Jean-Noël Jaubert

Extraction of benzene or thiophene from n-heptane using ionic liquids. NMR and thermodynamic study.

In this work, (1)H and (31)P NMR spectroscopy were used to study the interactions between thiophene or benzene with three imidazolium based ionic liquids (ILs): 1-butyl-3-methylimidazolium tetrafluoroborate, 1,3-dimethylimidazolium methylphosphonate, and 1-butyl-3-methylimidazolium thiocyanate. NMR study indicates that solubility of thiophene or benzene in ionic liquid strongly depends on the structure of the ionic liquid. Structural organizations of such systems have been proposed. From these results, liquid-liquid equilibria (LLE) measurements of ternary mixtures containing benzene or thiophene with n-heptane and these ILs were carried out at 298.15 K in order to check the ability of these ILs to act as extractive solvents.

High Carbon Dioxide Solubilities in Imidazolium-Based Ionic Liquids and in Poly(ethylene glycol) Dimethyl Ether

This work is focused on the possible capture of carbon dioxide using ionic liquids (ILs). Such solvents are gaining special attention because the efficiency of many processes can be enhanced by the judicious manipulation of their properties. The absorption of greenhouse gases can be enhanced by the basic character of the IL. In this work, these characteristics are evaluated through the study of the gas-liquid equilibrium of four imidazolium-based ILs: 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF(4)], 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN], 1,3-dimethylimidazolium methylphosphonate [DMIM][MP], and 1,3-diethoxyimidazolium bis(trifluoromethylsulfonyl)imide [(ETO)(2)IM][Tf(2)N] with CO(2) at temperatures up to 373 K and pressures up to 300 bar. Solubility of carbon dioxide in poly(ethylene glycol) dimethyl ether, component of selexol, was also measured to evaluate the captures efficiency of ionic liquids. Experimental data indicate that 67 to 123 g of CO(2) can be absorbed per kg of ionic liquid and 198 g per kg of poly(ethylene glycol) dimethyl ether.

Reducing of Nitrous Oxide Emissions Using Ionic Liquids

This work is focused on the possible capture of nitrous oxide and more precisely protoxide using ionic liquids (ILs). ILs are gaining special attention since the efficiency of many processes can be enhanced by the judicious manipulation of their properties. The absorption of greenhouse gases can be enhanced by the basic character of the IL. In this work, these characteristics are evaluated through the study of the gas-liquid equilibrium of five imidazolium-based ILs: 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]), 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), 1,3-dimethylimidazolium methylphosphonate ([DMIM][MP]), 1,3-diethoxyimidazolium bis(trifluoromethylsulfonyl)imide ([(ETO)(2)IM][Tf(2)N]), and 1,3-dihydroxyimidazolium bis(trifluoromethylsulfonyl)imide ([(OH)(2)IM][Tf(2)N]) with N(2)O at temperatures up to 373 K and pressures up to 300 bar. Experimental data indicate that 44-105 g of N(2)O can be absorbed per kilograms of IL.

Ethanol and Distillate Blends—A Thermodynamic Approach to Miscibility Issues: Part 2—The Influence of Water

In recent years, the quest for sustainable primary energies has increased the potential interest of biogenic/fossil fuels mixes. As an example, ethanol is used as a gasoline extender to both partly substitute hydrocarbons and increase octane number while improving vehicle emissions. In a previous paper (GT2010-22126), it has been shown that ethanol and gasoil are able to blend and form homogeneous solutions only in limited proportion ranges, due to their markedly different physical and chemical properties. However the incorporation of small amounts of water in ethanol dramatically decreases this already narrow miscibility domain. Indeed, in function of the temperature, such ternary mixtures often give rise to liquid-liquid equilibria i.e. to two separated phases that are respectively lipophilic and hydrophilic. A key parameter is thus the Minimum Miscibility Temperature, i.e. the temperature above which ethanol, water and gasoil become completely miscible. On another hand, commercial gasoils do not constitute a single product but display worldwide a large range of compositions that influence the stability of these ternary blends. In this context, an investigation program intended to characterize and predict the stability of ternary ethanol + water + gasoil blends has been carried out by the LRGP laboratory (Laboratoire Reactions et Genie des Procedes). The approach is based on a thermodynamical, theoretical calculation of the liquid-liquid phase diagrams formed by ethanol, water and a mixture of various hydrocarbons representative of the diesel oil pool using the group-contribution concept. The basic idea is that whereas there are thousands of chemical compounds, the number of functional groups that constitute these compounds is much smaller. The work relies on the experimentally verified theory that a physical property of a fluid can be expressed as the sum of contributions made by molecule’s functional groups, which allows correlating the properties of a very large number of substances in terms of a much smaller number of parameters that represent the contributions of individual groups. This work shows the huge influence exerted by the water content of ethanol on the shape of the liquid-liquid phase diagram and on the value of the Minimum Miscibility Temperature (MMT). As seen in our previous paper, the paraffinic, aromatic or naphthenic character of the fossil fraction, also considerably influences the value of the MMT. Calculations were performed with a water content varying between 1 and 10%. This study concludes that the MMT expressed in kelvins is generally multiplied by two when the water content rises from 1 to 10%.© 2011 ASME

Ethanol and Distillate Blends: A Thermodynamic Approach to Miscibility Issues

In the recent years, the quest for an ever wider cluster of sustainable primary energies has prompted an increasing number of attempts to combine the emission sobriety of bio fuels with the energy density advantage of fossil fuels. A number of compositions incorporating hydrocarbons, ethanol and in some cases limited amounts of water have been proposed, especially in the forms of micro emulsions, with a variable success. Indeed due to markedly different physical and chemical properties, ethanol and gasoil are able to blend and form homogeneous solutions only in limited proportion ranges. Indeed, such mixtures often give rise to liquid-liquid equilibrium. A key parameter is thus the Minimum Miscibility Temperature (MMT), i.e. the temperature above which ethanol and gasoil become completely miscible. In fact, commercial gasoils do not constitute a monolithic product but display in the contrary a large span of compositions that influence the stability of these blends. In this context, the LRGP laboratory (Laboratoire Reactions et Genie des Procedes) has undertaken an investigation program intended to understand the factors underlying the stability of ethanol/gasoil blends. The approach is based on the calculation of the liquid-liquid phase diagrams formed by anhydrous ethanol and a mixture of various hydrocarbons representative of the diesel oil pool using the group contribution concept. Indeed, for correlating thermodynamic properties, it is often convenient to regard a molecule as an aggregate of functional groups; as a result, some thermodynamic properties (heat of mixing, activity coefficients) can be calculated by summing group contributions. In this study, the universal quasichemical functional group activity coefficient (UNIFAC) method has been employed as it appears to be particularly useful for making reasonable estimates for the studied non ideal mixtures for which data are sparse or totally absent. In any group-contribution method, the basic idea is that whereas there are thousands of chemical compounds of interest in chemical technology, the number of functional groups that constitute these compounds is much smaller. Therefore, if we assume that a physical property of a fluid is the sum of contributions made by the molecule’s functional groups, we obtain a possible technique for correlating the properties of a very large number of fluids in terms of a much smaller number of parameters that characterize the contributions of individual groups. This paper shows the large influence exerted by the paraffinic, aromatic and naphthenic character of the gasoil but also the sulfur content of the fossil fraction on the shape of the liquid-liquid phase diagram and on the value of the minimum miscibility temperature.Copyright

Ethanol-Hydrocarbon Blend Vapor Prediction

In the volatile fuel price environment of today, the quest for alternative fuels has become a heavy and long term trend in power generation worldwide. Incorporating alternative fuels in gas turbine installations raises multiple engineering questions relating to combustion, emissions, on-base and auxiliary hardware capability, safety etc. In 2008, GE carried out a field test aimed at characterizing the combustion of ethanol in a naphtha fuelled gas turbine plant. The testing strategy has been to locally prepare and burn ethanol-naphtha blends with a fraction of ethanol increasing from 0 to nearly 100%. During the engineering phase prior to this field test, it appeared necessary to develop a sufficient knowledge on the behavior of ethanol-hydrocarbon blends in order to establish the safety analysis and address in particular the risks of (i) a potential uncontrolled ignition event in the air blanket of fuel tanks and (ii) flash vaporization of a potential fuel pond in a confined environment. Although some results exist in the car engine literature for ethanol-gasoline blends, it was necessary to take into account the specificities of gas turbine applications, namely (i) the much greater potential ethanol concentration range (from 0 to 100%) and (ii) the vast composition spectrum of naphtha likely to generate a much larger Reid Vapor Pressure envelope as compared with automotive applications. In order to fulfill the safety needs of this field test, the “Laboratoire de Thermodynamique des Milieux Polyphases” (LTMP) of Nancy, France has developed a thermodynamic model to approach the vaporization equilibria of ethanol-hydrocarbons mixtures with variable ethanol strength and naphtha composition. This model, named PPR78, is based on the 1978 Peng-Robinson equation of state and allows the estimation of the thermodynamic properties of a multicomponent mixture made of ethanol and naphtha compounds by using the group contribution concept. The saturation equilibrium partial pressure of such fluids in the various situations of relevance for the safety analysis can thus be calculated. The paper reports the elaboration of this model and illustrates the results obtained when using it in different safety configurations.© 2009 ASME