Ionic liquids are salts that are liquid at low temperature (<100 degrees C) which represent a new class of solvents with nonmolecular, ionic character. Even though the first representative has been known since 1914, ionic liquids have only been investigated as solvents for transition metal catalysis in the past ten years. Publications to date show that replacing an organic solvent by an ionic liquid can lead to remarkable improvements in well-known processes. Ionic liquids form biphasic systems with many organic product mixtures. This gives rise to the possibility of a multiphase reaction procedure with easy isolation and recovery of homogeneous catalysts. In addition, ionic liquids have practically no vapor pressure which facilitates product separation by distillation. There are also indications that switching from a normal organic solvent to an ionic liquid can lead to novel and unusual chemical reactivity. This opens up a wide field for future investigations into this new class of solvents in catalytic applications.

Ionic Liquids-New "Solutions" for Transition Metal Catalysis.

Fast pyrolysis utilizes biomass to produce a product that is used both as an energy source and a feedstock for chemical production. Considerable efforts have been made to convert wood biomass to liquid fuels and chemicals since the oil crisis in mid-1970s. This review focuses on the recent developments in the wood pyrolysis and reports the characteristics of the resulting bio-oils, which are the main products of fast wood pyrolysis. Virtually any form of biomass can be considered for fast pyrolysis. Most work has been performed on wood, because of its consistency and comparability between tests. However, nearly 100 types of biomass have been tested, ranging from agricultural wastes such as straw, olive pits, and nut shells to energy crops such as miscanthus and sorghum. Forestry wastes such as bark and thinnings and other solid wastes, including sewage sludge and leather wastes, have also been studied. In this review, the main (although not exclusive) emphasis has been given to wood. The literature on woo...

Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review

In contrast to a recently expressed, and widely cited, view that “Ionic liquids are starting to leave academic labs and find their way into a wide variety of industrial applications”, we demonstrate in this critical review that there have been parallel and collaborative exchanges between academic research and industrial developments since the materials were first reported in 1914 (148 references)

Applications of ionic liquids in the chemical industry

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Ionic-liquid materials for the electrochemical challenges of the future.

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.

http://science.sciencemag.org/content/sci/302/5646/792.full.pdf

Ionic Liquids--Solvents of the Future?

We report here initial results that demonstrate that cellulose can be dissolved without activation or pretreatment in, and regenerated from, 1-butyl-3-methylimidazolium chloride and other hydrophilic ionic liquids. This may enable the application of ionic liquids as alternatives to environmentally undesirable solvents currently used for dissolution of this important bioresource.

/pdf/dissolution-of-cellose-with-ionic-liquids-2k5aeg52ii.pdf

Dissolution of Cellose with Ionic Liquids

Room temperature ionic liquids as novel media for ‘clean’ liquid–liquid extraction

Hydrophilic ionic liquids can be salted-out and concentrated from aqueous solution upon addition of kosmotropic salts forming aqueous biphasic systems as illustrated by the phase behavior of mixtures of 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and K3PO4.

Controlling the aqueous miscibility of ionic liquids: aqueous biphasic systems of water-miscible ionic liquids and water-structuring salts for recycle, metathesis, and separations.

Richard P. Swatloski

Papers

Dissolution of Cellose with Ionic Liquids

Room temperature ionic liquids as novel media for ‘clean’ liquid–liquid extraction

Controlling the aqueous miscibility of ionic liquids: aqueous biphasic systems of water-miscible ionic liquids and water-structuring salts for recycle, metathesis, and separations.

Ionic liquids are not always green: hydrolysis of 1-butyl-3-methylimidazolium hexafluorophosphate

Task-specific ionic liquids for the extraction of metal ions from aqueous solutions