Determinação de pressão de sublimação de cloridratos de amina através da técnica termogravimétrica

A presença de sais no petróleo ocasiona grandes problemas operacionais relacionados à corrosão, uma vez que estes acabam formando ácido clorídrico no processo de separação do óleo bruto. Com o intuito de amenizar os efeitos de corrosão ácida, aminas podem ser adicionadas no topo das colunas para agir como neutralizantes. Porém, dependendo das condições operacionais e da quantidade de amina adicionada, pode ocorrer a deposição de cloridratos de aminas, promovendo a corrosão sob depósito. Assim, o conhecimento da pressão de sublimação desses sólidos é de extrema importância para especificar as condições de operação e o melhor desempenho destes aditivos no processo. Dentro desse contexto, o objetivo deste trabalho é determinar as pressões e entalpias de sublimação de cloridratos de aminas com a técnica termogravimétrica. Devido às dificuldades encontradas para obtenção de dados precisos de pressão em baixas temperaturas, uma extensão ao método termogravimétrico foi proposta, tornando possível medir pressões na ordem de 1 0,5 Pa. As substâncias estudadas foram: brometo de amônio, cloreto de amônio, cloridrato de etanolamina, cloridrato de metilamina, cloridrato de piridina, cloridrato de trimetilamina e dicloridrato de n-(1- naftil)etilenodiamina. Resultados de pressão e entalpia de sublimação alcançados com ácido benzoico, brometo de amônio e cloreto de amônio foram validados com dados da literatura Para os demais sólidos estudados, não há muitos dados disponíveis na literatura. No entanto, como a reação de sublimação do cloreto de amônio é análoga à dos demais cloridratos de amina, as entalpias de sublimação puderam ser comparadas e os resultados encontrados foram satisfatórios. Por fim, para uma melhor aplicabilidade dos resultados obtidos, uma equação de Clausius-Clapeyron modificada foi utilizada para correlacionar os dados medidos. Uma ótima correlação foi possível para todos os sais estudados, com coeficiente de correlação sempre superior a 0,97.The presence of salts in petroleum causes operational problems related to corrosion, due to the fact that they end up forming hydrochloric acid in the crude oil separation process. In order to mitigate the effects of acid corrosion, amines can be added at the top of the columns to act as neutralizers. However, depending on the operational conditions and the amount of amine added, a deposition of amine hydrochlorides may occur, promoting under-deposit corrosion. Thus, the knowledge of the sublimation pressure of these salts has an extreme importance in trying to predict and to optimize the performance of the additives in the process. Within this context, the purpose of this study is to determine pressure and enthalpy of sublimation of amine hydrochlorides with the thermogravimetric technique. Due to the difficulties encountered to obtain precise pressure data at low temperatures, an extension of the thermogravimetric method was proposed, enabling to measure sublimation pressures in the order of 1 0,5 Pa. The substances studied were: ammonium bromide, ammonium chloride, ethanolamine hydrochloride, methylamine hydrochloride, pyridine hydrochloride, trimethylamine hydrochloride and n-(1-naphthyl)ethylenediamine dihydrochloride. Results of pressure and enthalpy of sublimation obtained with benzoic acid, ammonium bromide and ammonium chloride were validated using literature data. For other solids investigated in this study, experimental data is scarce in the literature. However, as the sublimation reaction of ammonium chloride is analogous to the others amine hydrochlorides, enthalpies of sublimation could be compared with the results found. Since similar values were observed, the results were considered satisfactory. Finally, the measured data were correlated using a modified Clausius-Clapeyron equation. A good correlation was possible for all salts studied, with correlation coefficient always higher than 0.97

Estudo da interação de líquidos iônicos com solventes orgânicos e água

Ao longo da última década, pesquisas com líquidos iônicos (LIs) apresentaram um aumento significativo, em razão das características desejáveis em diversos processos e pela facilidade em moldar suas propriedades físico-químicas. Diante disso, este trabalho tem como objetivo estudar as interações de solventes orgânicos e a água em quatro líquidos iônicos próticos (LIPs): propanoato de butilamônio ([BA][Pr]), propanoato de dietilamônio ([DEA][Pr]), propanoato de N-metil-2-hidroxietilamônio ([m-2HEA][Pr]) e propanoato de N-etil-2-hidroxietilamônio ([e-2HEA][Pr]). Os LIPs foram caracterizados por meio da Ressonância Magnética Nuclear (RMN) de 1H e 13C para confirmação da estrutura química, e avaliados quanto a sua estabilidade térmica por meio de análises termogravimétricas (TGA). Posterior a caracterização, foram determinadas propriedades termodinâmicas de misturas binárias. O equilíbrio líquido-vapor (ELV) entre água–LI foi medido por meio da técnica higrométrica, enquanto o coeficiente de atividade em diluição infinita (IDAC) de 17 solventes orgânicos em LIPs (γi;LIP 8 ), foi determinado utilizando a técnica de cromatografia gasosa inversa (IGC). Por fim, os parâmetros do modelo NRTL foram estimados utilizando os dados de ELV levantados, e a capacidade preditiva do modelo COSMO-SAC foi verificada, comparando a sua qualidade de resposta com os dados experimentais. Baseado no comportamento dos LIs frente à água, observou-se que todos os sistemas água–LIPs investigados apresentaram desvios negativos a idealidade (γi8 < 1), demonstrando alta compatibilidade entre as substâncias. Em relação as análises cromatográficas, todos os solventes orgânicos foram retidos predominantemente pela interação entre a fase líquida e vapor, com exceção dos alcanos que apresentaram alta influência da adsorção interfacial. Álcoois e organoclorados foram os solventes com maior afinidade com os LIPs estudados, com valores de IDAC próximos a unidade. Altos valores de IDAC foram encontrados para hidrocarbonetos, e o aumento da cadeia carbônica tem relação direta com o valor do IDAC. Por fim, com base no comportamento dos LIPs frente aos solventes orgânicos e à água, identificou-se uma potencial aplicação destes em processos de separação, como na obtenção de álcool anidro e na desidratação de gás natural e também na separação de hidrocarbonetos com características semelhantes, devido os altos valores de seletividade.Over the last decade, research on ionic liquids (ILs) has shown a significant increase, since they present desirable characteristics for a variety of processes and can be easily molded to give the necessary physicochemical properties. This work aims to study the interactions of organic solvents and water with four protic ionic liquids (PILs): butylammonium propionate ([BA][Pr]), diethylammonium propionate ([DEA][Pr]), N-methyl-2-hydroxiethylammonium propionate ([m-2HEA][Pr]) and Nethyl-2-hydroxiethylammonium propionate ([e-2HEA][Pr]). First, the PILs were characterized by Nuclear Magnetic Resonance (NMR) of 1H and 13C, to confirm the chemical structure, and then evaluated for their thermal stability by thermogravimetric analysis (TGA). After characterization, thermodynamic properties such as vaporliquid equilibrium (VLE), were determined for water and ILs by the hygrometric technique, and infinite dilution activity coefficient (IDAC) of 17 solvents in PIL (γi;LIP 8 ) was obtained by inverse gas chromatography (IGC) technique. Finally, the NRTL model parameters were estimated using VLE data and the predictive capacity of COSMOSAC model was assessed by comparing its response with experimental data. Based on the behavior of the ILs with water, it was observed that all water–PILs systems investigated show negative deviations to ideality (γi8 < 1), indicating a favorable interaction between water and the studied ammonium-based ILs. Regargind the chromatographic analysis, all organic solvents were mainly retained due to vapor-liquid interactions, except the n-alkanes that showed high influence of interfacial adsorption with column support. Organochlorine and alcohols were found to have strong affinity with PILs, since the IDAC values were close to unity. In general, high IDAC values were found for hydrocarbons, and the increase in the carbon chain showed a direct relation to the IDAC value. Finally, considering the behavior of LIPs in relation to organic solvents and water, potential applications of the ionic liquids in separation processes were identified. For example, in obtaining anhydrous alcohol and dehydration of natural gas, due to the strong interactions between water–LIPs, and in the separation of hydrocarbons with similar characteristics, due to the high selectivity values observed

Determinação de pressão de sublimação de cloridratos de amina através da técnica termogravimétrica

A presença de sais no petróleo ocasiona grandes problemas operacionais relacionados à corrosão, uma vez que estes acabam formando ácido clorídrico no processo de separação do óleo bruto. Com o intuito de amenizar os efeitos de corrosão ácida, aminas podem ser adicionadas no topo das colunas para agir como neutralizantes. Porém, dependendo das condições operacionais e da quantidade de amina adicionada, pode ocorrer a deposição de cloridratos de aminas, promovendo a corrosão sob depósito. Assim, o conhecimento da pressão de sublimação desses sólidos é de extrema importância para especificar as condições de operação e o melhor desempenho destes aditivos no processo. Dentro desse contexto, o objetivo deste trabalho é determinar as pressões e entalpias de sublimação de cloridratos de aminas com a técnica termogravimétrica. Devido às dificuldades encontradas para obtenção de dados precisos de pressão em baixas temperaturas, uma extensão ao método termogravimétrico foi proposta, tornando possível medir pressões na ordem de 1 0,5 Pa. As substâncias estudadas foram: brometo de amônio, cloreto de amônio, cloridrato de etanolamina, cloridrato de metilamina, cloridrato de piridina, cloridrato de trimetilamina e dicloridrato de n-(1- naftil)etilenodiamina. Resultados de pressão e entalpia de sublimação alcançados com ácido benzoico, brometo de amônio e cloreto de amônio foram validados com dados da literatura Para os demais sólidos estudados, não há muitos dados disponíveis na literatura. No entanto, como a reação de sublimação do cloreto de amônio é análoga à dos demais cloridratos de amina, as entalpias de sublimação puderam ser comparadas e os resultados encontrados foram satisfatórios. Por fim, para uma melhor aplicabilidade dos resultados obtidos, uma equação de Clausius-Clapeyron modificada foi utilizada para correlacionar os dados medidos. Uma ótima correlação foi possível para todos os sais estudados, com coeficiente de correlação sempre superior a 0,97.The presence of salts in petroleum causes operational problems related to corrosion, due to the fact that they end up forming hydrochloric acid in the crude oil separation process. In order to mitigate the effects of acid corrosion, amines can be added at the top of the columns to act as neutralizers. However, depending on the operational conditions and the amount of amine added, a deposition of amine hydrochlorides may occur, promoting under-deposit corrosion. Thus, the knowledge of the sublimation pressure of these salts has an extreme importance in trying to predict and to optimize the performance of the additives in the process. Within this context, the purpose of this study is to determine pressure and enthalpy of sublimation of amine hydrochlorides with the thermogravimetric technique. Due to the difficulties encountered to obtain precise pressure data at low temperatures, an extension of the thermogravimetric method was proposed, enabling to measure sublimation pressures in the order of 1 0,5 Pa. The substances studied were: ammonium bromide, ammonium chloride, ethanolamine hydrochloride, methylamine hydrochloride, pyridine hydrochloride, trimethylamine hydrochloride and n-(1-naphthyl)ethylenediamine dihydrochloride. Results of pressure and enthalpy of sublimation obtained with benzoic acid, ammonium bromide and ammonium chloride were validated using literature data. For other solids investigated in this study, experimental data is scarce in the literature. However, as the sublimation reaction of ammonium chloride is analogous to the others amine hydrochlorides, enthalpies of sublimation could be compared with the results found. Since similar values were observed, the results were considered satisfactory. Finally, the measured data were correlated using a modified Clausius-Clapeyron equation. A good correlation was possible for all salts studied, with correlation coefficient always higher than 0.97

Check all that apply (CATA) as an instrument for the development of fish products

Abstract The objective of this paper is to develop a fish-based product. Through the innovative sensorial check all that apply (CATA) technique, employed in two stages of the development of the product &#8211; market research and the sensorial and hedonistic characterization of the final product &#8211; the aim was to develop a fish by-product that could respond to the needs of the consumer market. Results showed that the CATA technique is an important instrument for researching the consumer market and indicated the kind of fish by-product to be developed and its desired features. Nugget was the resulting by-product. The second application of CATA made possible the sensorial description of the by-product as being crisp, with little fish odor, light in color, well-seasoned and tasty. Therefore, the CATA technique proved to be an important research instrument in the fish consumption market as well as a quick technique for the complete description of fish nuggets

Projective mapping with food stickers: A good tool for better understanding perception of fish in children of different ages

The objective of this study was to better understand the perception of fish products among school children of three different age groups, 5–6 years, 7–8 years and 9–0 years. In order to do so, we used Projective Mapping (PM) with food stickers and a word association task (WA). A total of 149 children from three public schools in the state of Parana, Brazil, have participated on this study. The age groups were interviewed (on 1–1 basis) by six monitors qualified to apply the sensory methods used. Ten stickers with drawings of healthy foods (sushi, salad, fruit, fish, chicken), and less-healthy foods (pizza, flan, cake, hamburger, french fries) were given to the children. They were then asked to stick them on an A3 sheet, in a way that the products they considered similar should be positioned close to each other, and those they considered very different should be kept apart. Afterwards, they were asked to described the images and group of images (ultra flash profile). The PM was easily used and understood by all children, and the use of images may potentially have eased its application. Result analyses showed different perceptions from the different age groups. Hedonic perceptions in relation to fish products had a higher weight in the perceptual spaces of older children. WA technique proved to be an important tool to understand fish perception by children, and reinforced the results previously obtained by PM. These results may imply that there could be a window of opportunity in which younger children will be more open to eat fish.The authors thank Capes for having provided the scholarship to Barbara Arruda Nogueira, to National Counsel of Technological and Scientific Development (CNPq) – Brazil for financing Project No. 456102/2014-0. The authors also thank Robson Piccoli for designing the food stickers. Author Paula Varela thanks the Barn&Smak project (“Children and food preferences in the light of the Norwegian taste” – KNP Project no. 233831/E50, funded by the Research Council of Norway)

Acceptance of fish hamburgers in school meals in the Southwest Region of Paraná, Brazil

<div><p>Abstract The regular consumption of fish provides health gains for people, and its introduction in school meals is an important strategy to insert the habit of consuming this food by a population. Thus the objective of this study was to verify the acceptance of fish, presented in the form of hamburger, by children in municipal primary schools in the town of Pato Branco, Brazil, in which the school cooks had been trained to produce fish hamburgers. Acceptance was evaluated using a hedonic scale with 5 facial classifications (1 = disliked extremely to 5 = liked extremely). Students of both genders from 5 to 10 years of age (n = 142) were served the hamburgers for their midday meal, representing the protein portion of the meal. The results were analyzed by logistic regression. No effect of age or gender was observed between the children in the acceptance of the hamburgers, but the interaction between age and gender was significant. The cluster analysis was applied to distinguish this interaction using two-way joining to present the results, which showed the effect between specific age and gender situations. The acceptance index was 87% showing the potential for the consumption of this food by children.</p></div