Excess Molar Volume along with Viscosity and Refractive Index for Binary Systems of Tricyclo[5.2.1.0^2.6]decane with Five Cycloalkanes

Densities, viscosities, and refractive indices have been measured for the binary system of tricyclo­[5.2.1.0^2.6]­decane with cyclohexane, methylcyclohexane, ethylcyclohexane, butylcyclohexane, or 1,2,4-trimethylcyclohexane at temperatures <i>T</i> = (293.15 to 318.15 K) and pressure <i>p</i> = 0.1 MPa. The excess molar volumes (<i>V</i>_m^E), the viscosity deviations (Δη), and the refractive index deviations (Δ<i>n</i>_D) are then calculated. The changes of <i>V</i>_m^E and Δη with the composition are fitted to the Redlich–Kister equation. The values of density, viscosity, and refractive index increase continuously with the increase of mole fraction of tricyclo­[5.2.1.0^2.6]­decane and decrease with the rise of temperature. The <i>V</i>_m^E and Δη are all negative over the whole composition range for these five binary systems. The changes of <i>V</i>_m^E and Δη are discussed from the points of view of molecular interactions in the binary systems

Density, Viscosity, Surface Tension, and Refractive Index for Binary Mixtures of 1,3-Dimethyladamantane with Four C₁₀ Alkanes

For a comprehensive understanding of the properties of 1,3-dimethyladamantane (1,3-DMA) as a new potential candidate of high energy-density hydrocarbon fuels, densities, viscosities, surface tensions, and refractive indices for binary mixtures of 1,3-DMA with each of four C₁₀ alkanes, <i>n</i>-decane, butylcyclohexane, decalin, and <i>exo</i>-tetrahydrodicyclopentadiene (JP-10), are determined over the whole composition range at different temperatures ranging from (293.15 to 363.15) K and atmospheric pressure (0.1 MPa). The excess molar volume (<i>V</i>_m^E), the viscosity deviation (Δη), the surface tension deviation (Δγ), and the refractive index deviation (Δ<i>n</i>_D) for these binary systems are calculated. All of the <i>V</i>_m^E values are negative over the whole composition range for these systems, and they show slight changes against the temperature. The Δη values for the systems except 1,3-DMA + JP-10 are negative, and the absolute values decrease obviously with rising temperature. The Δγ gives clearly negative values for the system of 1,3-DMA + <i>n</i>-decane and shows small values near zero for the other systems. Negligible values of Δ<i>n</i>_D indicate that the refractive indices show nearly linear additions from those of two components for the binary mixtures. The results could provide important reference information for the development and performance of new high energy-density hydrocarbon fuels

Piperazinium-Based Ionic Liquids with Lactate Anion for Extractive Desulfurization of Fuels

Three kinds of piperazinium-based room-temperature ionic liquids (RTILs), namely, <i>N</i>-methylpiperazinium lactate ([C₁pi]­[Lac]), <i>N</i>-ethylpiperazinium lactate ([C₂pi]­[Lac]), and <i>N</i>,<i>N</i>′-dimethylpiperazinium dilactate ([C₁C₁pi]­[Lac]₂), have been synthesized by the direct reaction of <i>N</i>-alkyl-substituted piperazines and lactate acid. Together with 1,1,3,3-tetramethylguanidinium lactate ([TMG]­[Lac]), they are employed as new extractants for removing aromatic sulfur compounds, thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), and 4-methyldibenzothiophene (4-MDBT), from various hydrocarbon fuels. The effects of the temperature, extraction time, and amount of ionic liquid (IL) on the sulfur removal are investigated systematically. The mutual solubility measurements show that the ILs are dissolved in <i>n</i>-heptane with the mass fraction less than 0.01 at 30 °C. The solubility values of 93 gasoline in the ILs are observed with the following sequence: [C₁C₁pi]­[Lac]₂ (0.007 in mass fraction) < [C₁pi]­[Lac] (0.014 in mass fraction) < [TMG]­[Lac] (0.017 in mass fraction) < [C₂pi]­[Lac] (0.070 in mass fraction), and the sulfur distribution coefficient follows the order: [TMG]­[Lac] (1.08 in mass fraction) > [C₂pi]­[Lac] (0.98 in mass fraction) > [C₁pi]­[Lac] (0.78 in mass fraction) > [C₁C₁pi]­[Lac]₂ (0.53 in mass fraction) for 93 gasoline. Selectivity between TS and toluene is observed higher than 4 with the following sequence: [TMG]­[Lac] (13.19 in mass fraction) > [C₁pi]­[Lac] (10.59 in mass fraction) > [C₂pi]­[Lac] (7.12 in mass fraction) > [C₁C₁pi]­[Lac]₂ (4.94 in mass fraction), revealing that these ILs are more preferable to extract TS than toluene from hydrocarbon fuels. The used ILs can be recycled without a significant decrease of desulfurization activity after extraction 5 times. These fundamental results hopefully provide useful information for future commercialization and practical desulfurization