Ionic liquid sulfide

Odourless and non-volatile organosulfur compounds grafted to an imidazolium ionic liquid scaffold has been synthesized. The sulfoxides have been used for an efficient oxidation of primary allylic and benzylic alcohols into aldehydes and secondary alcohols to ketones under Swern oxidation conditions and the corresponding sulfides can be recovered and recycled.110... 

The following section focuses on the quatemization reaction of 1-alkylimidazoles since these are the most commonly used starting materials for ionic liquids and have dominated ionic liquids research over the last twenty years. However, the general method for the quatemization reaction is similar for pyridines [13], isoquinolines [14], 1-methylpyrrolidine [15], trialkylamines [16], phosphines [17] and sulfides [18]. 

Chen et al. reported a more environmentally friendly version of the Pictet-Spengler reaction <06H1651>. In this report, a series of 2-phenylsulfonyl-l,2,3,4-tetrahydroisoquinoline-1-carboxylic acid ethyl ester derivatives 114 were synthesized in good yields through the cyclization of A-phenylsulfonyl-P-phenethylamines 115 with a-acyl sulfide 116 using phenyliodine(III) bis(trifluoroacetate) (PIFA) in ionic liquid ([bminjPFJ. The use of the ionic liquid allows for a simple purification and [bmin]PF can conveniently be recycled. 

Potential for Hydrogen Sulfide Removal Using Ionic Liquid Solvents... 

Heintz YJ, Sehabiague L, Morsi BI et al (2009) Hydrogen sulfide and carbon dioxide removed from dry fuel gas streams using an ionic liquid as a physical solvent. Energy Fuel 23 4822 830... 

PomeUi CS, Chiappe C, Vidis A et al (2007) Influence of the interaction between hydrogen sulfide and ionic liquids on solubility experimental and theoretical investigation. J Phys Chem B 111 13014-13019... 

The ionic liquid-supported sulfoxide 7 as a recoverable and recyclable r ent for the Swem oxidation of various alcohols has also been proposed. The carbonyl product was easily separated from the ionic liquid anchored sulfide 6 by simple phase separation with diethyl ether after Swem oxidation. As shown in Scheme 14.60,... 

Chapter 6 discusses the progress, advantages, challenges, and opportunities associated with the removal of hydrogen sulfide using ionic liquid solvents. 

Water can be used as the solvent in the presence of added surfactants. Reactions in ionic liquids and supercritical fluids are also feasible. A variety of reagents promote cyclization, which can be achieved at room temperature. Examples of compounds that promote and accelerate the reaction include A -methylmorpholine A -oxide, trimethylamine A -oxide, phosphine oxides, dimethylsulfoxide, alkyl methyl sulfides, molecular sieves, and lithium perchlorate. A comparison of a few promoters is seen in Scheme 246. Promoters... 

Various primary and secondary alcohols can be oxidized to aldehydes and ketones with the ion-supported [bis(acyloxy)iodo]arene 99 in the ionic liquid [emim]+[BF4] (l-ethyl-3-methylimidazolium tetrafluorobo-rate) in the presence of bromide anion [94], or in water in the presence of ion-supported TEMPO [97]. Under similar conditions reagent 99 can be used for mild, efficient, highly selective and environmentally friendly oxidation of aliphatic and aromatic sulfides to sulfoxides in excellent yields [98]. This reaction is compatible with hydroxyl, nitrile, methoxy, carbon-carbon double bonds and ester functionalities. The analogous pyrrolidinium-derived ion-supported [bis(acyloxy)iodo]arenes are efficient oxidants of alcohols to carbonyl compounds in the presence of TEMPO [99]. 

Preparation and application of a new class of catalytic ionic liquids containing chiral W(V1) anions has been described. The hydrophobic ionic liquid [P 6 6 6 14]2[W02(S-mandalate )2] was used to catalyse oxidation of methyl phenyl sulfide by urea-H202 in the solvent CH2Cl2 + 2% EtOH to give the sulfoxide in 53% yield with 95% selectivity and 96%... 

Bearing these considerations in mind, Reddy and Verkade prepared a titanium alkoxide complex, 72, with good stability toward moisture for the selective oxidation of sulfides to sulfones and sulfoxides with hydrogen peroxide in recyclable ionic liquid solvents at room temperature [56]. They optimized reaction conditions and recovering procedure for thioanisole 71, and used their obtained results for oxidation of different aliphatic, aromatic and xmsaturated sulfides. Their results proved the chemoselectivity... 

Zinc sulfide (ZnS) has attracted an interest as an appropriate material to replace a CdS buffer layer in photovoltaic devices. ZnS in a cubic form exhibits a band gap of 3.54 eV at room temperature, while the hexagonal form has a band gap of 3.91 eV. Furthermore, it can be doped as either an n-type or p-type semiconductor. There is only one study on the electrodepostition of ZnS in ionic liquids. Dale et al. [24] reported that thin film of ZnS with a band gap of 3.6 eV can be deposited on FTO-coated glass in ChCl/urea ionic liquid containing ZnCl2 and... 

Murugesan S, Kearns P, Stevenson KJ (2012) Electrochemical deposition of germanium sulfide from room-temperature ionic liquids and subsequent Ag doping in an aqueous solution. Langmuir 28(13) 5513-5517. doi 10.1021Aa300551z... 

Manan NSA, Aldous L, Alias Y, Murray P, Yellowlees LJ, Lagunas MC, Hardacre C (2011) Electrochemistry of sulfur and poly sulfides in ionic liquids. J Phys Chem B 115 13873-13879... 

Ionic conduction can be observed in numerous systems liquids showing self-dissociation (e.g., water, hydrogen sulfide), solutions containing ions formed by dissociation of salts (true or real electrolytes, e.g., NaCl) or molecules (potential electrolytes, e.g., HCl) (these systems are frequently called electrolyte, obviously this convenient simplification is misleading), molten salts, ionic liquids, ionic crystals, etc. 

Other studies mention the use of solvents from the sulfonate family, including toluene, added into the electrolyte (2-10% volume), which decreases the dissolution and diffusion of poly sulfides through the electrolyte. Furthermore, this adjuvant helps improve the saturability of the electrolyte with the positive electrode. Finally, as it has low viscosity, toluene also improves the ionic conductivity of the electrolyte. A number of authors also make a case for the use of ionic liquids, stating that it is possible to decrease/limit the dissolution of the active material in the electrolyte by using this very particular family of solvents. 

H2O2 oxidation of various sulfides to sulfoxides. The sulfoxides were obtained in good to high yields and high selectivity without any detectable overoxidation to sulfone. More importantly, the flavin catalyst 26 in the ionic liquid was recycled up to seven times in the sulfoxidation of some representative sulfides without loss of activity or selectivity (Table 8.6) [50]. According to NMR, the zwitterionic form of flavin 26 predominates, which explains why 26 stays in the ionic liquid after the extraction of the product. 

Heterogeneous catalytic oxidation of sulfides in ionic liquids by anhydrous H2O2 or urea hydroperoxide with MCM-41 and related mesoporous catalysts containing Ti or Ti and Ge was studied by Hardacre and coworkers [51]. The Ti-based catalyst gave a quite selective sulfoxidation. Addition of Ge to Ti increased the rate of the oxidation but reduced the selectivity toward sulfoxide [51a]. 

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