Extractive Distillation of Benzene and Cyclohexane by Using 1-propyronitrile- 3-butylimidazolium dicyanamide

Due to very close boiling point of benzene and cyclohexane (~Tb = 0.6°C), separation of them is one of the most challenging processes in the chemical industry and it is not practical to separate such a binary mixture by conventional distillation process. The separation efficiency of ionic liquid as a solvent in the extractive distillation process, COSMO-RS generated the information of potentially applicable ionic liquid of 1-propyronitrile-3-butylimidazolium dicyanamide [C2CNBim]N(CN)2 with aromatic compound and aliphatic compound is studied at temperature range (293.15 to 323.15) K and at atmospheric pressure. Firstly, the ionic liquid is synthesized and its property measurements is characterized. Then study on thermophysical properties of ionic liquid is done by preparing 1-propyronitrile-3- butylimidazolium dicyanamide added with benzene at different compositions and their density and refractive indices are measured at the stated temperature and pressure. Thermal expansion coefficients are estimated using the measured density values. Secondly, headspace-gas chromatography (HSGC) experiments are done at the stated conditions to calculate the relative volatility of the sytstem by measuring and observing vapor-liquid equilibrium (VLE) data for the ternary systems (benzene+cyclohexane) with the ionic liquid. So far there is no available thermophysical data of 1-propyronitrile-3-butylimidazolium dicyanamide with aromatic compound yet and there is no available data on relative volatility of this ionic liquid with benzene and cyclohexane. All of these reasons have given me the motivation to carry out this study

Extractive Distillation of Benzene and Cyclohexane by Using 1-propyronitrile- 3-butylimidazolium dicyanamide

Due to very close boiling point of benzene and cyclohexane (~Tb = 0.6°C), separation of them is one of the most challenging processes in the chemical industry and it is not practical to separate such a binary mixture by conventional distillation process. The separation efficiency of ionic liquid as a solvent in the extractive distillation process, COSMO-RS generated the information of potentially applicable ionic liquid of 1-propyronitrile-3-butylimidazolium dicyanamide [C2CNBim]N(CN)2 with aromatic compound and aliphatic compound is studied at temperature range (293.15 to 323.15) K and at atmospheric pressure. Firstly, the ionic liquid is synthesized and its property measurements is characterized. Then study on thermophysical properties of ionic liquid is done by preparing 1-propyronitrile-3- butylimidazolium dicyanamide added with benzene at different compositions and their density and refractive indices are measured at the stated temperature and pressure. Thermal expansion coefficients are estimated using the measured density values. Secondly, headspace-gas chromatography (HSGC) experiments are done at the stated conditions to calculate the relative volatility of the sytstem by measuring and observing vapor-liquid equilibrium (VLE) data for the ternary systems (benzene+cyclohexane) with the ionic liquid. So far there is no available thermophysical data of 1-propyronitrile-3-butylimidazolium dicyanamide with aromatic compound yet and there is no available data on relative volatility of this ionic liquid with benzene and cyclohexane. All of these reasons have given me the motivation to carry out this study

Density, refractive index, apparent volumes and excess molar volumes of four protic ionic liquids + water at T=298.15 AND 323.15 K

Densities and refractive index of binay mixtures of water with four protic ionic liquids, based on ammonium and fatty acids, were measured at 298.15 and 323.15 K, under atmospheric pressure. Apparent and excess molar volumes were obtained by experiments and fitting data to the Redlich-Meyer (RM), Redlich-Kister (RK) and Prigogine-Flory-Patterson (PFP) equations. The molar volume values were high, suggesting strong ion-solvent interaction. The same interaction also became stronger as the temperature increased. Excess volume values were negative, indicating that packing efficiency ability or attractive interactions occurred in mixtures of ionic liquid + water. The errors (AARD) for the properties in excess were in the range of 1.8% to 7.2%. The PFP error for the apparent volume was in the range of 0.34% to 0.06%, lower than the RM error for the same property, which was in the range of 0.70 to 1.55%. The Gladstone-Dale model was applied to correlate the refractive index of the binary mixture with the density from the values of both pure components323671682FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2011/19736-

Representation/prediction of physico-chemical properties of ionic liquids through different computational methods.

Ph. D. University of KwaZulu-Natal, Durban 2014.The “green” industrial chemical processes are of great interest to scientists and engineers due to elimination of environmental pollution, especially air pollution. One of the most important air pollutants is class of materials called volatile organic compounds (VOCs) which are widely used in different industrial chemical processes. The recent research has revealed that ionic liquids (ILs) are generally the best possible alternative to the conventional solvents; because in general, the ILs have interesting properties such as very low vapor pressure, nonflammability, and high physical and chemical stability. Ionic liquids are constituted of ions, typically a cation and an anion, and their thermophysical properties are strongly dependent on the type and chemical structure of the cation and anion. As a result, in theory, they can be designed for specific applications with certain properties by choosing the appropriate combination of anion/cation pair. For this purpose, a predictive model is required to estimate the target property based on the chemical structure of ions. At the initial step of this study, the NIST Standard Reference Database #103b as well as the published papers in the literature was chosen as the source of experimental data of ionic liquids. As a result, a large database was collected covering several thermophysical properties of ILs. Thereafter, the collected data were examined carefully and the duplicated and erroneous data were screened. Speed of sound, heat capacity, refractive index, viscosity, infinite dilution activity coefficient () , and critical temperature of various ionic liquids were modeled by means of two well-known property estimation methods, Group Contribution (GC) and Quantitative Structure-Property Relationship (QSPR) methods. These methods were combined with different computational and regression techniques such as genetic function approximation (GFA) and least square support vector machine (LS-SVM). The combined routines then were applied to select reasonable number of parameters from thousands of variables and to develop the predictive models for representation/prediction of chosen temperature-dependent thermophysical properties of ionic liquids. Speed of sound in ionic liquids was modeled successfully and two models were developed, one GC and one QSPR model. These models were the first GC and QSPR models developed for this property in the literature. Both models had better accuracy in terms of average absolute relative deviation (the AARD% of 0.36 for the GC and 0.92% for the QSPR models over 41 ILs) and covered a wider range of ionic liquids compared with the previous models published (AARD% of 1.96% over 14 ILs) and consequently, they were more applicable. Liquid heat capacity of ionic liquids was studied and one GC and one QSPR model were developed. Both models covered 82 ILs which was a larger number of ionic liquids compared with the best available model in the literature (32 ILs with an AARD% of 0.34%) and had relatively low AARD%. The AARD% of the models was 1.68% and 1.70% for the GC and QSPR models, respectively. In addition, the QSPR model was the first model developed for this property through the QSPR approach. For the refractive index of ionic liquids, little attention had been given to modeling and consequently, one new GC (AARD% = 0.34%) and the first QSPR (AARD% = 0.51%) models were developed to predict this property using the experimental data for 97 ionic liquids. Both models covered a wider range of ionic liquids and showed very good prediction ability compared with the best available model (an AARD% of 0.18% for 24 ILs). Viscosity of Fluorine-containing ionic liquids was studied because the insertion of fluorinated moieties in the molecular structure of ionic liquids could result in reduction of viscosity. As a result, one QSPR (AARD% = 2.91%) and two GC models were developed using two different databases, one with fewer number of ionic liquids but with more reliable data (AARD% = 3.23%), the one with larger number of ionic liquids but with lower reliability (AARD% = 4.85%). All of the models developed had better prediction ability compared with the previous models and covered a wider range of fluorinated ionic liquids. Infinite dilution activity coefficient (γ∞) of organic solutes was modeled by developing six different models for different types of solutes (alkane, alkene, aromatic, etc.). The model developed were the first GC models for the prediction of γ∞ of solutes in ionic liquids. They were much easier to use, more comprehensive, and much more accurate compared with the UNIFAC model. Ultimately, the theoretical critical temperature (Tc) of ionic liquids was tried to model using the GC and QSPR approaches. The experimental data of surface tension of 106 ionic liquids were used to calculate the critical temperature and then, these values were used to develop the models. It was found that the only available model in the literature was not accurate and predictive enough when its output was compared with the abovementioned Tc values. In addition, it was found that both of the models developed were not predictive enough to calculate the Tc of various types of ionic liquids as the models were developed using a few number of ionic liquids; however both models were accurate enough to fit the used values of Tc. The GC model has an AARD% of 5.17% and the QSPR model showed the AARD% of 4.69%. It this thesis, much larger databases were used to develop the models compared with the models published previously in the literature. It was found that thermophysical properties of ionic liquids can be modeled fairly well by combination of the GC or QSPR methods with an appropriate regression technique. In addition, the developed models improved significantly the quality of fit and predictions for a wider range of ionic liquids compared with the previous models. Consequently, the models proposed are more predictive and can be used to design the ionic liquids with desired property for specific applications.Please note that the symbol that appears after "coefficient " that appears in brackets "( )" could not be copied. Please refer to page i of the thesis abstract to look at the symbol

THERMOPHYSICAL PROPERTIES AND CARBON DIOXIDE SOLUBILITY OF NOVEL ROOM TEMPERATURE IONIC LIQUIDS

In the present work, a novel series of 1-alkyl-3-propanenitrile imidazolium-based room temperature ionic liquids (RTILs) ([C2CN Rim]+, where R = butyl, hexyl, octyl, decyl, allyl, ethoxyl, benzyl, incorporating sulfonate-based anions (dioctylsulfosuccinate (DOSS), dodecylsulfate (DDS), sulfobenzoic acid (SBA), benzenesulfonate (BS) and triflouromethanesulfonate (TFMS)) were synthesized. Trialkylphosphonium-based monocationic and dicationic RTILs incorporating dioctylsulfosuccinate anion ([Pn,n,n,14][dioctylsulfosuccinate] where n = 6, 8 and [P8,8,8 Cy P8,8,8][dioctylsulfosuccinate] where y = 6, 10) were also synthesized. The molecular structures of the thirty four RTILs synthesized were confirmed using 1H and 13C NMR, FTIR and elemental analysis. The densities and viscosities of the present RTILs were measured at atmospheric pressure at T = 293.15 to 353.15 K, refractive index was measured at T = 293.15 to 333.15 K, whereas, the start and decomposition temperatures were determined at heating rate 10 Cmin-1. The thermal expansion coefficient, densities at range of temperatures and pressures, molecular volume, molar refraction, standard entropy and lattice energy of these RTILs were also estimated. The present RTILs showed lower densities, similar refractive indices and higher viscosities compared to the other imidazolium and phosphonium-based RTILs. The thermogravimetric results exhibited short-term thermal stability in the range between 470 to 670 K. These RTILs showed a weak temperature dependency on the thermal expansion coefficients, αp = 5.0 × 10−4 to 7.50 × 10−4 K-1. Empirical correlations were proposed to represent the present data on the physical properties. The densities of the present imidazolium-based RTILs are highest when paired with TFMS anion followed by SBA, BS and DDS anion. The lowest densities was observed with DOSS anion. The measured viscosities are higher for the RTILs with DOSS anion, while it was the lowest with TFMS anion. viii The solubility of CO2 in the synthesized RTILs was measured using gravimetric measurement technique (magnetic suspension balance) at T = 298 to 343 K and pressures P = 1 to 20 bar. The results showed that CO2 solubility is influenced by the alkyl chain, functional group and nature of the cation and anion. The solubility of CO2 increases with an increase in pressure and decreases with increasing temperature. The solubility of the present RTILs is described using the Henry‘s law constant along with some thermodynamic properties such as molar enthalpy, entropy and Gibb‘s free energy. The ILs with the DOSS anion has a considerably higher affinity for CO2 compared with the ILs incorporating DDS, TFMS, SBA and BS anions. The [C2CNDim]DOSS, [C2CNHeim]DOSS and [P8,8,8,14]DOSS ILs have a higher solubility capacity among the studied imidazolium-based nitrile functionalized ILs, imidazolium-based dual functionalized ILs and phosphonium-based ILs respectively. Moreover, [C2CNDim]DOSS IL shows the highest CO2 solubility. The magnitude of ΔH0 decreases from that for moderately strong acid-base bonds at 298 K to that for weak acid-base bonds at 343 K for [C2CNHeim]DOSS and [P8,8,8,14]DOSS ILs while [C2CNDim]DOSS shows a very small decrease. [C2CNHeim]DOSS shows greater IL/CO2 interactions compare to [C2CNDim]DOSS and [P8,8,8,14]DOSS but the effect of temperature on this interaction was lower for [C2CNDim]DOSS. There was a considerable increase in CO2/CH4 solubility selectivity relative to the corresponding non functionalized imidazolium-based ILs. The highest selectivity obtained with non functionalized ILs ([APMim]BF4) is around 47 while for the nitrile functionalized IL ([C2CNDim]DOSS) is 82.7. The CO2/CH4 selectivity for the nitrile functionalized IL ([C2CNDim]DOSS was approximately four times higher than that of the [bmim]BF4,[emim]NTf2 and Sulfolane. Moreover, the recyclability studies indicated that the CO2 solubility capacity of the studied IL could be maintained for several cycles

Estudo do comportamento da co-combustão da borra de café e do bagaço de cana-de-açúcar

With the unbridled growth of energy demand, the use based on fossil fuels has become a global problem. However, the search for sources that are less harmful to the environment began to intensify, and an alternative that has been adopted is the use of renewable sources, especially biomass. The work aimed to carry out the development of studies in international databases on the biomass co-combustion process, in addition to studying the co-combustion process of coffee grounds (BCF) and sugarcane bagasse (BCC), characterizing the physicochemical properties of these residues. To carry out the work, a bibliometric study was carried out using keywords in the Web of Science databases - Main Collection and Science Direct, analyzing the studies that addressed the chosen theme, as well as analyzes of the BCF and BCC through the characterizations physicochemical analysis of samples (immediate analysis, higher calorific value analysis and X-ray fluorescence) and thermogravimetric analysis. The results obtained showed that, through the literature review of the databases, studies on the subject are growing over the years, especially from 2016 to 2020, as it was also noted that in the vast majority of studies the co-combustion process was made between biomasses with coal and that with co-combustion the value of the activation energy (Ae) was lower than the combustion of each residue. The results of the immediate analysis showed that the levels of volatile material found both for the samples (BCF and BCC) and for the fixed carbon showed that there is a large amount of compounds that can be devolatilized, in addition to the values obtained from PCS BCF (18.34 MJ.kg-1) and BCC (18.05 MJ.kg-1) are comparable to traditional biomass fuels that have already been used for energy purposes. Through thermogravimetric analysis it was noted that the beginning of the thermal decomposition of BCF and BCC occurred in the range of 150 ºC, as well as that, in the oxidizing atmosphere, there was a thermal stability of the samples at lower temperatures. And regarding the co-combustion process, it was observed that the greatest mass loss occurs around 150 ºC to 350 ºC in all mixtures, and the mixture of 25% BCF with 75% BCC was the most reactive either by the Ignition temperature (Tig) (175 °C) and by the higher rate of mass loss at a lower temperature (25%.min-1 at 402 °C). Therefore, through this work it was possible to have an overview of the production of articles and that BCF and BCC biomass and their mixtures may have a good applicability in their use for energy purposes in combustion processes.NenhumaCom o crescimento desenfreado pela demanda energética, a utilização baseada em combustíveis fósseis tornou-se uma problemática mundial. No entanto, a busca por fontes menos prejudiciais ao meio ambiente passou a se intensificar, e uma alternativa que tem sido adotada é a utilização de fontes renováveis, em especial a biomassa. O trabalho teve como objetivo realizar o desenvolvimento de estudos em bancos de dados internacionais sobre o processo de co-combustão de biomassas, além de estudar o processo de co-combustão da borra de café (BCF) e do bagaço de cana-de-açúcar (BCC), caracterizando as propriedades físico-químicas destes resíduos. Para realização do trabalho foi feito um estudo bibliométrico através de palavras-chave nos bancos de dados Web of Science - Coleção Principal e Science Direct, analisando os estudos que abordaram sobre a temática escolhida, como também análises da BCF e do BCC por meio das caracterizações físico-químicas das amostras (análise imediata, análise do poder calorífico superior e fluorescência de raios X) e análise termogravimétrica. Os resultados obtidos mostraram que através da revisão de literatura dos bancos de dados os estudos sobre a temática estão crescendo com o passar dos anos, principalmente de 2016 a 2020, como também foi notado que na grande maioria dos estudos o processo de co-combustão era feito entre biomassas com carvão e que com a co-combustão o valor da energia de ativação (Ea) era menor do que a combustão de cada resíduo. Já os resultados da análise imediata mostraram que os teores de material volátil encontrados tanto para as amostras (BCF e BCC) como os do carbono fixo apontaram que há uma grande quantidade de compostos que podem ser devolatilizados, além de que, os valores obtidos do PCS da BCF (18,34 MJ.kg-1) e do BCC (18,05 MJ.kg-1) são comparáveis aos dos combustíveis tradicionais de biomassa que já foram utilizadas para fins energéticos. Através das análises termogravimétricas notou-se que o início da decomposição térmica da BCF e do BCC ocorreu na faixa dos 150 ºC, como também, que na atmosfera oxidante teve uma estabilidade térmica das amostras em temperaturas inferiores. E com relação ao processo de co-combustão, observou-se que a maior perda de massa ocorre em torno de 150 ºC a 350 ºC em todas as misturas, e a mistura de 25% de BCF com 75% de BCC foi a mais reativa seja pela Temperatura de ignição (Tig) (175 ºC) e pela a maior taxa de perda de massa a uma menor temperatura (25%.min-1 a 402 ºC). Logo, por meio desse trabalho foi possível ter uma visão geral sobre as produções de artigos e que as biomassas BCF e BCC e as suas misturas, poderão ter uma boa aplicabilidade no seu aproveitamento para fins energéticos nos processos de combustão

Kinetic study of the pyrolysis of energy cane species Saccharum robustum Linnaeus using thermogravimetric analysis

Orientador: Katia TannousDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuímicaResumo: Este trabalho tem como objetivo estudar a cinética de decomposição da cana energia da espécie Saccharum robustum mediante o uso da técnica de termogravimetria. A biomassa utilizada foi in natura com diâmetro médio de 253,5 microns. As análises termogravimétricas foram realizadas nas taxas de aquecimento de 5, 10, 15 e 20 K/min sob a atmosfera de nitrogênio. Para a modelagem cinética foram utilizados modelos globais de Ozawa-Flynn-Wall, Vyazovkin e Friedman, obtendo energias de ativação médias de 172, 170 e 173 kJ/mol, respectivamente para a faixa de conversão entre 0,18 e 0,95. O método das Master Plots aplicado juntamente aos modelos globais não identificou uma única função de conversão capaz de representar a decomposição térmica experimental. Modelos multicomponentes foram mais adequados à representação da decomposição da biomassa, sendo divididos em quatro reações, representadas pelos componentes extrativos, hemicelulose, celulose e lignina. Esquemas de reações paralelas e independentes (ERPI) com ordem n, modelo de energia de ativação distribuída e modelo de deconvolução usando funções de Fraser-Suzuki foram avaliados. O modelo de reações de ordem n apresentou boa adequação com energias de ativação de 105, 153, 181 e 58 kJ/mol, ordens de reação de 1,1, 1,3, 1,0 e 3,0; fator pré-exponencial de 5×108, 7,6×1011, 5,8×1012 e 64,7 1/s e composição de 0,13, 0,2, 0,43 e 0,24, respectivamente, a cada componente considerado. Modelo de energia distribuída apresentou valores bem próximos ao ERPI, com composições iguais, energias de ativação de 104, 154 187 e 60 kJ/mol, desvios padrão de 1,4, 2,9, 1,3 e 11,3 kJ/mol e fator pré-exponencial de 4,14×108, 7,6×1011, 1,84×1013 e 45,77 1/s, respectivamente, na mesma ordem dos componentes considerados. O modelo de deconvolução com funções de Fraser-Suzuki e as Master Plots mostrou que as funções de nucleação com taxas sigmoidais de Avrami-Erofeeev foram adequadas para representar a decomposição dos pseudoextrativos e pseudocelulose, com reação de ordem 1,5 para a pseudo-hemicelulose e de reação de ordem 5 para a pseudolignina. As energias de ativação encontradas foram de 94, 143, 170 e 72 kJ/mol, fator pré-exponencial de 1,91×107, 6,87×1010, 3,53×1011 e 1,63×10³ 1/s, e composição de 0,11, 0,28 0,31 e 0,3 para os pseudoextrativos, pseudo-hemicelulose, pseudocelulose e pseudolignina, respectivamente, resultando em parâmetros inferiores em relação aos modelos de reações de ordem n e DAEM. Com isso, conclui-se que o modelo multicomponente de ordem n apresentou solução bastante satisfatória e requereu computadores com menor poder de processamentoAbstract: This work aims to study the decomposition kinetics of energy cane of specie Saccharum robustum using the thermogravimetry technique. The biomass used was in nature with a mean diameter of 253.5 microns. The thermogravimetric analyzes were performed considering the heating rates of 5, 10, 15 and 20 K/min under nitrogen atmosphere. For the kinetic modeling, global models, with Ozawa-Flynn-Wall, Vyazovkin and Friedman methods showed mean activation energies of 172, 172 and 173 kJ/mol, respectively for conversion range of 0.18 to 0.95. The Master Plots method applied for global models did not identify a single conversion mechanism capable for representing experimental thermal decomposition. Multicomponent models were more adequate to represent the biomass decomposition, being divided in four reactions represented by the extractives, hemicellulose, cellulose and lignin components. Independent parallel reactions scheme (ERPI) with n-order, distributed activated energy model and deconvolution model using Fraser-Suzuki functions were evaluated. The nth-order reaction model presented good agreement with activation energies of 105, 153, 181 and 58 kJ/mol; order reactions of 1.1, 1.3, 1.0 and 3.0; pre-exponential factors of 5×1013, 108, 7.6×1011, 5.81×1012 and 64.7 1/s; and composition of 0.13, 0.2, 0.43, and 0.24, respectively, for each component under consideration. The distributed activation energy model presented values closer to IPRS, with equal compositions, activation energies of 104, 154, 187 and 60 kJ/mol; standard deviations of 1.4, 2.9, 1.3 and 11.3 kJ/mol, pre-exponential factors of 4.14×108, 7.6×1011, 1.84×1013 and 45.77 1/s, respectively, in the same order of considered components. The deconvolution model with Fraser-Suzuki functions and Master plots showed that the que nucleation function with Avrami-Erofeeev sigmoidal rates were satisfactory to represent the decomposition of pseudoextractives and pseudocellulose, 1.5-order reaction model for pseudohemicellulose, and 5th-order pseudolignin reaction. The activation energies found were 94, 143, 170 and 72 kJ/mol, pre-exponential factors of 1.91×107, 6.87×1010, 3.53×1011 and 1.63×10³ 1/s, and composition of 0.11, 0.28, 0.31, and 0.3 for pseudoextractives, pseudocellulose, pseudohemicellulose, and pseudolignin, respectively, resulting in lower parameters in relation to the DAEM and nth order models. Finally, it was concluded that the multicomponent model of nth-order presented a satisfactory solution and required computers with less processing powerMestradoDesenvolvimento de Processos QuímicosMestre em Engenharia Químic

Thermophysical Properties of 1-Propyronitrile-3-alkylimidazolium Bromide Ionic Liquids at Temperatures from (293.15 to 353.15) K

In the present work, a series of 1-propyronitrile-3-alkylimidazolium bromide ionic liquids ([C2CN Cnim]Br, where n = 4, 6, 8, and 10) were synthesized and characterized using Fourier transform infrared spectroscopy (FTIR), NMR, and elemental analysis. Physical properties such as density, viscosity, and refractive index are measured and reported for a temperature range of (293.15 to 353.15) K and at atmospheric pressure. The influence of the alkyl chain on these properties is discussed. The present synthesized ionic liquids show a weak temperature dependency on the thermal expansion coefficient