Aplicação de termogravimetria acoplada à espectrometria de massas para caracterização de petróleo e determinação da curva de evolução de gás sulfídrico

With the new discoveries of oil and gas, the exploration of fields in various geological basins, imports of other oils and the development of alternative fuels, more and more research labs have evaluated and characterized new types of petroleum and derivatives. Therefore the investment in new techniques and equipment in the samples analysis to determine their physical and chemical properties, their composition, possible contaminants, especification of products, among others, have multiplied in last years, so development of techniques for rapid and efficient characterization is extremely important for a better economic recovery of oil. Based on this context, this work has two main objectives. The first one is to characterize the oil by thermogravimetry coupled with mass spectrometry (TG-MS), and correlate these results with from other types of characterizations data previously informed. The second is to use the technique to develop a methodology to obtain the curve of evaluation of hydrogen sulfide gas in oil. Thus, four samples were analyzed by TG-MS, and X-ray fluorescence spectrometry (XRF). TG results can be used to indicate the nature of oil, its tendency in coke formation, temperatures of distillation and cracking, and other features. It was observed in MS evaluations the behavior of oil main compounds with temperature, the points where the volatilized certain fractions and the evaluation gas analysis of sulfide hydrogen that is compared with the evaluation curve obtained by Petrobras with another methodology

Avaliação do petróleo por termogravimetria para simulação de curva PEV, fator de caracterização e resíduo de carbono

Petroleum evaluation is analyze it using different methodologies, following international standards to know their chemical and physicochemical properties, contaminant levels, composition and especially their ability to generate derivatives. Many of these analyzes consuming a lot of time, large amount of samples , supplies and need an organized transportation logistics, schedule and professionals involved. Looking for alternatives that optimize the evaluation and enable the use of new technologies, seven samples of different centrifuged Brazilian oils previously characterized by Petrobras were analyzed by thermogravimetry in 25-900° C range using heating rates of 05, 10 and 20ºC per minute. With experimental data obtained, characterizations correlations were performed and provided: generation of true boiling point curves (TBP) simulated; comparing fractions generated with appropriate cut standard in temperature ranges; an approach to obtain Watson characterization factor; and compare micro carbon residue formed. The results showed a good chance of reproducing simulated TBP curve from thermogravimetry taking into account the composition, density and other oil properties. Proposed correlations for experimental characterization factor and carbon residue followed Petrobras characterizations, showing that thermogravimetry can be used as a tool on oil evaluation, because your quick analysis, accuracy, and requires a minimum number of samples and consumables

Estudo de compatibilidade e estabilidade térmica do ácido retinóico e hidroquinona por termogravimetria

Retinoic acid (RA) and hydroquinone (HQ) assets are widely used in pharmaceutical and cosmetic formulations, for having depigmenting properties and are largely produced in drugstores. To assist in the development of formulations containing the active RA and HQ National Forms of Brazilian Pharmacopoeia (2005 and 2012 ) proposes formulations with different excipients such as cetyl alcohol (AC), cetostearyl alcohol (ACT), methylparaben (MTP), propyl paraben ( PPB), glycerin (GLY), dipropylene glycol (DPG), imidazolidinil urea ( IMD ), cyclomethicone (CCM ), butylated hydroxytoluene (BHT), octyl stearate (ETO), EDTA, decil oleate (ODC) and hydroxipropymethyl celullose (HPMC). One of the difficulties found in most cosmetic formulations is the large number of incompatibilities between the components of the formulations, so the aim this study was to evaluate thermal stability and interactions between these active pharmaceutical ingredients and excipients. The depigmenting agents were analyzed by DSC and TG and excipients were analyzed by TG. The dynamic thermogravimetric curves were obtained on a SHIMADZU thermobalance, model DTG-60, using an alumina crucible, at the heating rate of 10ºC min-1, in the temperature range of 25-900 ºC, under an atmosphere of nitrogen at 50 mL min-1. The DSC curves were obtained using Shimadzu calorimeter, model DSC-60, using aluminum crucible, at the heating rate of 10ºC min-1, in the temperature range of 25-400ºC. The thermogravimetric and calorimetric curves were analyzed using TASYS software SHIMADZU. In this study no were found interactions between AR and the following excipients: MTP, PPB, IMD, ODC, EDTA, CCM, ETO, HPMC. However, were found interactions with the following excipients: AC, ACT, BHT, GLI and DPG. For HQ were found interactions with IMD and DPG. Interactions remained even changing proportions of the mixtures and the ternary. Thus, the studies conducted with excipients of National Formulary from 2005 and 2012 showed that these new excipients do not interact by thermogravimetry with the active pharmaceutical ingredients of this study

Determinação do teor de cálcio através da termogravimetria, em medicamentos utilizados no tratamento da osteoporose: um estudo comparativo

The present study utilized the thermogravimetry (TG) and optical emission spectroscopy with inductively coupled plasma - ICP / OES to determine the calcium content in tablets of carbonate, citrate and calcium lactate used in the treatment of osteoporosis. The samples were characterized by IR, SEM, TG / DTG, DTA, DSC and XRD. The thermal analysis evaluated the thermal stability and physical-chemical events and showed that the excipients influence the decomposition of active ingredients. The results of thermogravimetry indicated that the decomposition temperature of the active CaCO3 (T = 630.2 °C) is lower compared to that obtained in samples of the tablets (633.4 to 655.2 °C) except for sample AM 2 (Ti = 613.8 oC). In 500.0 °C in the samples of citrate and calcium lactate, as well as their respective active principles had already been formed calcium carbonate. The use of N2 atmosphere resulted in shifting the initial and final temperature related to the decomposition of CaCO3. In the DTA and DSC curves were observed endo and exothermic events for the samples of tablets and active ingredients studied. The infrared spectra identified the main functional groups in all samples of active ingredients, excipients and tablets studied, such as symmetric and asymmetric stretches of the groups OH, CH, C = O. Analysis by X-ray diffraction showed that all samples are crystalline and that the final residue showed peaks indicative of the presence of calcium hydroxide by the reaction of calcium oxide with moisture of the air. Although the samples AM 1, AM 2, AM 3 and AM 6 in their formulations have TiO2 and SiO2 peaks were not observed in X-ray diffractograms of these compounds. The results obtained by TGA to determine the calcium content of the drugs studied were satisfactory when compared with those obtained by ICP-OES. In the AM 1 tablet was obtained the content of 35.37% and 32.62% for TG by ICP-OES, at 6 AM a percentage of 17.77% and 16.82% and for AM 7 results obtained were 8.93% for both techniques, showing that the thermogravimetry can be used to determine the percentage of calcium in tablets. The technique offers speed, economy in the use of samples and procedures eliminating the use of acid reagents in the process of the sample and efficiency results.

Aplicação da termogravimetria na determinação do teor de ferro em comprimidos: um estudo comparativo com a espectrofotometria

This study used the Thermogravimetry (TG) and molecular absorption spectroscopy in UV-visible region to determine the iron content in herbal medicinal ferrous sulfate used in the treatment of iron deficiency anemia. The samples were characterized by IR, UV, TG / DTG, DTA, DSC and XRD. The thermoanalytical techniques evaluated the thermal stability and physicochemical events and showed that the excipients interfere in the decomposition of the active ingredients. The results of thermogravimetry showed that the decomposition temperature of the active principle Fe2(SO4)3 (T = 602 °C) is higher as compared to samples of tablets (566 586 °C). In the DTA and DSC curves were observed exothermic and endo events for samples of medicines and active analysis. The infrared spectra identified key functional groups exist in all samples of active ingredients, excipients and compressed studied, such as symmetric and asymmetric stretching of OH, CH, S=O. The analysis by X-ray diffraction showed that all samples had crystallinity and the final residue showed peaks indicating the presence of silicon dioxide, titanium dioxide and talc that are excipients contained in pharmaceutical formulations in addition to iron oxide. The results obtained by TG to determine the iron content of the studied drugs showed a variance when compared with those obtained by theoretical and UV-visible, probably due to formation of a mixture of Fe2O3 and Fe2(SO4)3. In one tablet was obtained FE content of 15.7 % and 20.6 % for TG by UV-visible, the sample EF 2 was obtained as a percentage of 15.4 % and 21.0 % for TG by UV-visible . In the third SF samples were obtained a content of 16.1 % and 25.5 % in TG by UV-visible, and SF 4 in the percentage of TG was 16.7 % and 14.3 % UV-visible

Ilustração da influência da razão de aquecimento nos resultados de termogravimetria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aplicação da destilação simulada por cromatografia gasosa e da termogravimetria para a avaliação da influência da redução do teor de enxofre sobre as propriedades físico-químicas do óleo diesel

One of the main problems related to the use of diesel as fuel is the presence of sulfur (S) which causes environmental pollution and corrosion of engines. In order to minimize the consequences of the release of this pollutant, Brazilian law established maximum sulfur content that diesel fuel may have. To meet these requirements, diesel with a maximum sulfur concentration equal to 10 mg/kg (S10) has been widely marketed in the country. However, the reduction of sulfur can lead to changes in the physicochemical properties of the fuel, which are essential for the performance of road vehicles. This work aims to identify the main changes in the physicochemical properties of diesel fuel and how they are related to reduction of sulfur content. Samples of diesel types S10, S500 and S1800 were tested according with the methods of the American Society for Testing and Materials (ASTM). The fuels were also characterized by thermogravimetric analysis (TG) and subjected to physical distillation (ASTM D86) and simulated distillation gas chromatography (ASTM D2887). The results showed that the reduction of sulfur turned the fuel lighter and fluid, allowing a greater applicability to low temperature environments and safer for transportation and storage. Through the simulated distillation data was observed that decreasing sulfur content resulted in higher initial boiling point temperatures and the decreasing of the boiling temperature of the medium and heavy fractions. Thermogravimetric analysis showed a loss event mass attributed to volatilization or distillation of light and medium hydrocarbons. Based on these data, the kinetic behavior of the samples was investigated and it was observed that the activation energies (Ea) did not show significant changes throughout conversion. Considering the average of these energies, the S1800 had the highest Ea during the conversion and the S10 the lowest values

Aplicação de termogravimetria acoplada à espectrometria de massas para caracterização de petróleo e determinação da curva de evolução de gás sulfídrico

With the new discoveries of oil and gas, the exploration of fields in various geological basins, imports of other oils and the development of alternative fuels, more and more research labs have evaluated and characterized new types of petroleum and derivatives. Therefore the investment in new techniques and equipment in the samples analysis to determine their physical and chemical properties, their composition, possible contaminants, especification of products, among others, have multiplied in last years, so development of techniques for rapid and efficient characterization is extremely important for a better economic recovery of oil. Based on this context, this work has two main objectives. The first one is to characterize the oil by thermogravimetry coupled with mass spectrometry (TG-MS), and correlate these results with from other types of characterizations data previously informed. The second is to use the technique to develop a methodology to obtain the curve of evaluation of hydrogen sulfide gas in oil. Thus, four samples were analyzed by TG-MS, and X-ray fluorescence spectrometry (XRF). TG results can be used to indicate the nature of oil, its tendency in coke formation, temperatures of distillation and cracking, and other features. It was observed in MS evaluations the behavior of oil main compounds with temperature, the points where the volatilized certain fractions and the evaluation gas analysis of sulfide hydrogen that is compared with the evaluation curve obtained by Petrobras with another methodology

Avaliação do petróleo por termogravimetria para simulação de curva PEV, fator de caracterização e resíduo de carbono

Petroleum evaluation is analyze it using different methodologies, following international standards to know their chemical and physicochemical properties, contaminant levels, composition and especially their ability to generate derivatives. Many of these analyzes consuming a lot of time, large amount of samples , supplies and need an organized transportation logistics, schedule and professionals involved. Looking for alternatives that optimize the evaluation and enable the use of new technologies, seven samples of different centrifuged Brazilian oils previously characterized by Petrobras were analyzed by thermogravimetry in 25-900° C range using heating rates of 05, 10 and 20ºC per minute. With experimental data obtained, characterizations correlations were performed and provided: generation of true boiling point curves (TBP) simulated; comparing fractions generated with appropriate cut standard in temperature ranges; an approach to obtain Watson characterization factor; and compare micro carbon residue formed. The results showed a good chance of reproducing simulated TBP curve from thermogravimetry taking into account the composition, density and other oil properties. Proposed correlations for experimental characterization factor and carbon residue followed Petrobras characterizations, showing that thermogravimetry can be used as a tool on oil evaluation, because your quick analysis, accuracy, and requires a minimum number of samples and consumables

Characterization and evaluation of melibiose as novel excipient in tablet compaction

Lactose is probably the most used tablet excipient in the field of pharmacy. Although lactose is thoroughly characterized and available in many different forms there is a need to find a replacer for lactose as a filler/binder in tablet formulations because it has some downsides. Melibiose is a relatively unknown disaccharide that has not been thoroughly characterized and not previously used as an excipient in tablets. Structurally melibiose is close to lactose as it is also formed from the same two monosaccharides, glucose and galactose. Aim of this research is to characterize and to study physicochemical properties of melibiose. Also the potential of melibiose to be used as pharmaceutical tablet excipient, even as a substitute for lactose is evaluated. Current knowledge about fundamentals of tableting and methods for determinating of deformation behavior and tabletability are reviewed. In this research Raman spectroscopy, X-ray powder diffraction (XRPD), near-infrared spectroscopy (NIR) and Fourier-transform infrared spectroscopy (FT-IR) were used to study differences between two melibiose batches purchased from two suppliers. In NIR and FT-IR measurements no difference between materials could be observed. XPRD and Raman however found differences between the two melibiose batches. Also the effects of moisture content and heating to material properties were studied and moisture content of materials seems to cause some differences. Thermal analytical methods, differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to study thermal behaviour of melibiose and difference between materials was found. Other melibiose batch contains residual water which evaporates at higher temperatures causing the differences in thermal behaviour. Scanning electron microscopy images were used to evaluate particle size, particle shape and morphology. Bulk, tapped and true densities and flow properties of melibiose was measured. Particle size of the melibiose batches are quite different resulting causing differences in the flowability. Instrumented tableting machine and compression simulator were used to evaluate tableting properties of melbiose compared to α-lactose monohydrate. Heckel analysis and strain-rate sensitivity index were used to determine deformation mechanism of melibiose monohydrate in relation to α–lactose monohydrate during compaction. Melibiose seems to have similar deformation behaviour than α-lactose monohydrate. Melibiose is most likely fragmenting material. Melibiose has better compactibility than α – lactose monohydrate as it produces tablets with higher tensile strength with similar compression pressures. More compression studies are however needed to confirm these results because limitations of this study.

Avaliação das propriedades de barreira a gases de membranas obtidas a partir de dispersões aquosas à base de poliuretanos e argila

Materiais nanoestruturados têm recebido destaque na comunidade científica, destacando-se, dentre eles, os nanocompósitos à base de polímeros e argila. Quando esses materiais são obtidos no estado líquido, ressalta-se também o uso de água em substituição a solventes orgânicos, devido a questões ambientais. Neste trabalho foram sintetizadas dispersões aquosas à base de poliuretanos (WPUs) e argila hidrofílica do tipo montimorilonita (MMT) de natureza sódica, com o objetivo de avaliar as propriedades de barreira a gases conferidas pela presença de argila e pela variação nas proporções entre os segmentos flexíveis poli(glicol propilênico) (PPG) e o copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG). Os monômeros empregados na síntese foram: poli(glicol propilênico) (PPG); copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 7% de EG; ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e etilenodiamina (EDA), como extensor de cadeia. Foram sintetizadas dispersões aquosas com e sem a presença de argila, fixando-se a razão entre o número de equivalentes-grama de grupos diisocianato e hidroxila (razão NCO/OH) em 1,5. Nas formulações foi variado também o teor de argila em relação à massa de prepolímero em 0,5% e 1%. Foi adicionada uma etapa de agitação adicional com dispersor Turrax em algumas formulações. A argila foi previamente deslaminada em água deionizada e incorporada à formulação na etapa da dispersão do prepolímero. As dispersões foram avaliadas, quanto ao teor de sólidos totais, tamanho médio de partícula e viscosidade aparente. Os filmes vazados a partir das dispersões foram caracterizados por espectrometria na região do infravermelho (FTIR) e permeabilidade ao CO2. A resistência térmica dos filmes foi determinada por termogravimetria (TG). Foram observadas modificações nas propriedades dos filmes obtidos com a inserção da argila e com a variação no teor de segmentos à base de poli(glicol etilênico). A inserção da argila promoveu uma melhoria na resistência térmica das membranas bem como uma redução na permeabilidade das mesmas. Foi observado um aumento na permeabilidade das membranas obtidas a partir das formulações com maior percentual de copolímero (EG-b-PG), com e sem argila.

Estudo da influência do teor de segmentos hidrofílicos na síntese de poliuretanos dispersos em água

Considerações ambientais têm aumentado a pesquisa e o desenvolvimento de sistemas poliméricos aquosos para diversos tipos de aplicações, principalmente como revestimentos. Nesta dissertação, foram sintetizadas formulações não-poluentes à base de poliuretanos dispersos em água (PUDs), com 40% de teor de sólidos, na ausência de solventes orgânicos. Os monômeros empregados foram copolímeros em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 25% de segmento hidrofílico EG, poli (glicol propilênico) (PPG), ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e hidrazina (HYD), como extensor de cadeia. Foram variadas as razões entre o número de equivalente-grama de grupamentos isocianato e hidroxila (NCO/OH) e a proporção em equivalente-grama de PPG e dos copolímeros em bloco (EG-b-PG). Foi observado que a incorporação de altas quantidades de copolímero dificultou a síntese dos poliuretanos dispersos em água, levando à formação de géis. O tamanho médio de partícula e a viscosidade das dispersões foram determinados. Os filmes vazados a partir dessas dispersões foram avaliados quanto à capacidade de absorção de água, resistência mecânica, termogravimetria (TG), e caracterizados por espectroscopia na região do infravermelho (FTIR). As dispersões poliuretânicas produzidas se mostraram satisfatórias quando aplicadas como revestimento para madeira, metais e vidro

Copolimerização de 1,3-butadieno e alfa-olefinas com catalisadores à base de versatato de neodímio

Nesta Dissertação, foram realizadas reações de copolimerização de 1,3-butadieno com diferentes alfa-olefinas (1-hexeno, 1-octeno e 1-dodeceno) utilizando-se um sistema catalítico do tipo Ziegler-Natta ternário constituído por versatato de neodímio, hidreto de diisobutilalumínio e cloreto de t-butila. O sistema catalítico também foi avaliado em reações de homopolimerização com cada alfa-olefina. As condições reacionais, tanto da síntese do catalisador como das reações de polimerização, foram mantidas constantes. Foi estudada a influência de diferentes teores de cada alfa-olefina (1, 3, 5, 10, 20 e 30 % em relação ao 1,3-butadieno) sobre a conversão da polimerização, a microestrutura, a massa molar, as propriedades viscosimétricas e a estabilidade térmica dos polímeros obtidos. Foi avaliada, ainda, a influência do tamanho da cadeia da alfa-olefina sobre as características da polimerização. Os polímeros foram caracterizados por espectroscopia na região do infravermelho (FTIR), cromatografia por exclusão de tamanho (SEC), viscosimetria capilar e termogravimetria (TG). A microestrutura dos polímeros, praticamente, não variou com a adição das alfa-olefinas. A massa molar numérica média (Mn) não sofreu alterações significativas, enquanto que a massa molar ponderal média (Mw) apresentou tendência ao aumento, quanto maior foi a incorporação de comonômero. A viscosidade intrínseca não apresentou uma tendência com a adição da alfa-olefina na reação, permanecendo na faixa de 2,015 a 3,557 dL/g. A estabilidade térmica do copolímero mostrou uma tendência a aumentar com a incorporação das alfa-olefinas

Avaliação de propriedades de artefatos à base de borracha natural

A combinação de excelentes propriedades mecânicas aliadas à biocompatibilidade torna a borracha natural um material amplamente empregado na fabricação de artefatos voltados à saúde, tais como bicos de chupetas e de mamadeiras, e luvas cirúrgicas e de procedimentos não-cirúrgicos. Esses artefatos são processados a partir de látices de poli(cis-isopreno) extraído de seringueiras. Entretanto, o grande número de insaturações presentes na cadeia polimérica, mesmo após a vulcanização, resulta em uma baixa resistência desse material ao envelhecimento, causado principalmente pela associação de fatores como temperatura, oxigênio, ozônio e radiação. Outro inconveniente associado à aplicação da borracha natural é a presença de proteínas no látex, com potencial alergênico, podendo promover reações fisiológicas em alguns usuários. Por esse motivo artefatos comerciais à base de material sintético também são encontrados no mercado. Esses artefatos também não são isentos dos processos naturais de desgaste e decomposição. Esta Dissertação teve como objetivo realizar um estudo comparativo de propriedades dos produtos comerciais à base de borracha natural e à base de material sintético (bicos de chupeta e de mamadeiras e luvas) de diferentes fabricantes, como adquiridos e após sofrerem envelhecimento acelerado. O estudo foi feito empregando-se as técnicas de espectroscopia na região do infravermelho com transformada de Fourier (FTIR) e termogravimetria (TG). Uma avaliação mecânica com métodos padronizados foi também realizada

Estudo da incorporação de diferentes tipos de argilas hidrofílicas em dispersões aquosas de poliuretanos para formação de nanocompósitos

Neste trabalho foram sintetizados nanocompósitos à base de poliuretanos em dispersão aquosa (NWPUs) e argilas hidrofílicas do tipo montimorilonita (MMT) de natureza sódica e cálcica. Os monômeros empregados na síntese foram: poli(glicol propilênico) (PPG); copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 7% de EG; ácido dimetilolpropiônico (DMPA) e diisocianato de isoforona (IPDI). Os NWPUs tiveram as argilas, previamente deslaminadas em água e incorporadas à formulação no momento da dispersão do prepolímero. Dispersões aquosas (WPUs), sem a presença de argila, foram sintetizadas como base, nas quais foram variadas a razão NCO/OH e a proporção de copolímero em relação ao PPG. Nas formulações NWPUs, foram variados também o teor de argila em relação à massa de prepolímero e o tipo de argila sódica e cálcica. As dispersões foram avaliadas, quanto ao teor de sólidos totais, tamanho médio de partícula e viscosidade. Os filmes vazados a partir das dispersões foram caracterizados por espectrometria na região do infravermelho (FTIR), difração de raios-x (XRD) e microscopia eletrônica de varredura (SEM). A resistência térmica dos filmes foi determinada por termogravimetria (TG) e a resistência mecânica dos filmes foi avaliada por ensaios mecânicos em dinamômetro. O grau de absorção de água dos filmes também foi determinado. A formação de nanocompósitos à base de água foi confirmada pela ausência do pico de XRD, característico das argilas empregadas na maioria dos filmes analisados. As micrografias obtidas por SEM confirmam uma dispersão homogênea das argilas na matriz poliuretânica. Os filmes à base de nanocompósitos (NWPUs) apresentaram propriedades superiores às apresentadas por aqueles obtidos a partir das dispersões sem argilas (WPUs). Os revestimentos formados a partir da aplicação das dispersões aderiram à maioria dos substratos testados (metal, vidro, madeira e papel) formando superfícies homogêneas