Thesis (Ph. D.)--Institute of Paper Chemistry, 1966. / Includes bibliographical references (p. 74-76).

Phenols are some of the most readily available and easily elaborated aromatic compounds, but the strength of the CAr-O bond hampers their conversion to highly sought CAr-N, CAr-S and CAr-C analogues. Attempts have therefore been made to establish new protocols for achieving such transformations by derivatising phenols with suitable CAr-O bond activating groups. In particular, investigations have focussed on the development of reactions with the potential to enable phenols to be conveniently converted to anilines. Towards this goal, the synthesis of O-aryl trihaloacetimidates was investigated with a view to probing their ability to rearrange to N-aryl trihaloacetamides via transition metal catalysis (Scheme 1). It was found that O-aryl trichloroacetimidates could be obtained from the base-catalysed reactions of phenols with trichloroacetonitrile, but only when electron-rich phenols were applied. In contrast, N-(4-methylphenyl)-O-aryl trifluoroacetimidates were generated in good yields from electron-rich and electron-poor phenols by their condensation with N-(4-methylphenyl)trifluoroacetimidoyl chloride. With these substrates in hand, a number of transition metal catalysts were screened for activity in the proposed rearrangement reactions, but the desired transformations were not achieved. As part of this screen, a novel mono-NHC palladium(II) precatalyst with the potential to be thermally activated was developed. Scheme 1 The proposed strategy for converting phenols to anilines. The hydroxide-catalysed rearrangement of O-aryl-N,N’-diisopropyl isoureas to N-aryl- N,N’-diisopropyl ureas was reported in 1983, but there have been no reported applications of this reaction to date. The reaction was therefore revisited with the intention of realising its unexplored synthetic potential. The reported hydroxide-catalysed rearrangement of O-phenyl-N,N’-diisopropyl isourea to N-phenyl-N,N’- diisopropyl urea was, however, discredited on the basis of 1H NMR and UV spectrometric analyses (Scheme 2). This isourea was instead, found to be converted to phenoxide and diisopropyl urea under the reported conditions. A detailed kinetic study revealed that the isourea was not directly hydrolysed, but underwent hydroxide-mediated elimination to produce phenoxide and diisopropyl carbodiimide. The hydrolysis of diisopropyl carbodiimide to diisopropyl urea then occurred in a slower, second step which was catalysed by hydroxide. Attempts to identify and synthesise N-heterocylcic isourea structures which were more disposed towards rearrangement were unsuccessful. Scheme 2 The reported and observed reactivity of O-phenyl-N,N’-diisopropyl isourea in aqueous base. Early attempts to use O-aryl-N,N’-dimethyl thiocarbamates as phenol-derived pseudohalides in palladium(0)-catalysed, CAr-C bond-forming cross-coupling reactions showed little promise due to the onset of their base-induced decomposition. However, the formation of a diaryl thioether side product was observed during these studies, leading to a preliminary investigation into the use of aryl thiocarbamates as hydrogen sulfide surrogates and thiophenol precursors in palladium(0)-catalysed C-S coupling reactions (Scheme 3). The promise of this approach was demonstrated by the synthesis of both symmetrical and unsymmetrical diaryl thioethers in the palladium(0)-catalysed couplings of O- and S-(4-trifluoromethyl)-N,N-dimethyl thiocarbamate with 1-bromo-4- fluorobenzene. Scheme 3 The preparation of diaryl thioethers from O-aryl thiocarbamates and aryl bromides via palladium(0) catalysis.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23939号 / 農博第2488号 / 新制||農||1089(附属図書館) / 学位論文||R4||N5374(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 渡邊 隆司, 教授 梅澤 俊明, 教授 森 直樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No description available.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1961. / Includes bibliographical references (p. 85-86).

Cette thèse s’inscrit dans une volonté d’adapter un procédé hydrothermal au traitement de la surface de fibres céramiques utilisées lors de la fabrication des composites à matrice céramique (CMCs). Le procédé conventionnel développé par la société Safran Ceramics se réalise en plusieurs étapes dont la principale consiste à dissoudre les phases oxydées de la surface des fibres Nicalon dans des bains d’acides. En conséquence, leurs propriétés chimiques de surface sont homogènes et un film de carbone microporeux est généré à la surface des fibres afin d’améliorer sa compatibilité chimique avec l’interphase de pyrocarbone qui y est déposée. Nous avons proposé de substituer ce procédé par un traitement par voie hydrothermale. En effet, l’eau possédant des propriétés physicochimiques ajustables en fonction des paramètres pression et température, il a été possible de modifier les propriétés de surface des fibres Nicalon d’une manière identique être productible au procédé conventionnel. L’efficacité et la compétitivité de ce traitement ont pu être démontrées par l’obtention de fibres avec des propriétés de surface optimales en une seule étape. Par la suite, l’étude du mécanisme réactionnel a révélé une attaque sélective des atomes de Si de la fibre selon des réactions d’hydrolyse. Puis, l’étude thermodynamique réalisée a mis en avant un régime à dominante cinétique. Finalement, les propriétés mécaniques des composites fabriqués à partir de tissus de fibres traités selon ce nouveau procédé ont été conformes aux objectifs. Ceci nous a donc permis de qualifier le traitement des fibres Nicalon par voie hydrothermale. / This thesis project was carried out in order to develop a hydrothermal processfor the surface treatment of ceramic fibres which are integrated into the fabrication of ceramicmatrix composites (CMCs). A conventional process was developed by Safran Ceramics tomodify the surface chemistry of the Nicalon fibres following 3 steps. The main step consistsin dissolving the oxidised phases at the fibre surface by the use of strong acids. As aconsequence, the chemical homogeneity of the surface is enhanced and a microporouscarbon film is generated helping its compatibilization with the pyrocarbon interphase that isdeposited in between the fibres and the matrix. It was suggested to substitute thisconventional process by a hydrothermal treatment. Indeed, as water displays tunablephysico-chemical properties regarding the temperature and pressure conditions, it waspossible to recover fibres demonstrating reproducible and similar characteristics. Theefficiency and competitivity of the hydrothermal treatment have been assessed throughoptimised surface properties obtained after one single step. Next, the mechanisminvestigation revealed a selective attack of the Si atoms contained in the fibre via hydrolysisreactions. Then, the thermodynamic study pointed out the fact that the process wasdominated by a kinetic regim. Finally, the mechanical caracterisation of the CMCs made ofhydrothermal treated fibres showed results which met all the requirements. These finalobservations allowed us to complete the qualification of the hydrothermal process to treat thesurface of Nicalon fibres.

La croissance mondiale, économique et industrielle, ainsi que la rapide progression démographique des populations, ont fait augmenter la demande en énergie fossile. Ces dernières années, beaucoup de recherches ont été orientées vers de nouvelles ressources énergétiques qui peuvent remplacer les carburants fossiles conventionnels. Les biocarburants sont des carburants écologiques renouvelables, obtenus grâce à la transformation des matières grasses animales et végétales. Ils sont classés en tant que ressource idéale, non-toxique et renouvelable, substituant avantageusement le Diesel conventionnel. Dans cette optique, nous nous sommes intéressés à la production des biocarburants à partir d’une source végétale, non alimentaire, très abondante dans le bassin méditerranéen, en l’occurrence le pistachier lentisque, par deux procédés, l’un est chimique appelé transestérification et l’autre est thermochimique, la solvolyse. Les caractérisations des biocarburants conformément aux normes en vigueur, ont montré que les propriétés physico-chimiques sont comparables à celles du Diesel conventionnel. Un moteur Diesel monocylindre refroidi à l'air, a été utilisé pour évaluer les caractéristiques de la combustion de ces biocarburants, à 1500 tr/min, sous diverses conditions de charges du moteur. Les caractéristiques de la combustion (pression du cylindre, délai d’auto-inflammation, taux de dégagement de chaleur et durée de combustion) des biocarburants obtenus, sont comparées à celles du Diesel conventionnel. / The world economic and industrial growths, as well as the demographic rapid progression, have increased the fossil energy demand. These last years, much of researches were directed towards new energy resources which can replace the conventional fossil fuels. The biofuels are renewable ecological fuels derived from biomass; they are classified as an ideal resource, non-toxic and renewable component with respect to the conventional Diesel. In this context, we were firstly interested to the production of the biofuels starting from a non-edible vegetable source widely available in the Mediterranean basin which is the Pistacia Lentiscus using two processes. The first one is a chemical method named “transesterification” and the second one is a thermochemical procedure called “solvolysis”. The biofuels physicochemical properties, measured via standard methods, are similar to those of Diesel fuel. A single cylinder, naturally aspirated DI Diesel engine is operated at 1500 rpm with either pure produced biofuels or their blends with Diesel fuel for several ratios (50, 30 and 5 v%) and engine load conditions. The combustion parameters, their blends are compared with those of Diesel fuel.

La demande mondiale des composites à fibres de carbone est en forte croissance. Les résidus qui en découlent augmentent également. Le procédé de solvolyse a été étudié pour recycler les fibres de carbone et valoriser la résine décomposée dans la phase liquide. L’étude se focalise sur l’impact du procédé batch (température et temps de réaction) sur la disparition de la résine dans l’eau sous- et supercritique. Le procédé batch n’est pas limité par la pénétration de l’eau dans un lit de composite, mais par contre, la haute teneur en composés organiques semble initier un phénomène de repolymérisation. Aux conditions optimales (350°C, 30 min et 400°C, 15 min) les fibres sont dépourvues de résine PA6, et les propriétés mécaniques sont proches des fibres vierges. Les analyses de diffraction des rayons X montrent une modification des distances inter-réticulaires des empilements de graphène, et la spectroscopie Raman met en évidence des modifications de la structure turbostratique des fibres. Ainsi le procédé de solvolyse a conduit à des changements nanostructuraux. Les valeurs de résistance à la traction sont assez proches de celles des fibres vierges. Ainsi, les fibres peuvent être réutilisées dans la reformulation de nouveaux composites. Enfin, l’étude cinétique basée sur les valeurs d’énergie d’activation en eau sous-critique (77,79 kJ/mol) et en eau supercritique (78,51 kJ/mol) montre qu’il s’agit du même schéma mécanistique régissant la réaction de dépolymérisation de la résine. La composition de la phase liquide montre la récupération de 70 % de monomère caprolactame et de la formation de produits plus lourds dans les temps de réaction relativement long (>45min). Ceci a été expliqué par un phénomène de repolymérisation. L’utilisation du CeO2 a permis d’une part de limiter des réactions indésirables et d’autres part d’améliorer la conversion de la résine PA6 en son monomère dans les temps de réaction courts. / The global demand of carbon fibers reinforced composites increases greatly, resulting in an increase of its residues. The solvolysis process has been studied in the framework of the recycling of carbon fibers and the recovery of the resin decomposed in the liquid phase. First, the study focuses on the impact of the batch process (temperature and reaction time) on the resin removal under subcritical and supercritical water. Although the batch process is not limited by the water diffusion into the composite bed, a large amount of organics results in a repolymerization phenomenon. The optimal conditions (350 °C, 30 min and 400 °C, 15 min) led to achieve the PA6 resin removal and the mechanical properties of recovered carbon fibers are similar to the virgin ones. The X-ray diffraction patterns show a modification of the inter-reticular distances of the graphene stacks, and Raman spectroscopy analysis reveal a modification in the turbostratic structure. Therefore nanostructural changes have occurred due to solvolysis process. Tensile strength values are quite similar to those of the virgin fibers, thus the fibers can be reused in the reformulation of new composites. Finally, the kinetic study based on the values of activation energy in subcritical water (77.79 kJ / mol) and in supercritical water (78.51 kJ / mol) shows that the same mechanistic scheme is governing the resin depolymerization reaction. The composition of the liquid phase shows the recovery of 70 % the monomer (caprolactam) and the production of heavier products in long reaction times (>45min). This has been explained by a repolymerization phenomenon. The use of CeO2 was efficient to limit undesirable reactions and to improve the conversion of the PA6 resin into its monomer in short reaction times.

Combined microwave assisted extraction/degradation of technical lignin in green solvents was successfully employed to generate polyphenolic oligomers with lower Mw than the starting material. For Lignoboost, the highest liquid yield (65 %) was obtained in 20 min at 160 °C using ethanol as solvent. This is an increase in ethanol soluble yield with 38 % compared to solvent extraction. The highest yield for Lignosulfonate was obtained with methanol as solvent, at 160 °C for 20 min. Obtained liquid fractions were analysed by SEC, FT-IR, DSC, TGA, 31P-NMR and 2D-HSQC NMR in order to explain the mechanism of the increased yield, and to study the structural changes after microwave extraction/degradation. 2D-NMR indicates cleavage of β-O-4 inter-unit linkages, but also that some modification around the bond could take place. Lignin based thermosets were synthesised employing the polyesterification between lignin, citric acid and poly(ethylene glycol) (PEG). It was concluded that introduction of PEG into the system was crucial for a homogenous thermoset synthesis with a high gel content. From TGA analysis it could be concluded that the thermoset based on original Lignoboost had a lower thermal stability than the counterparts prepared from lower molecular weight fractions. This implies that the esterification reaction between original Lignoboost and the other co-monomers is obstruct by sterically hindrance, which means that pre-conditioning is positive for the final material properties. / I denna studie utnyttjades en mikrovågsbaserad teknik, för att framgångsrikt extrahera och bryta ner lignin till polyfunktionella oligomerer med lägre molekylvikt än ursprungsmaterialet. Både lignin extraherat genom sulfat- och sulfitprocessen, d.v.s. kraft lignin (Lignoboost) och lignosulfonat, undersöktes. Det högsta lösliga utbytet för Lignoboost (67 %) kunde uppnås efter 20 min vid 160 °C genom att använda etanol som lösningsmedel, vilket är en ökning med 38 % jämfört med enbart extraktion i etanol. Under samma förhållanden uppnåddes även det högsta lösliga utbytet för Lignosulfonat, fast genom att använda metanol som lösningsmedel. De erhållna lösliga fraktionerna analyserades med hjälp av SEC, FT-IR, DSC, TGA, 31P-NMR samt 2D-HSQC NMR, med syftet att förklara ökning i lösligt utbyte samt studera eventuella strukturella förändringar efter bearbetning i mikrovågsugnen. Resultat från 2D-NMR indikerar på nedbrytning av β-O-4 bindningar, men även på att modifikationer kring bindningen kan ha uppkommit. Tvärbundna, ligninbaserade material syntetiserades genom att nyttja polykondensationsreaktionen mellan lignin, citronsyra och polyetylenglykol (PEG), vilket resulterade i esterbindningar. Det var möjligt att dra slutsatsen att introducering av PEG in i systemet var avgörande för att nå homogena material med hög andel tvärbindningar. Genom TGA analyser kunde det fastslås att tvärbundna material baserade obehandlad Lignoboost hade lägre termisk stabilitet än dess motsvarigheter baserade på fraktioner med lägre molekylvikt. Detta tyder på att esterreaktionen mellan obearbetad Lignoboost och de två andra monomererna försvåras genom steriskhindring, vilket innebär att bearbetning av ligninet medför positiva effekter på egenskaperna hos det slutgiltiga materialet.

<p> Techniques have been developed for making cryoscopic and vapour pressure measurements in anhydrous hydrogen fluoride. The cryoscopic constant for the solvent has been determined. </p> <p> The techniques developed have been used to determine the mode and extent of the ionization of some acids and bases of the HF system. The formation and stability of polymeric ions in the solvent has been investigated and the formation of the previously unknown anion As₂F₁₁⁻ has been shown. Cryoscopy has been used to detect a new polymeric 1:1 adduct of XeF₂ and SbF₅. Solutions of cyanides in HF have been investigated and the formation of a new polymeric cation Hg₂CN₃⁺, formed when mercury cyanide dissolves in HF, has been suggested. The results of some experiments on solvolysis reactions are also reported. </p> / Thesis / Doctor of Philosophy (PhD)