no / The formation of crystalline molecular complexes of benzoic acid and isonicotinamide with 1:1 and 2:1 compositions has been investigated through solution cocrystallization. The 1:1 complex was solely obtained from ethanol solutions, while either complex could be grown from aqueous and methanol solution by variation of the initial composition. The crystal structures of the 2:1 complex and a monohydrate of isonicotinamide were determined by single crystal X-ray diffraction. The intermolecular interactions in the crystal structure of the complex were compared with other published carboxylic acid:isonicotinamide molecular complexes, which highlights the robust nature of the acid · · · pyridine and acid · · · amide hydrogen bond, which exist in most cases. Complementary computational studies into the binding of pairs of these molecules by ab initio calculations were found to support the experimental observations and highlight the role of solvent in controlling the final crystalline form for multicomponent systems, through altering the hierarchy of intermolecular interactions.

O crescimento acelerado da população mundial e o consequente aumento da produção de bens de consumo tem impulsionado uma crise na disponibilidade de recursos naturais, principalmente os hídricos. Diante da escassez de recursos hídricos, processos de tratamento de efluentes industriais e domésticos que visam o descarte zero de líquido (ZLD - Zero Liquid Discharge) vêm sendo cada vez mais estudados. Atualmente, diversos processos têm sido empregados com este propósito. No entanto, ainda há a geração, juntamente com a água recuperada, de uma corrente composta por uma solução salina concentrada, cuja composição normalmente é constituída por diferentes tipos de sais inorgânicos. Uma das formas de alcançar o descarte zero de líquidos é por meio da implementação de um processo adicional de separação, sendo a cristalização evaporativa considerada viável para essa finalidade. O emprego deste processo é limitado ao controle das características morfológicas das partículas obtidas, visto que estas influenciam diretamente na efetividade de separação dos processos subsequentes à cristalização (filtração, centrifugação). Além disso, efluentes industriais são soluções complexas, e a utilização da cristalização envolve a presença de mais de um sal em solução (co-cristalização). Este processo é pouco investigado na literatura científica, logo, a determinação de condições de processos visando controlar a características destas partículas não é trivial. Neste trabalho, foram estudados o efeito da taxa de evaporação e da presença de sementes na morfologia, composição, tamanho e hábito de partículas de cloreto de sódio e sulfato de cálcio obtidas por co-cristalização evaporativa em bateladas. Os resultados serviram para a determinação de parâmetros de operação para a co-cristalização visando a obtenção de partículas com elevado tamanho médio e baixa dispersão de tamanhos. Taxas de evaporação elevadas favoreceram a obtenção de aglomerados de partículas. A presença de sulfato de cálcio em solução resultou em partículas maiores, menos polidispersas e com menor grau de aglomeração. Tal resultado foi considerado positivo, visto que, estas características são desejáveis para a separação dos cristais da solução mãe. Foi também observado que as sementes de hemihidrato atuam inibindo a aglomeração dos cristais de NaCl. O aumento da quantidade de sementes destes sais culminou na obtenção de partículas menos aglomeradas, porém houve um alargamento das distribuições de tamanho de partículas. Nos experimentos em que foram utilizadas sementes de ambos os sais, o mesmo efeito na aglomeração foi observado. Em todos os experimentos com semeadura de hemihidrato, foi observada a aglomeração deste sal com o NaCl, que foi intensificada com o aumento da taxa de evaporação e com o aumento da concentração de sementes. Foi identificada a possibilidade de recuperação de ambos os sais e obtenção - em determinadas condições - de mais de 90% do NaCl com até 99,50% de pureza. / The accelerated growth of the world population and the consequent increase in the production of consumer goods, has driven to a crisis in the availability of natural resources, especially water. Due to the scarcity of water resources, industrial and domestic wastewater treatment processes that aim the Zero Liquid Discharge (ZLD) have been increasingly studied. Nowadays, several processes have been used for this purpose. However, in all of them, there is still the generation of a brine composed of a concentrated salt solution, concomitantly with the recovered water, whose composition is normally constituted by different types of inorganic salts. One way to achieve the ZLD is through the implementation of an additional separation process, for which the evaporative crystallization is considered technically viable for this purpose. The use of this process is limited to the control of the morphological characteristics of the particles obtained, since this influences directly the separation effectiveness of the downstream processes to crystallization (filtration, centrifugation). Besides, industrial effluents are complex solutions and its crystallization involves the presence of more than one salt in solution (cocrystallization). This process is still not well investigated on scientific literature, thus, the determination of process conditions aiming to control the characteristics of these particles is not trivial. In this work, the effect of the evaporation rate and the presence of seeds on the morphology, composition, size and habit of sodium chloride and calcium sulfate particles obtained by batch evaporative co-crystallization were studied. The results were used to determine the operating parameters for the cocrystallization in order to obtain particles with high average size and narrow dispersion of sizes. High evaporation rates favored the obtaining of agglomerated particles. The presence of calcium sulfate in solution resulted in larger particles, less polydisperse and with less degree of agglomeration. Such result was considered positive, since, these characteristics are desirable for the separation of the crystals from the solution. Seeds of hemihydrate inhibited the agglomeration of the NaCl crystals. The increase in seed load of hemihydrate culminated in obtaining less agglomerated particles, but there was an increase in particle size distributions. In the experiments in which seeds of both salts were used, the same effect in the agglomeration was observed. In all experiments with seeds of hemihydrate, agglomeration of this salt with NaCl was observed, which was intensified with increasing evaporation rate and increasing seed amount. It was identified the possibility of recovery of both salts and, for certain conditions, obtaining more than 90% of NaCl with up to 99.50% purity.

Non-isothermal crystallization of the PET/PTT copolyesters was studied at five different cooling rates over 1-20oC/min by means of differential scanning calorimetry (DSC). Both the Ozawa equation and the modified Avrami equation have been used to analyze the crystallization kinetics. The non-isothermal kinetics of most copolymers cannot be described by the Ozawa analysis, except the copolyester with a composition of 66.3% trimethylene- (TT) and 33.7 %ethylene- terephthalates (ET). It may be due to the inaccuracy of the Ozawa assumptions, such as the secondary crystallization is neglected. From the kinetic analysis using the modified Avrami equation, the Avrami exponents, n, were found to be in the range of 2.43-4.67 that are dependent on the composition of the copolyesters. The results indicated that the primary crystallization of the PET/PTT copolymers followed a heterogeneous nucleation and a spherulitic growth mechanism during the non-isothermal crystallization. In the cases of the copolyesters with either TT or ET less than 10%, we found the molten temperature is a key factor to decide whether the Ozawa equation can be succeeded in analyzing the dynamic crystallization. For the non-isothermal crystallization, a single exothermic peak was detected in each DSC curve regardless of the composition and the cooling rate. It indicated that a single-mode distribution of the crystallite sizes was formed during the cooling process. After the non-isothermal crystallization, the melting behavior of the specimens was monitored by temperature modulated DSC (TMDSC) in the conventional mode and the modulated mode. Multiple endothermic peaks were observed in both modes. The wide-angle X-ray diffraction (WAXD) patterns of these copolymers showed that the peak height became sharper and sharper as the crystallization temperature increased, but the position of the diffraction peaks did not change apparently. It indicated that the multiple melting behaviors did not originate from the melting of the crystals with different structures. The melting behavior of these PET/PTT copolyesters can be explained logically by using the melt-recrystallization model. From the reversing and non-reversing signals of TMDSC, the melting-recrystallization-remelting phenomena were further verified. In addition, a small endothermic peak was found at the highest melting temperature in the reversing thermogram for TT-enriched copolyesters. It is reasonably to believe that this endotherm is attributed to the melting of the crystals that are formed in regime I during the heating scan. The cocrystallization of the PET/PTT copolyesters was studied using DSC and WAXD. A clear endothermic peak in the DSC thermogram was detected over the entire range of copolymer composition. A minimum melting temperature was found for the copolyester with 50% ET. The WAXD patterns of these copolymers can be divided into two groups with sharp diffraction peaks, i.e., PET type and PTT type crystals. The transition of crystal structure between PET type and PTT type occurred around the eutectic composition (50 % ET and TT), determined from the variation of the melting temperature with the composition. In addition, the fiber diagram and the WAXD pattern of the copolyester with the eutectic composition showed a different crystalline structure. These results indicated that the cocrystallization behavior of the PET/PTT copolyesters was isodimorphic.

O crescimento acelerado da população mundial e o consequente aumento da produção de bens de consumo tem impulsionado uma crise na disponibilidade de recursos naturais, principalmente os hídricos. Diante da escassez de recursos hídricos, processos de tratamento de efluentes industriais e domésticos que visam o descarte zero de líquido (ZLD - Zero Liquid Discharge) vêm sendo cada vez mais estudados. Atualmente, diversos processos têm sido empregados com este propósito. No entanto, ainda há a geração, juntamente com a água recuperada, de uma corrente composta por uma solução salina concentrada, cuja composição normalmente é constituída por diferentes tipos de sais inorgânicos. Uma das formas de alcançar o descarte zero de líquidos é por meio da implementação de um processo adicional de separação, sendo a cristalização evaporativa considerada viável para essa finalidade. O emprego deste processo é limitado ao controle das características morfológicas das partículas obtidas, visto que estas influenciam diretamente na efetividade de separação dos processos subsequentes à cristalização (filtração, centrifugação). Além disso, efluentes industriais são soluções complexas, e a utilização da cristalização envolve a presença de mais de um sal em solução (co-cristalização). Este processo é pouco investigado na literatura científica, logo, a determinação de condições de processos visando controlar a características destas partículas não é trivial. Neste trabalho, foram estudados o efeito da taxa de evaporação e da presença de sementes na morfologia, composição, tamanho e hábito de partículas de cloreto de sódio e sulfato de cálcio obtidas por co-cristalização evaporativa em bateladas. Os resultados serviram para a determinação de parâmetros de operação para a co-cristalização visando a obtenção de partículas com elevado tamanho médio e baixa dispersão de tamanhos. Taxas de evaporação elevadas favoreceram a obtenção de aglomerados de partículas. A presença de sulfato de cálcio em solução resultou em partículas maiores, menos polidispersas e com menor grau de aglomeração. Tal resultado foi considerado positivo, visto que, estas características são desejáveis para a separação dos cristais da solução mãe. Foi também observado que as sementes de hemihidrato atuam inibindo a aglomeração dos cristais de NaCl. O aumento da quantidade de sementes destes sais culminou na obtenção de partículas menos aglomeradas, porém houve um alargamento das distribuições de tamanho de partículas. Nos experimentos em que foram utilizadas sementes de ambos os sais, o mesmo efeito na aglomeração foi observado. Em todos os experimentos com semeadura de hemihidrato, foi observada a aglomeração deste sal com o NaCl, que foi intensificada com o aumento da taxa de evaporação e com o aumento da concentração de sementes. Foi identificada a possibilidade de recuperação de ambos os sais e obtenção - em determinadas condições - de mais de 90% do NaCl com até 99,50% de pureza. / The accelerated growth of the world population and the consequent increase in the production of consumer goods, has driven to a crisis in the availability of natural resources, especially water. Due to the scarcity of water resources, industrial and domestic wastewater treatment processes that aim the Zero Liquid Discharge (ZLD) have been increasingly studied. Nowadays, several processes have been used for this purpose. However, in all of them, there is still the generation of a brine composed of a concentrated salt solution, concomitantly with the recovered water, whose composition is normally constituted by different types of inorganic salts. One way to achieve the ZLD is through the implementation of an additional separation process, for which the evaporative crystallization is considered technically viable for this purpose. The use of this process is limited to the control of the morphological characteristics of the particles obtained, since this influences directly the separation effectiveness of the downstream processes to crystallization (filtration, centrifugation). Besides, industrial effluents are complex solutions and its crystallization involves the presence of more than one salt in solution (cocrystallization). This process is still not well investigated on scientific literature, thus, the determination of process conditions aiming to control the characteristics of these particles is not trivial. In this work, the effect of the evaporation rate and the presence of seeds on the morphology, composition, size and habit of sodium chloride and calcium sulfate particles obtained by batch evaporative co-crystallization were studied. The results were used to determine the operating parameters for the cocrystallization in order to obtain particles with high average size and narrow dispersion of sizes. High evaporation rates favored the obtaining of agglomerated particles. The presence of calcium sulfate in solution resulted in larger particles, less polydisperse and with less degree of agglomeration. Such result was considered positive, since, these characteristics are desirable for the separation of the crystals from the solution. Seeds of hemihydrate inhibited the agglomeration of the NaCl crystals. The increase in seed load of hemihydrate culminated in obtaining less agglomerated particles, but there was an increase in particle size distributions. In the experiments in which seeds of both salts were used, the same effect in the agglomeration was observed. In all experiments with seeds of hemihydrate, agglomeration of this salt with NaCl was observed, which was intensified with increasing evaporation rate and increasing seed amount. It was identified the possibility of recovery of both salts and, for certain conditions, obtaining more than 90% of NaCl with up to 99.50% purity.

Yes / Solid state shear milling (S3M) is reported as a scalable, continuous, polymer-assisted cocrystallization technique. A specially designed milling pan was employed to provide high levels of applied shear, and the addition of a polymeric processing aid enabled generation of high stress fields. Carbamazepine–salicylic acid cocrystals were produced with 5–25 wt % of poly(ethylene oxide) (PEO). A systematic study was carried out to understand the effect of process variables on properties and performance of the cocrystals. S3M offers an important new route for continuous manufacturing of pharmaceutical cocrystals.

Le polyéthylène à ultra haute masse molaire (UHMWPE) présente une viscosité si forte à l’état fondu que seuls des procédés de mise en forme de type frittage peuvent être employé. Ce procédé rarement utilisé pour les polymères reste peu étudié. En particulier les deux principaux mécanismes généralement mentionnés que sont le réenchevêtrement et la cocristallisation aux interfaces sont difficilement observables séparément. Le UHMWPE, grâce à sa très haute viscosité à l’état fondu et grâce à son plateau caoutchoutique extrêmement étendue en température, peut faire l’objet d’essais mécaniques à la fois à l’état semi-cristallin et à l’état fondu. Des poudres natives de UHMWPE de masses molaires comprises entre 0,6 et 10,5 Mg.mol-1 sont utilisées comme matériau de départ pour leur mise en oeuvre par frittage. La consolidation des interfaces par soudage des particules a été effectuée sous pression à différentes températures supérieures au point de fusion et pour différentes durées. Des expériences de traction effectuées soit à température ambiante soit au-dessus du point de fusion ont permis de distinguer le rôle de l'interdiffusion des chaînes au travers des interfaces de celle de la cocristallisation dans les mécanismes de soudage de particules. Il s'est avéré qu’un soudage efficace se produit dans une échelle de temps très courte. La très faible influence de la durée de frittage par rapport à celle de la température de frittage a prouvé que l'interdiffusion des chaînes n'est pas régie par un mécanisme de reptation. L'explosion à la fusion des cristaux « hors-équilibre » de la poudre native est suggérée être le mécanisme principal permettant un réenchevêtrement dans un laps de temps beaucoup plus court que celui de la reptation. La cocristallisation est un phénomène si efficace dans la consolidation de l'interface à l'état solide qu'elle masque significativement la cinétique de réenchevêtrement gouverné par la température, visible dans les tests mécaniques à l’état fondu. / One of the main issues of ultra-high-molecular-weight polyethylene (UHMWPE) is to overcome its very high viscosity. Powder sintering is then often required instead of injection or extrusion. However, sintering mechanisms remain partially understood. Indeed, the two main mechanisms generally mentioned for interparticle welding, i.e. re-entanglement and cocrystallization, can hardly be observed separately. Fortunately, due to its very high molecular weight, UHMWPE exhibits an exceptionally broad rubbery plateau so that mechanical tensile tests can be easily performed both below and above the melting point. Four UHMWPE of molecular weight in the range of 0.6.106 g.mol-1 to 10.5.106 g.mol-1 have been processed by means of sintering of nascent powders. The interface consolidation or particle welding was carried out under pressure at various temperatures above the melting point and for various durations. Tensile drawing experiments performed either at room temperature or above the melting point enabled to discriminate the role of chain interdiffusion through the particle interface from that of cocrystallization in the mechanism of particle welding. It turned out that an efficient welding occurred within a very short time scale. The very weak influence of sintering time compared to that of sintering temperature gave evidence that chain interdiffusion was not governed by a reptation mechanism. The entropy-driven melting explosion of the “non-equilibrium” crystals in the nascent powder is suggested to be the main mechanism of the fast chain reentanglement and subsequent particle welding within a time scale much shorter than the reptation time. Cocrystallization is so much efficient in the interface consolidation in the solid state that it significantly hides the temperature-governed kinetics.

No / Crystal structure prediction simulations were carried out to explore the solid state packing alternatives of two diastereomeric salts consisting of a chlorine-substituted cyclic phosphoric acid and the two enantiomers of ephedrine. The experimentally observed crystal structures were correctly simulated with an error of a few kcal/mol. This represents a significant achievement in crystal structure prediction due to the complexity of the mathematical search problem at hand (two distinct molecules in the asymmetric unit, one of which is flexible) and due to the complex energetics of these organic salts. In principle, these simulations show the way toward a truly predictive model for racemate resolution by preferential crystallization of diastereomeric salts.

L’aromaticité et l’antiaromaticité demeurent un sujet d’actualité au niveau fondamental puisque ces concepts permettent d’expliquer la réactivité de diverses classes de molécules. Certains composés polycycliques ayant une conjugaison π étendue, comme par exemple les tétraoxa[8]circulènes, ont des cycles aromatiques et antiaromatiques qui affectent leurs propriétés physicochimiques. Les oxacirculènes sont formés d’un anneau de quatre furanes et de quatre benzènes positionnés en alternance et créant un cœur formellement antiaromatique de cyclooctatétraène (COT). Malgré cela, ces composés démontrent une grande stabilité et peuvent servir en tant que composantes de dispositifs optoélectroniques comme des diodes électroluminescentes. Les propriétés optoélectroniques de ces composés et leur organisation moléculaire à l’état solide sont à l’origine d’un comportement unique. Le présent mémoire décrit la synthèse de tétraoxa[8]circulènes par une réaction très spéciale de cyclocondensation de 1,4-quinones catalysée par des acides, permettant d’accéder à des grandes molécules conjuguées en une étape. Les composés synthétisés ont une géométrie qui empêche leur empilement efficace et crée des vides dans la structure cristalline pouvant servir à l’inclusion de molécules invitées. En particulier, l’inclusion de C60 effectuée par cocristallisation cause l’uniformisation des longueurs des liens du cœur COT des oxacirculènes, suggérant des interactions de transfert de charge. Enfin, les propriétés optiques étudiées par spectroscopie UV-vis et par fluorescence indiquent que les oxacirculènes sont sensibles à leur environnement moléculaire et pourraient donc être utilisés comme des senseurs chimiques. / Aromaticity and antiaromaticity remain important topics of chemical research because these concepts explain the reactivity of various classes of molecules. For instance, certain polycyclic compounds with π-extended conjugation, such as tetraoxa[8]circulenes, contain both aromatic and antiaromatic rings, which affect their physicochemical properties. Oxacirculenes consist of a circular arrangement of four furan and four benzene rings positioned in an alternating fashion, thus creating a formally antiaromatic cyclooctatetraene (COT) core. Despite this, oxacirculenes exhibit great stability. They can serve as components in optoelectronic devices such as electroluminescent diodes, and their molecular organisation in the solid state can be controlled in ways that influence their properties. The present memoir describes the synthesis of tetraoxa[8]circulenes by a very special acid-catalysed cyclocondensation reaction starting from suitable 1,4-quinones, thereby allowing the preparation of large conjugated molecules in a single step. The compounds prepared have an awkward molecular structure that inhibits efficient packing and creates voids in the crystal structure, allowing the inclusion of guests. In particular, the inclusion of C60, achieved by cocrystallization, appears to create charge-transfer interactions as indicated by uniformization of bond lengths in the COT core. Optical properties studied by UV-vis spectroscopy and fluorescence show that oxacirculenes are sensitive to their local chemical environment, suggesting that they can be used as chemical sensors for the rapid detection of guests.