Optimum Performance of Extractive Desulfurization of Liquid Fuels Using Phosphonium and Pyrrolidinium-Based Ionic Liquids

Abstract

Extractive desulfurization (EDS) of thiophene (T), benzothiophene (BT) and dibenzothiophene (DBT) in simulated fuel using two phosphonium and two pyrrolidinium ionic liquids was investigated. A set of single-factor-at-a-time experiments was carried out to determine factors that significantly affect the EDS process. The single-factor-at-a-time experiments indicate that high sulfur removal (SR) can be achieved using long extraction time (>60 min), high temperature, low fuel-tosolvent ratio (1:4), or large number of extraction stages (N E = 5). However, the single-factor-at-a-time experiment does not take interaction between the factors into consideration and may fail in determining a suitable operating condition. Therefore, a response surface methodology (RSM) based on Box-Behnken design was employed to study and analyze the effects of time, temperature, fuel-to-solvent ratio and their interactions on the EDS process. The ionic liquid, tetrabutylphosphonium methanesulfonate [P 4444 ][MeSO 4 ] yielded the best result with %SR (DBT, BT, T) of 69%, 62%, 61% at the optimum time, temperature, fuel-to-solvent ratio and mixing rate of 15 min, 30 °C, 1:1 and 800 rpm, respectively. A similar performance was obtained during the single-factor-at-a-time experiments but at less favorable conditions indicating the superiority of the statistical approach used in this work in optimizing the liquid−liquid extraction performance.

Synthesis, Characterization and Application of Trihexyl (Tetradecyl) Phosphonium Bromide as a Promising Solvent for Sulfur Extraction from Liquid Fuels

“…Therefore, as the temperature increased to 30 °C, the miscibility increases as the viscosity decreases, and in turn, S-removal increases while beyond 30 °C S-removal decreased, because of the reverse mitigation. 60,62 The results unveil the inverse effect of temperature on the concentration of DBT in the ILs phase.…”

Investigation the effects of cation/anion structure on distribution of Thiophene between IL-rich and Hydrocarbon-rich phases by QSPR approach

“…Literature reviews show that increasing the size of cation/anion of ionic liquid increases the ionic liquid's ability for sulfur removal [1,[3][4][5][6]. Also, the larger alkyl chain of cation/anion and cation symmetry cause more capacity of ionic liquid to sulfur removal [8][9][10][11][12][13][14][15][16][17][18]. It should be noted that an experimental testing approach is very time-consuming, and detecting of appropriate ionic liquid is even unrealistic.…”

“…Most extractive desulfurization studies conduct experimentally for selecting ionic liquids. The structural features of ionic liquid such as cation family, cation alkyl chain length, anion nature, etc., play an important role in removing sulfur compounds from fuels [1,[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Literature reviews show that increasing the size of cation/anion of ionic liquid increases the ionic liquid's ability for sulfur removal [1,[3][4][5][6].…”

Assessment of Pyrrolidinium-Based Ionic Liquid for the Separation of Binary Mixtures Based on Activity Coefficients at Infinite Dilution

“…The utilization of ILs in liquid–liquid extraction − and in extractive distillation , is a promising technology to separate close boiling point mixtures. The relative simple synthesis and low viscosity of pyrrolidinium-based IL are found to add a practical value in various applications, and this also includes possible extraction of sulfur compounds from fuels and observed to reveal high selectivities in (aliphatic/aromatic) extraction processes. − Activity coefficient data for solutes which are soluble in water are very important because water is a universal solvent utilized in various industrial productions for making new chemical compounds. Activity coefficients can be predicted by several methods, but only a limited number of studies reported activity coefficients at infinite dilution for compounds in water, γ 13 ∞ , and very few of them are performed over a range of temperatures. − …”