Xiao-Ming Peng

Desulfurization of Diesel Fuel by Extraction with [BF4]−-based Ionic Liquids

Abstract The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]−-based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 : 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.

Separation of ionic liquids from dilute aqueous solutions using the method based on CO2 hydrates

Abstract Ionic liquids (ILs) have been regarded as the potential novel solvents for improved analytical- and process-scale separation methods. The development of methods for the recovery of ILs from aqueous solutions to escape contamination and recycle samples will ultimately govern the viability of ILs in the future industrial applications. Therefore, in this paper a new method for separation of ILs from their dilute aqueous solutions and simultaneously purification of water was proposed on the basis of the CO2 hydrate formation. For illustration, the dilute aqueous solutions with concentrations of ILs ranging from 2 × 10−3 mol% to 2 × 10−1 mol% were concentrated. The results show that the separation efficiency is very impressive and that the new method is applicable to aqueous solutions of both hydrophobic and hydrophilic ILs. Compared to the literature separation method based on the supercritical CO2, the new method is applicable to lower concentrations, and more importantly, its operation condition is mild.

Effect of 1-butyl-3-methylimidazolium tetrafluoroborate on the formation rate of CO2 hydrate

Abstract The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 mim][BF 4 ]) on the formation rates of CO 2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formation rates of CO 2 hydrates. As compared to those of pure water, the data of phase equilibrium changed greatly. The effects of pressure, temperature, and the concentration of [C 4 mim][BF 4 ] aqueous solution on the formation rates of CO 2 hydrates were investigated. With a constant concentration of [C 4 mim][BF 4 ], the rate of gas consumption was enhanced with the lowering of experimental temperature. However, a decrease in pressure exerted an opposite effect on the rate of gas consumption. Moreover, the addition of [C 4 mim][BF 4 ] raised the equilibrium pressure of hydrate formation at the same temperature.

Prediction of density and viscosity of ternary systems [C2q]Br+[C4q]Br+H2O, [C2q]Br+[C6q]Br +H2O, and [C4q]Br+[C6q]Br+H2O at different temperatures using their binary subsystems data

The simple equations for prediction of the density and viscosity of mixed electrolyte solutions were extended to the related properties of mixed ionic liquid solutions. The density and viscosity were measured for ternary solutions [C2q]Br(N-ethylquinolinium bromide)+[C4q]Br (N-butylquinolinium bromide)+H2O, [C2q]Br+[C6q]Br(N-hexylquinolinium bromide)+H2O, and [C4q]Br+[C6q]Br+H2O and their binary subsystems [C2q]Br+H2O, [C4q]Br+H2O, and [C6q]Br+H2O at 15, 20 and 25 °C, respectively. The results were used to test the predictability of the extended equations. The comparison results show that these simple equations can be used to predict the density and viscosity of the mixed ionic liquid solutions from the properties of their binary subsystems of equal ionic strength.

Densities and Conductivities of Aqueous N,N,N-Alkyloctyldimethylammonium Chloride at Different Temperatures

The simple equations for predictions of the density and conductivity of mixed electrolyte solutions were extended to the related properties of mixed ionic liquid solutions. The densities and conductivities were measured for the ternary solutions OOAC (N,N,N-dioctyldimethylammonium chloride) + OPAC (N,N,N-octylpentyldimethylammonium chloride) + H2O, OOAC + N,N,N-octylbutyldimethylammonium chloride (OBAC) + H2O, OPAC + OBAC + H2O and their corresponding binary subsystems OOAC + H2O, OPAC + H2O, and OBAC + H2O at (298.15, 303.15, and 308.15) K, respectively. The results were used to test the predictability of the extended equations. Comparison of the results shows that these simple equations can be used to predict the density and conductivity of the mixed ionic liquid solutions from the properties of their binary subsystems of equal ionic strength.

Decomposition Kinetics for Formation of CO2 Hydrates in Natural Silica Sands

Abstract The decomposition kinetics for formation of CO 2 hydrates in 90 cm 3 wet natural silica sands were studied systematically using the depressurization method at the temperatures ranging from 273.2 to 277.2 K and the pressures from 0.5 to 1.0 MPa. The effects of temperature, pressure, particle diameter, porosity, and salinity of formation water on the decomposition kinetics were investigated. The results show that the dissociation percentage increases as temperature increases or as the initial decomposition pressure decreases. An increase in porosity or a decrease in particle diameter of silica sands accelerates the decomposition. Increasing the salinity of the formation water gives rise to a faster decomposition. However, a combination of the present results with the observations in literature reveals that the effect of the coexisting ionic solute depends on its chemical structure.

Viscosities of ternary systems Y(NO3)3+La(NO3)3+H2O, La(NO3)3+Ce(NO3)3+H2O,La(NO3)3+Nd(NO3)3+H2O and their binary subsystems at different temperatures

Viscosities were measured for the ternary systems Y(NO3)3+La(NO3)3+H2O,La(NO3)3+Ce(NO3)3+H2O,and La(NO3)3+Nd(NO3)3+ H2O and their binary subsystems Y(NO3)3+H2O,La(NO3)3+H2O,Ce(NO3)3+H2O,and Nd(NO3)3+H2O at 293.15,298.15 and 308.15 K.The results were used to test the applicability of simple equations for the viscosity of the mixed solutions.The predictions agreed well with measured values,implying that the viscosities of the examined electrolyte solutions could be related to those of their constituent binary solutions using these simple equations.