Extractive Desulfurization and Denitrogenation of Fuels Using Ionic Liquids

Abstract

Two types of ionic liquids, 1-alkyl-3-methylimidazolium [AMIM] tetrafluoroborate and hexafluorophosphate and trimethylamine hydrochloride (AlCl 3 -TMAC), were demonstrated to be potentially applicable for sulfur removal from transportation fuels. EMIMBF 4 (E ) ethyl), BMIMPF 6 (B ) butyl), BMIMBF 4 , and heavier AMIMPF 6 showed high selectivity, particularly toward aromatic sulfur and nitrogen compounds, for extractive desulfurization and denitrogenation. The used ionic liquids were readily regenerated either by distillation or by water displacement of absorbed molecules. The absorbed aromatic S-containing compounds were quantitatively recovered. Organic compounds with higher aromatic π-electron density were favorably absorbed. Alkyl substitution on the aromatic rings was found to significantly reduce the absorption capacity, as a result of a steric effect. The cation and anion structure and size in the ionic liquids are important parameters affecting the absorption capacity for aromatic compounds. At low concentrations, the N-and S-containing compounds were extracted from fuels without mutual hindrance. AlCl 3 -TMAC ionic liquids were found to have remarkably high absorption capacities for aromatics.

Ionic Liquids as Surfactants – Applications as Demulsifiers of Petroleum Emulsions

“…As described throughout this book, ILs present exceptional properties such as high solvent abilities, negligible vapor pressures, extremely high electrical conductivities, chemical and thermal stability [34][35] that have been exploited in applications as diverse as in organic synthesis [36][37], catalysis [38][39], biocatalysis [40][41], separations [42], extraction [43], dissolution [44], polymerization reactions [45] and electrochemistry [46]. In petroleum industry, ILs have found wide applications as corrosion inhibitors [14,47], as inhibitors of asphaltene precipitation [48] and for removing pollutants from refineries feedstocks [13].…”

Ionic Liquids in Chemical Analysis

“…The application of mild process conditions (ambient pressure and temperature) and the fact that no hydrogen is needed are additional advantages compared to HDS. 4 ], and heavier trimethylamine hydrochloride (AlCl 3 -TMAC) showed high selectivity, particularly toward aromatic sulfur and nitrogen compounds, for extractive desulfurization and denitrogenation (58). The used ILs were readily regenerated either by distillation or by water displacement of absorbed molecules.…”

Theoretical Study on Interactions between N-Butylpyridinium Nitrate and Thiophenic Compounds

“…13 Zhang et al also stated that the sulfur compounds with a higher density of aromatic π-electron are favorably absorbed by ionic liquids. 42,43 The relatively large differences in the partition coefficients of the individual sulfur compounds may be due to the difference of aromatic π-electron density of sulfur compounds. These results suggested that the extractive performance becomes better with the increase of the aromatic π-electron density.…”