Ionic second generation

Species dissolved in ionic liquids A number of systems have been investigated in both chloroaluminate and second generation ionic liquids... 

In 1992, the ionic liquid methodology received a substantial boost when Wilkes and Zaworotko described the synthesis of non-chloroaluminate, room temperature liquid melts (e. g. low melting tetrafluoroborate melts) which may be regarded as second generation ionic liquids [6]. Nowadays, tetrafluoroborate and (the slightly later published [7]) hexafluorophosphate ionic liquids are still widely used in ionic liquid research. However, their use in many technical applications will be clearly limited by their relatively high sensitivity towards hydrolysis. Of course, the tendency of their anions to hydrolyse is much less pronounced than for the chloroaluminate melts but it still clearly exists. Consequently, the technical application of tetrafluoroborate and hexafluorophosphate ionic liquids will be effectively restricted to those applications where water-free conditions can be realised at acceptable costs. 

Secondary wastewater treatment, 25 888 Second falling rate period, 23 66 Second-generation ionic liquids, 26 838, 847, 865... 

The so-called second generation ionic hquids were prepared from organic cations and AlCl anions [170]. Since AICI3 was present in these liquids, they were used as catalysts in Lewis acid catalyzed reactions. Also many of the third generation ionic liquids have been used as solvents for catalytic reactions [171-174], However, it is also known that third generation ionic liquids are capable of catalyzing reactions, either in substoichiometric amounts or as reaction medium. This will be discussed in this section. 

Ionic liquids in molecular solvents "Second-generation" or "modern" ILs are well defined cation-anion combinations that are liquid at room (or reaction) temperature. They normally consist of exactly one cation and one anion, and they are often air- and moisture-stable. Therefore, investigations on structure and speciation of this class of ILs have a different focus. In addition, the higher stability of these... 

Since late 2007, the Energy Biosciences Institute in Berkeley has been the center for cooperation between scientists from the University of California and the Agricultural Department of the University of Illinois for the production of fuels from so-called energy crops like switch grass. In this second-generation biofuel project that is financed over a 10-year period with 500 million by oil company BP, biomass is converted with the help of synthetic catalysts, for example, organometallic compounds, in a special solvent medium, better known as ionic liquids, into hydrocarbons with properties close to automotive fuels. 

Both the sulfone-tethered enyne 426 and diene 427 undergo RCM to give 5,6-dihydro-2//-thiopyran 1,1-dioxides when treated with a second generation Grubbs mthenium catalyst 425 tagged with an ionic liquid (Scheme 136) <2005JOM(690)3577>. 

Will, J. et al. (2000) Fabrication of thin electrolytes for second-generation solid oxide fuel cells. Solid State Ionics 131, 79-96. 

Ionic liquids have also been separated into first and second generation liquids [10] where first generation liquids are those based on eutectics and second generation have discrete anions [17]. Others have sought to further divide the first generation liquids into separate types depending on the nature of the Lewis or Bronsted acid that complexes [18]. While there is some dispute whether eutectics with Bransted acids constitute ionic liquids at all there are others who seek to widen the description of ionic liquids to include materials such as salt hydrates [19]. 

Within parts of the scientific community researching ionic liquids, often a notion of different "generations" of ionic liquids is expressed. The chloroaluminate ionic liquids can be viewed as the first generation of ILs. They show new and fascinating properties but their sensitivity towards water limits the possible uses for them. Tetrafluoroborates and Hexafluorophosphates can be considered ILs of the second generation. They have a lower or no sensitivity towards moisture and can be handled under air. Today, research scientists are working on the third and even fourth generation of ionic liquids. 

Recently, Cravotto and co-workers [111] demonstrated an efficient one-pot synthesis of second-generation ionic liquids, combining in one step the Menshutkin reaction and anion metathesis ... 

In order to understand these interactions, we consider systems containing second generation ionic liquids (i.e. without functionalisation on the cation substituent, no labile protons on either the cation or the anion, and bearing a hydrolytically stable anion). 

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