https://www.chem.ccu.edu.tw/~joyce/referance/gump/IL/Chem.%20Rev.%201999,%2099,%202071.pdf

Room-Temperature Ionic Liquids. Solvents for Synthesis and Catalysis

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.

Structure and nanostructure in ionic liquids.

Ionic liquids in catalysis

Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as ‘g cellulose per mole of IL’ or ‘mol IL per mol hydroxyl in cellulose’ to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate ‘greenness’ of any process (142 references).

Ionic liquid processing of cellulose

Diels-Alder reactions in room-temperature ionic liquids

The role of hydrogen bonding in controlling the selectivity of Diels–Alder reactions in room-temperature ionic liquids

Ionic liquids provide a solvent environment quite unlike any other available at, or near room temperature. The challenge is to discover whether that environment can add significant advantage for synthesis. Initial investigations show that ionic liquids can be exploited in several ways. They can be used as an integral component of the reaction or catalyst system, or they may be used as an “innocent” solvent.

Ionic Liquids as Solvents for Organic Synthesis

Dynamic Supramolecular Chemistry: The Role of Hydrogen Bonding in Controlling the Selectivity of Diels-Alder Reactions in Room-Temperature Ionic Liquids

The use of ionic liquids as solvents for synthesis and catalysis is discussed. We focus on how the ionic liquids can interact (or not) to make changes in the observed reactivities.

Alick R. Sethi

Papers

Diels-Alder reactions in room-temperature ionic liquids

The role of hydrogen bonding in controlling the selectivity of Diels–Alder reactions in room-temperature ionic liquids

Ionic Liquids as Solvents for Organic Synthesis

Dynamic Supramolecular Chemistry: The Role of Hydrogen Bonding in Controlling the Selectivity of Diels-Alder Reactions in Room-Temperature Ionic Liquids

Synthesis and Catalysis in Room-Temperature Ionic Liquids