The role of ionic liquids in desulfurization of fuels: A review
TL;DR: In this article, the authors discuss the merits and drawbacks of the major areas of alternative desulfurization technologies, including bio-diesel, adsorption, extractive and oxidative desulurization, with special emphasis on the role of ionic liquids as distinctive multi-task fluids.
Abstract: Sulfur compounds in transportation fuels are a pressing issue currently due to the more stringent limits of sulfur content. Sulfur compounds lead to SOx emissions which cause many environmental and health problems. The conventional refinery desulfurization process, hydrodesulfurization (HDS), is conducted at elevated temperatures and pressures, using expensive hydrogen gas and catalysts. This review aims to discuss the merits and drawbacks of the major areas of alternative desulfurization technologies, including biodesulfurization, adsorption, extractive and oxidative desulfurization, with special emphasis on the role of ionic liquids (ILs) as distinctive multi-task fluids. With the rapid development of ILs in the last decades, more effective and reliable desulfurization techniques are foreseeable.
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TL;DR: In this article, metal-organic frameworks (MOFs)-based and MOF-derived nanohybrid materials were suggested as a good catalyst for ODS of fuels, and removal of NCCs via oxidation with MOFs-derived catalyst was also reported even though the technique is just emerging.
Abstract: Removal of sulfur- and nitrogen-containing compounds (SCCs and NCCs) from commercial fuel is very important since those impurities can cause various problems including catalyst deactivation and acid rain. Because of the limitations of the conventional refinery methods, development of a new method such as oxidative desulfurization (ODS) is highly desirable. Metal-organic frameworks (MOFs)-based and MOF-derived nanohybrid materials were suggested as a good catalyst for ODS of fuels. Moreover, removal of NCCs via oxidation with MOF-derived catalyst was also reported even though the technique is just emerging. Therefore, it is required to analyze the reported results; and more importantly to suggest a new research direction; and finally, to estimate the possibility of new desulfurization/denitrogenation technology that might replace/compensate studied technologies. This review might be quite beneficial not only to accumulate or understand the reported results but also to develop new efficient catalysts for the probable commercialization of the ODS/ODN technology.
142 citations
TL;DR: In this article, a review of the recent advances of the recovery and purification of ionic liquids from solutions is presented, mainly focused on recent advances in ionic liquid recovery.
Abstract: With low melting point, extremely low vapor pressure and non-flammability, ionic liquids have been attracting much attention from academic and industrial fields. Great efforts have been made to facilitate their applications in catalytic processes, extraction, desulfurization, gas separation, hydrogenation, electronic manufacturing, etc. To reduce the cost and environmental effects, different technologies have been proposed to recover the ionic liquids from different solutions after their application. This review is mainly focused on the recent advances of the recovery and purification of ionic liquids from solutions. Several methods for recovery of ionic liquids including distillation, extraction, adsorption, membrane separation, aqueous two-phase extraction, crystallization and external force field separation, are introduced and discussed systematically. Some industrial applications of ionic liquid recovery and purification methods are selected for discussion. Additionally, considerations on the combined design of different methods and process optimization have also been touched on to provide potential insights for future development of ionic liquid recovery and purification.
141 citations
TL;DR: In this article, the authors focused on the heavy fuels initially containing more than 0.5 wt.%S and upgraded by the ODS process, and discussed their viability when applied to high sulfur content, high viscosity, and high boiling point feeds.
Abstract: The demand for clean fuels is increasing throughout the world, with more stringent environmental regulations for transportation fuels including marine fuels, particularly regarding their sulfur content. Moreover, the quality of crude oil and derived petroleum cuts is getting lower while fossil fuels are still in high demand. Heavy oils are characterized by high sulfur content where most sulfur is found in bulky thiophenic structures difficult to remove using conventional high pressure hydrodesulfurization process. However they appeared more reactive in oxidative desulfurization (ODS) process, carried out at mild conditions without hydrogen pressure. This review focuses for the first time on the heavy fuels initially containing more than 0.5 wt.%S and upgraded by the ODS process. Different attractive approaches of the literature towards ODS are reported using homogeneous and heterogeneous catalysis. Recent developments in ODS assisted with ultrasound technology and the use of ionic liquid to enhance ODS efficiency will be fully detailed and discussed to better understand their viability when applied to high sulfur content, high viscosity, and high boiling point feeds.
140 citations
TL;DR: Deep eutectic solvents (DESs), a less toxic solvent than ionic liquids (ILs) discovered in 2001 have been actively researched as a substitute solvent since 2013 as mentioned in this paper.
120 citations
TL;DR: The M DC-C, even with a lower TiO2 content than that of MDC-P, showed an outstanding catalytic performance, especially with a very low catalyst dose and a low activation energy for the oxidation of dibenzothiophene.
Abstract: A new metal–organic framework (MOF) composite consisting of Ti- and Zn-based MOFs (ZIF-8(x)@H2N-MIL-125; in brief, ZIF(x)@MOF) was designed and synthesized. The pristine MOF [H2N-MIL-125 (MOF)]- and an MOF-composite [ZIF(30)@MOF]-derived mesoporous carbons consisting of TiO2 nanoparticles were prepared by pyrolysis (named MDC-P and MDC-C, respectively). MDC-C showed a higher surface area, larger pore sizes, and larger mesopore volumes than MDC-P. In addition, the TiO2 nanoparticles on MDC-C have more uniform shapes and sizes and are smaller than those of MDC-P. The obtained MDC-C and MDC-P [together with MOF, ZIF(30)@MOF, pure/nanocrystalline TiO2, and activated carbon] were applied in the oxidative desulfurization reaction of dibenzothiophene in a model fuel. The MDC-C, even with a lower TiO2 content than that of MDC-P, showed an outstanding catalytic performance, especially with a very low catalyst dose (i.e., a very high quantity of dibenzothiophene was converted per unit weight of the catalyst), fast ...
101 citations
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12,178 citations
TL;DR: Rogers and Seddon as discussed by the authors reviewed recent progress on developing new ionic liquid solvents for use in chemical synthesis, catalysis, fuel cells, and other applications.
Abstract: Ionic liquids are composed entirely of ions. Because of the wide range of possible binary and ternary ionic liquids, they offer a potentially wide range of solvent properties. In their Perspective,
Rogers and Seddon
review recent progress on developing new ionic liquid solvents for use in chemical synthesis, catalysis, fuel cells, and other applications. Ionic liquids are considered advantageous not only because of their versatility but also for their "green" credentials, although it is important to remember that not all ionic liquids are environmentally benign. One industrial process has been reported, and others may not be far behind. The authors conclude that in the next decade, ionic liquids are likely to replace conventional solvents in many applications.
3,687 citations
Book•
01 Jan 2002
TL;DR: The early years of Ionic liquid production were covered in this article, where a new generation of soluble supports for Supported Organic Synthesis (SPOS) was proposed. But this support was not applied to the task-specific Ionic liquids.
Abstract: Preface A Note From The Editors THE EARLY YEARS OF IONIC LIQUIDS SYNTHESIS AND PURIFICATION Synthesis Quality Aspects and other Questions Related to Commercial Ionic Liquid Production Synthesis of Task-specific Ionic Liquids PHYSICO-CHEMICAL PROPERTIES Melting Points Viscosity and Density Solubility and Solvation in Ionic Liquids Gas Solubilities Polarity Electrochemistry STRUCTURE AND DYNAMICS Order in the Liquid State and Structure Computational Modelling of Ionic Liquids Translational Diffusion Molecular Reorientational Dynamics ORGANIC SYNTHESIS Ionic Liquids in Organic Synthesis: Effects on Rate and Selectivity Stoicheiometric Organic Reactions and Acid-catalysed Reactions in Ionic Liquids Transition Metal Catalysis in Ionic Liquids Ionic Liquids in Multiphasic Reactions Task Specific Ionic Liquids (TSILs): A New Generation of Soluble Supports for Supported Organic Synthesis (SPOS) Supported Ionic Liquid Phase Catalysts Multiphasic Catalysis Using Ionic Liquids in Combination with Compressed CO2 INORGANIC SYNTHESIS Directed Inorganic and Organometallic Synthesis Making of Inorganic Materials by Electrochemical Methods Ionic Liquids in Material Synthesis: Functional Nanoparticles and Other Inorganic Nanostructures POLYMER SYNTHESIS IN IONIC LIQUIDS BIOCATALYTIC REACTIONS IN IONIC LIQUIDS INDUSTRIAL APPLICATIONS OF IONIC LIQUIDS CONLUDING REMARKS AND OUTLOOK
3,423 citations
TL;DR: It is demonstrated that some selected families of commonly used aprotic ionic liquids can be distilled at 200–300 °C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.
Abstract: It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes, fuel cells and batteries, and new composite materials. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200-300 degrees C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.
1,900 citations
TL;DR: A series of novel air and water stable low melting salts based upon the 1-ethyl-3methylimidazolium cation (EtMeim+) have been prepared and characterized.
Abstract: A series of novel air and water stable low melting salts based upon the 1-ethyl-3-methylimidazolium cation (EtMeim+) have been prepared and characterized; two salts, [EtMeim]BF4 and [EtMeim]MeCO2, are liquids under ambient conditions.
1,561 citations