção e análise destes voláteis. / This work consists in the thermoanalytical investigation of hydrated rare earth p-toluenesulfonates, considering the relative aspects of the dehydration step, thermal decomposition of the anhydrous salts and altemative methods for preparation of the oxysulfides. The compounds were prepared in aqueous solution, by reaction of p-toluenesulfonic acid and basic carbonates. The products of the reactions presented general formula TR(C7H7SO3)3.xH2O, TR3+ = La - Lu and Y, and x = 2 - 7. This stoichiometry was established through elemental analysis and TG data. The p-toluenesulfonates were characterized and investigated thermoanalytically. The study of the thermal behaviour of these compounds was accomplished using TG/DTG in air, N2, CO2, air + CO2 and H2 + Ar dynamic atmospheres with heating rate of 10 °C min-1. The dehydration step is independent of the atmosphere employed. The thermal decomposition processes of the anhydrous salts in air, CO2, air + CO2 lead to fonnation of oxysulfates with different stoichiometries. The results indicated that thermal stability of anhydrous salts and oxysulfates decreases with ionic TR3+ radii. The same was not evidenced in the N2 atmosphere plateaus indicative of thermally stables intermediate compounds were not observed. TG data in H2 + Ar atmosphere indicated the formation of dioxysulfide (TR2O2S). This product was heated in air atmosphere, showing gain of mass characteristic of oxidation to oxysulfate. The thermal events were evidenced in DSC curves by endothermic and exothermic peaks, and they are in agreement with the weight changes indicated in TG/DTG curves. For some compounds kinectic parameters were determined for the dehydration step, using TG/DTG and DSC dynamic methods. TG curves showed some overlaped events, evidencing complexes thermal decomposition processes with simultaneously evoluation of several volatile products. In these case, TG/DTG-GC/MS experiments were made for the detection of these volatile ones.

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