Excess enthalpies of binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol, and heptane at T = 298.15 K and 313.15 K
Introduction
The use of oxygenated compounds, such as ethers and alcohols, as gasoline-blending agents has been proposed to reduce emissions of new reformulated gasoline. (Ether + alcohol + alkane) are of interest as model mixtures for gasoline in which the alcohol and the ether act as non-polluting, high octane number blending agents [1]. This work continues a study on excess molar enthalpies of mixtures {dibutyl ether (DBE) + 1-butanol + alkane}. DBE is used as blending agent in reformulated gasoline and 1-butanol is a basic component in the synthesis of the ether, and therefore is always contained as an impurity [2]. In a previous paper [3], data for the ternary mixture {DBE + 1-butanol + cyclohexane} at T = 298.15 K have been published. Experimental excess molar enthalpies of the ternary system {DBE + 1-butanol + heptane} and the corresponding binary systems at T = 298.15 K and at T = 313.15 K are reported in this work. Excess molar enthalpies have been measured with a quasi-isothermal flow calorimeter. The experimental data have been fitted using a Redlich–Kister [4] equation, the NRTL [5] and the UNIQUAC [6] models. The values of the standard deviation indicate the agreement between the experimental results and those calculated from the equations.
Section snippets
Experimental section
All the chemicals used here were purchased from Fluka Chemie AG and were of the highest purity available, chromatography quality reagents (of the series puriss p.a.) with a stated purity >99.5%. All reagents were checked by gas chromatography, and the values of purity obtained were >99.6% for DBE, >99.8% for heptane and >99.8% for 1-butanol. The water content for 1-butanol was checked to be less than 0.009%.
Excess molar enthalpies have been measured with a quasi-isothermal flow calorimeter
Results and discussion
The experimental excess molar enthalpies obtained in this work for the binary mixtures (DBE + heptane), (DBE + 1-butanol), and (heptane + 1-butanol) at T = 298.15 K and 313.15 K are listed in TABLE 1, TABLE 2.
For binary systems, there are several models and empirical equations proposed to fit the HE measurements. One of them, the Redlich–Kister equation, is given by equation (1), in which the Ai coefficients are determined by the unweighted least-squares methodBinary systems
Conclusions
Isothermal excess enthalpies at the temperatures of 298.15 K and 313.15 K for the ternary system {DBE (1) + heptane (2) + 1-butanol (3)} and its constituent binary systems were determined by using an isothermal flow calorimeter. All the binary systems show endothermic HE behavior at the measured temperatures. The HE behavior is asymmetric in the binary mixtures containing the alkanol, due to the hydrogen bonding association effect of the alkanol. The two binary systems containing 1-butanol show a
Acknowledgements
This article is part of the Doctoral Thesis of F. Aguilar.
Support for this work came from the Dirección General de Investigación (DGI), Ministerio de Educación y Ciencia, Spain, Projects ENE2006-12620 and ENE2006-13349, and from the Consejería de Educación, Junta de Castilla y León, Spain, Project BU021A08.
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2017, Journal of Chemical ThermodynamicsCitation Excerpt :Amongst the hydrocarbons, linear and branched alkanes, alkenes and aromatics have been considered in previous works. References [4–10] correspond to mixtures with 1-butanol, while references [11,12] refer to 1-propanol. This work concerns with dibutyl ether (DBE), 1-propanol, and the DBE + 1-propanol + cyclohexane, or methylcyclohexane mixtures.
Excess enthalpies of ternary mixtures of (oxygenated additives + aromatic hydrocarbon) mixtures in fuels and bio-fuels: (Dibutyl-ether + 1-propanol + benzene), or toluene, at T = (298.15 and 313.15) K
2015, Journal of Chemical ThermodynamicsCitation Excerpt :The issues with microbial production of bio-propanol are analogous to the issues with microbial production of bio-butanol, so if bio-butanol becomes a more practical biofuel to produce, then bio-propanol will also become more feasible. This work continues a study of our group on excess molar enthalpies of mixtures (ether + alcohol + hydrocarbon) [4–10], where the selected alcohol was the 1-butanol, while reference [11] refers to 1-propanol. This work concerns with Dibutyl ether (DBE), 1-propanol, and the (DBE + 1-propanol + aromatic hydrocarbon) mixtures.
Excess enthalpies of ternary mixtures of oxygenated additives + hydrocarbon mixtures in fuels and bio-fuels: Dibutyl ether (DBE) and 1-butanol and 1-hexene or cyclohexane or 2,2,4 trimethylpentane at 298.15 K and 313.15 K
2013, Journal of Chemical ThermodynamicsCitation Excerpt :The alcohol and the ether act as non-polluting, high octane number blending agents. This work continues a study of our group on excess molar enthalpies HE of DBE and 1-butanol + hydrocarbon mixtures [4–9]. The hydrocarbons selected are representative of the broad spectrum of hydrocarbon components in gasoline: alkanes (heptane), cycloalkanes (cyclohexane), aromatics (benzene), alkenes (1-hexene), branched alkanes (2,2,4-trimethylpentane), branched cycloalkanes (methyl-cyclohexane) and branched aromatics (toluene).
Calorimetric study of the mutual effect in binary and pseudobinary mixtures of some aliphatic alcohols and some cyclic ethers
2012, Journal of Molecular LiquidsCitation Excerpt :The interaction between alkanol and cycloether is generally greater than that of alcohols and branched ether [3]. A large number of thermodynamic experimental results of binary mixtures involving linear or cyclic ether + a polar or nonpolar solvent have been reported [7–12]. Some studies have presented the excess molar enthalpies of binary mixtures of oxane or 1,4-dioxane and alcohols [3,13–15].