Experimental and Modeling Density and Surface Tension of 1, 2-Dimethylbenzene with Alkanes at 298.15k
Abstract
Experimental density and surface tension of 1,2-dimethylbenzene with octane, nonane and decane have been obtained at 298.15K and atmospheric pressure. This work increases the available experimental information regarding this kind of mixtures useful in the fuel field. The excess molar volume and the surface tension deviation have been correlated by Redlich-Kister polynomial equation. Besides, density of binary systems has been predicted and correlated with Nitta-Chao group contribution and ERAS models respectively while the surface tension deviation have been predicted with HSIS and HSEG and SE models. Finally, a comparison about the behavior of excess volume molar and deviation surface tension between dimethylbenzene isomers and alkanes is presented.
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Introduction
Methylbenzenes occur in small quantities in naphtha and higher boiling fractions of petroleum. Those presently of commercial importance are toluene, 1,2-dimethylbenzene (o-xylene), 1,4-dimethylbenzene (p-xylene), and to a much lesser extent 1,3-dimethylbenzene (m-xylene). Particularly, 1,2-dimethylbenzene is mainly used to produce phthalic anhydride for plasticizers. The primary sources of xylenes are reformates from catalytic reforming units, gasoline from catcraking, and pyrolysis gasoline from steam reforming of naphtha and gas oils. Solvent extraction is used to separate these aromatics from the reformate mixtures [1]. For this reason, physical properties of pure and mixtures liquids containing aromatic and aliphatic compounds and their dependence with composition are very important basic data for petrochemical industry
Some experimental data of density and surface tension are available in literature for 1,4-dimethylbenzene and alkanes [2-4]. In this sense, in previous works we have also studied high pressure density for 1,4-dimethylbenzene pure component and its binary mixtures with dimethyl carbonate, diethyl carbonate, n-octane and n-decane at (288.15, 298.15 and 308.15) K and (0.1, 5, 10, 20, 30 and 40) MPa [5]. However, from our knowledge only a few experimental data about excess molar volume have been reported by Cáceres Alonso and Delgado[6] for 1,2-dimethylbenzene – octane binary mixtures, while excess molar volume and density have been reported by Cáceres Alonso and Delgado [6] and Chevalier et al.[7] respectively for 1,2-dimethylbenzene – decane binary mixtures. For this reason, in this work, experimental data of density and surface tension of 1,2-dimethylbenzene with octane, nonane and decane at 298.15K and atmospheric pressure are presented. These behaviors are compared with those showed by 1,4-dimethylbenzene and 1,3-dimethylbenzene with alkanes.
Redlich-Kister polynomial equation has been used to correlate the excess molar volume and the surface tension deviation. Moreover, Nitta-Chao group contribution and ERAS models have been used to predict and correlate the density data of dimethylbenzene – alkanes systems respectively, while, HSIS, HSEG and SE models have been used in the predictions of the surface tension deviation.
Conclusion
Density and surface tension of 1,2-dimethylbenzene + octane, nonane or decane binary mixtures at 298.15K and atmospheric pressure are presented. Excess molar volume and surface tension deviation have been calculated and correlated by RedlichKister polynomial equation. These data allow comparing excess volume molar and surface tension deviation between the different dimethylbenzene isomers + alkane binary mixtures.
No differentiation between the different isomers of dimethylbenzene family is obtained with Nitta-Chao model, while, ERAS model can reproduce correctly all the systems studied in this work. HSIS, HSEG and SE models predict qualitative the surface tension deviation in 1-2 dimethylbenzene + alkanes binary mixtures.