Orientador: Maria Alvina Krähenbühl / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T13:18:26Z (GMT). No. of bitstreams: 1 Pinto_RafaelaRocha_M.pdf: 1796419 bytes, checksum: 6a9da7357c387302b7688841d36db606 (MD5) Previous issue date: 2011 / Resumo: Nos últimos anos tem aumentado o interesse em combustíveis oriundos de fontes renováveis como é o caso do biodiesel. Tendo em vista que os ácidos graxos são componentes de óleos e gorduras, usados para a produção do biodiesel em reações de transesterificação, e cujas propriedades ainda são bastante escassas na literatura, o objetivo do presente trabalho foi o de contribuir com dados experimentais de capacidade calorífica (cp) de ácidos graxos, constituintes de óleos e gorduras. Tais dados são necessários para os balanços de energia e para o projeto de equipamentos visando a purificação de óleos, bem como para o cálculo de reações químicas. A análise térmica diferencial é uma técnica dinâmica que vem sendo muito utilizada na determinação de dados térmicos, como capacidade calorífica, temperaturas de mudanças de estado, determinação da pureza de substâncias, entre outras. O cp é a medida da quantidade de energia necessária por unidade de massa (ou mol) de uma substância para elevar sua temperatura em um grau. Neste trabalho foram determinados os dados de cp dos seguintes ácidos graxos em fase líquida e pressão ambiente: ácido caprílico (C8:0), ácido cáprico (C10:0), ácido láurico (C12:0), ácido mirístico (C14:0), ácido palmítico (C16:0), ácido esteárico (C18:0), ácido oléico (C18:1) e ácido linoléico (C18:2). Para determinar a capacidade calorífica dos ácidos graxos, foi utilizado o Calorímetro Exploratório Diferencial - DSC da TA Instruments. Os dados experimentais foram processados pelo método do software Thermal Specialty Library versão 2.2 e pelo método da Amplitude. Os resultados mostraram que a capacidade calorífica aumenta com a temperatura e com o tamanho da cadeia carbônica. Entre os métodos avaliados não houve diferença entre os resultados obtidos. Os dados experimentais foram comparados com dados obtidos pelo método de contribuição de grupos e os desvios relativos chegaram a 15 %. O intervalo de temperatura de exploração foi de 308 K (35 ºC) a 573 K (300 ºC) / Abstract: In recent years the interest in renewable sources of fuels such as biodiesel has been increasing. Considering that fatty acids are components of fats and oils, used in the production of biodiesel in the transesterification reactions, and whose properties are still quite scarce in the literature, the purpose of this study was to contribute with experimental data of heat capacity (cp) of fatty acid constituents of oils and fats. Such data are needed for energy balances, for the design of equipment aimed at purification of oils and also for the calculation of chemical reactions. Differential thermal analysis is a dynamic technique that has been widely used in the determination of thermal data such as heat capacity, purity determination, phase change temperatures and others. The cp is the amount of energy required per unit mass (or mole) of a substance to raise its temperature by one degree. The cp were determined, in liquid phase and at atmospheric pressure, of the following fatty acids: caprylic acid (C8:0), capric acid (C10:0), lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2). To determine the heat capacities of the fatty acids, a Differential Scanning Calorimeter - DSC, of TA Instruments, was used. The experimental data were processed using the Thermal Specialty Library (version 2.2) software and the method of vertical displacement. The results showed that the heat capacity increased with temperature and with the length of the alkyl chains. A comparison of the two methods showed no difference between the resulting information, and when the data from the experiments were compared with the data obtained from the group contribution method, there was a relative deviation of 15%. The working temperature range was from 308 K (35 ºC) to 573 K (300 ºC) / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

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Rostlinné oleje se používají v mnoha odvětvích chemického průmyslu. V průběhu zpracování konkrétního produktu, ve kterém jsou rostlinné oleje použity, dochází často ke zvyšování teploty. Vyšší teplota urychluje průběh auto-oxidace což negativně ovlivňuje stabilitu olejů nebo výrobků z nich připravených. Mezidruhové mísení olejů je poměrně častým jevem jak při samotné výrobě tak i ve finálním výrobku. Cílem této práce bylo stanovit termo-oxidační stabilitu šesti čistých rostlinných olejů a jejich binárních směsí. První část práce zkoumá oleje a připravené směsi pomocí metody diferenciální kompenzační kalorimetrie. Tato metoda umožnila pochopení vztahů mezi termo-oxidačním chováním olejů a jejich směsmi pomocí stanovení teplot degradace. Přímá souvislost mezi obsahem mastných kyselin a stabilitou byla prokázána pouze zčásti, stejně tak jako původní předpoklad, že přídavek stabilnějšího olej zvýší stabilitu oleje méně stabilního. V několika případech docházelo dokonce ke snížení stability pod teplotu degradace obou čistých olejů. Ve druhé části byl zjišťován mechanismus pro-oxidační fáze vedoucí k degradaci olejů pomocí termogravimetrie, která ukázala přírůstek hmotnosti ve vzorcích oleje způsobeného absorpcí kyslíku a tvorbou peroxidů předcházející degradaci. V tomto případě již bylo možné pozorovat jistou souvislost mezi obsahem mastných kyselin a vzrůstem hmotnosti, pouze však jen pro čisté oleje. Ani v tomto případě nebyla prokázána aditivita vlastností způsobujících stabilitu směsí rostlinných olejů.

Solubility is the amount of solute in the solvent system at phase equilibrium with certain temperature and pressure. Many of the new chemical entities are lipophilic molecules that require techniques to enhance solubility. Solubility enhancement can be achieved by either physical and/or chemical modification of the drug. Various techniques are available for solubility enhancement of poorly soluble drugs include particle size reduction, salt formation, solid dispersions, use of surfactants, prodrug, crystal modification, etc. In this study, the three model drugs belong to BCS class II and IV having low solubility with a certain range of physicochemical properties were studies in solubility enhancement using fusion method, co-precipitation, nano-milling and spray drying techniques. The two different polymers employed for solubility enhancement are PEG 8000 and PVP 40,000. Solubility was determined by Shake Flask method at the temperature of 37±0.1 °C. The objective is to investigate the enhancement of solubility of the three model drugs namely Glipizide, Carvedilol and Furosemide in 1:1, 1:5 and 1:10 drug-polymer ratios and are characterized by Differential Scanning Calorimetry (DSC). The Solubility of Glipizide was enhanced from 11.18 ± 1.78 µg/ml to 35.73 ± 0.04 µg/ml by 219 % increase with nano-milling technique at 1:5 ratio with PEG 8000 as carrier whereas with PVP 40000 as carrier, 286 % increase in solubility to 43.26 ± 7.87 µg/ml was observed at 1:1 ratio by fusion method. The solubility of Carvedilol was enhanced from 5.04 ± 0.55 µg/ml to 17.51 ± 0.94 µg/ml by 246 % at 1:5 ratio by fusion method with PEG8000 as carrier and 2924 % enhancement in solubility to 152.70 ± 9.09 µg/ml at 1:10 ratio by nano-milling with PVP40000 as the carrier. Furosemide showed an increase in solubility from 55.94 ± 2.48 µg/ml to 164.11 ± 9.18 µg/ml by 193 % at 1:10 ratio by nano-milling technique with PEG8000 as carrier whereas with PVP40000 as carrier, 444 % increase was observed at 1:1 ratio by nano-milling technique with solubility of 304.52 ± 23.11 µg/ml. The data showed that the decrease in percentage crystallinity and enthalpy of fusion of the model drugs upon implementing solubility enhancement techniques with the effect of particle size and the carrier used resulted in the increase of aqueous solubility of the model drugs.

The cuticle is constituted of the biopolymer cutin and intra- and epicuticular waxes. In some cases, it has epicuticular wax crystals, protruding from the epicuticular wax film. One of the most important tasks is protection against desiccation. Many investigations were conducted to find the transport limiting component of the cuticle. It is evidentially confirmed that the waxes form this barrier. These waxes are multifactorial blends made of very-long-chain aliphatic (VLCA) compounds and triterpenoids (TRP). The VLCAs were proposed to constitute the transpiration barrier to water. However, experimental confirmation was lacking so far. The present study focuses on the development of a method to selectively extract TRPs from the cuticle and the impact of the removal on the transpiration barrier. The plants deployed in this study exhibited several features. They had no epicuticular crystals on their surfaces, were astomatous, had a rather durable and possibly isolatable cuticle. A broad range of wax compositions was covered from plants with no TRP content and low wax load like Hedera helix and Zamioculcas zamiifolia to plants with high TRP content and high wax load like Nerium oleander. The selective extraction was conducted using a sequence of solvents. TRPs were extracted almost exhaustively from CMs with the first MeOH extract. Only a minor amount of shorter chained VLCAs was obtained. The remaining waxes, consisting mostly of VLCAs and some remnant TRPs, were removed with the following TCM extract. After the extractions, the water permeance of native cuticular membranes (CM), MeOH extracted (M) and dewaxed cuticular discs (MX) was investigated gravimetrically. Compared to the water permeance of CMs, Ms showed no or only a small increase in water conductance. MXs, however, always showed strongly increased values. The knowledge about the wax compounds constituting the transport-limiting properties is vital for different projects. For various issues, it would be favourable to have a standardized wax mixture as an initial point of research. It could be used to develop screening procedures to investigate the impact of adjuvants on cuticular waxes or the influence of wax constituents on the properties of cuticular waxes. This work concentrated on the development of an artificial wax mixture, which mimics the physical properties of a plant leaf wax sufficiently. As target wax, the leaf wax of Schefflera elegantissima was chosen. The wax of this plant species consisted almost exclusively of VLCAs, had a rather simple composition regarding compound classes and chain length distribution and CMs could be isolated. Artificial binary, ternary and quaternary waxes corresponding to the conditions within the plant wax were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD) techniques and Fourier-transform infrared (FTIR) spectroscopy. Phase diagrams were mapped out for a series of binary, ternary and quaternary wax mixtures. FTIR experiments were conducted using, ternary and a quaternary artificial wax blends. The blends were chosen to represent the conditions within the wax of the adaxial CM plant wax. The FTIR experiments exhibited an increasing resemblance of the artificial wax to the plant wax (adaxial CM wax) with an increasing number of compounds in the artificial wax. The same trend was found for DSC thermograms. Thermograms of ternary and quaternary blends exhibited more overlapping peaks and occurred in a temperature range more similar to the range of the whole leaf plant wax. The XRD spectrum at room temperature showed good conformity with the quaternary blend. The current work illustrates a method for selective extraction of TRPs from isolated CMs. It gives direct experimental proof of the association of the water permeance barrier with the VLCA rather than to the TRPs. Furthermore, the possibility to mimic cuticular waxes using commercially available wax compounds is investigated. The results show promising feasibility for its viability, enabling it to perform as a standardized initial point for further research (e.g. to examine the influence of different constituents on waxes), revealing valuable knowledge about the structure and the chemistry-function relationship of cuticular waxes. / Die Kutikula ist eine der vielen Anpassungen, die Pflanzen entwickelten um nach der Besiedelung des Landes mit den Herausforderungen ihrer neuen Umgebung fertig zu werden. Sie überzieht überirdische Pflanzenorgane, wie Blüten oder Blätter und erfüllt verschiedene Aufgaben. Hierzu besteht sie aus dem biopolymer Kutin und intra- sowie epikutikulären Wachs. Studien, die sich mit der Lokalisierung der transporteinschänkenden Barriere beschäftigten, zeigten, dass die Wachse sie bilden. Diese sind vielschichtige Mischungen aus langkettigen aliphatischen Verbindungen (VLCA) und pentazyklischen Verbindung wie Triterpenen (TRP). Es wird davon ausgegangen, dass VLCAs die Barriere aufbauen, ein direkter experimenteller Nachweis dafür wurde jedoch noch nicht erbracht. In dieser Arbeit wurde daher ein Verfahren zur selektiven Extraktion von TRPs aus isolierten kutikulären Membranen (CM) entwickelt und deren Auswirkung auf die Transpirationsbarriere untersucht. Die untersuchten Pflanzen wiesen keine epikutikuläre Kristalle auf, hatten keine Stomata auf der Kutikula der Blattoberseite und es war möglich ihre Kutikula zu isolieren. Die Zusammensetzung der Wachse variierte von wenig Wachs ohne TRPs (z. B. Hedera helix, Zamioculcas zamiifolia) hin zu pflanzen mit großer Wachsmenge und hohem TRP- Anteil (Nerium oleander). Die selektive Extraktion wurde durch die sequenzielle Nutzung zweier Lösemittel erreicht. TRPs wurden fast vollständig mit Methanol (MeOH) entfernt, während VLCAs überwiegend nur mit Chloroform (TCM) extrahiert werden konnten. Die gravimetrische Bestimmung der Wassertranspiration von unbehandelten, mit Methanol extrahierten (M) und entwachsten Membranen (MX) in Transpirationskammern zeigte bei allen untersuchten Pflanzenarten einen einheitlichen Trend auf. Im Vergleich zu CMs erhöhte sich die Transpirationsrate bei Ms nicht oder nur geringfügig, während bei MXs ein starker Anstieg festgestellt werden konnte. Diese Ergebnisse stellen den ersten direkten experimentellen Nachweis der Verbindung von VLCAs zur Transpirationsbarriere kutikulärer Wachse dar. Mit dem Wissen, sich bei der Untersuchung der Permeation durch die Kutikula sich nur auf die VLCA Fraktion beschränken zu müssen können weitere Projekte effizient angegangen werden. Ein leicht erhältliches Standartwachsgemisch könnte Ausgangspunkt für die Untersuchung des Einflusses verschiedener Pflanzenwachskomponenten auf deren physikalische Eigenschaften dienen. Als Zielwachs diente das Blattwachs von Schefflera elegantissima. Es bestand fast ausschließlich aus VLCAs, hatte eine recht einfache Zusammensetzung bezüglich der Stoffklassen und Kettenlängenverteilung und die Kutikula war isolierbar. Mit Hilfe von dynamische Differentialkalorimetrie (DSC), Röntgenbeugung (XRD) und Fouriertransformierter Infrarot (FTIR) Spektroskopie wurden binäre, ternäre und quaternäre Gemische, die Verhältnisse im Pflanzenwachs wiederspiegelten, untersucht und Phasendiagramme erstellt. Phasendiagramme wurden von einer Reihe der binären Gemische, bestehend aus Alkanen oder Alkoholen, ternären Gemischen aus zwei Alkanen und einem Alkohol und quaternären Gemischen aus zwei Alkanen und zwei Alkoholen erstellt. FTIR-spektroskopische Versuche zeigten mit zunehmender Komponentenzahl eine erhöhte Ähnlichkeit der artifiziellen Wachse zum Pflanzenwachs (adaxiale isolierte Kutikula). Ein ähnlicher Trend wurde für die Ähnlichkeit der Thermogramme der artifiziellen Gemische zum Pflanzenwachs (aus dem Extrakt ganzer Blätter) ersichtlich. Das Diffraktogramm des quaternären Waches stimmte auf Raumtemperatur gut mit dem des Pflanzenwachses (adaxiale isolierte Kutikula) ein. Diese Arbeit beschreibt eine Methode zur selektiven Extraktion von TRPs aus isolierten kutikulären Membranen. Sie zeigt einen direkten experimentellen Nachweis für die Assoziation der Transpirationsbarriere zu den VLCAs und nicht zu den TRPs. Zusätzlich wird die Möglichkeit kutikulare Wachse mit Hilfe von kommerziell erhältlichen Wachskomponenten nachzustellen untersucht, was vielversprechende Ergebnisse liefert. Dieses Wachs könnte daher als standardisierter Ausgangspunkt für weitere Experimente (z. B. zur Untersuchung des Einflusses verschiedener Wachskomponenten auf dessen physikalische Eigenschaften) dienen. Dies könnte wertvolle Informationen über die Struktur und die Beziehung zwischen chemischer Zusammensetzung und der Funktion kutikulärer Wachse liefern.

The thermotropic behavior of multilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC), or of DPPC in admixture with cardiolipin or cholesterol, in the presence of various N-alkyl derivatives of both adriamycin-14-valerate has been investigated by high sensitivity differential scanning calorimetry. The analogues, particularly the 14-valerate derivatives, which were most lipophilic as judged by their lipid/buffer, and to a lesser extent by their octanol/buffer, partition coefficients, were the most effective in depressing the tm of the investigated lipids; correlations, however, were not absolute. Other factors, such as the distribution of the drugs between the solid and liquid-crystalline phases of the bilayer, were also important to the observed membrane perturbations. With all anthracyclines, however, no major changes in the transition enthalpy were observed. In the case of vesicles prepared from pure DPPC, curve fitting analysis based on ideal solution theory (J.M. Sturtevant (1984) Proc. Natl. Acad. Sci. USA 81, 1398-1400) applied at relatively low drug concentrations where single peak transitions were produced, adequately described the differential scanning calorimetric results. At high drug concentrations, however, the presence of multipeak transitions were indicative of non-ideality.

Thermal and morphological studies of the segmented multiblock copolyesters containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and dimethyl-1,4-cyclohexane dicarboxylate were carried out using differential scanning calorimetry, small angle X-ray scattering, wide angle X-ray diffraction and dynamic mechanical analysis. Molecular origins of the thermal transitions appearing in copolyesters were assigned by the copolyester analysis at different temperatures. The hard segments in copolyesters underwent short-range and long-range ordering (crystallization) during cooling or annealing above glass transition temperature, as concluded from thermal and wide angle X-ray diffraction analysis. Annealing process affected the ordering in hard segments and annealing temperatures of 160 °C and above led to increased microphase mixing. The small angle X-ray scattering studies confirmed the microphase separated morphology of copolyesters and supported the argument of increased microphase mixing in copolyesters annealed at higher temperatures. The amount of sulfonate containing co-monomer and its presence in either hard or soft microphase affected the morphology of the copolyesters. Introduction of the sulfonate groups led to increased microphase mixing in copolyesters as well as destruction of long-range order in the hard segments. / Master of Science

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