01-03-2013, 10:43 AM
Ionic Liquid
[attachment=52256]
INTRODUCTION
Salts are solid having attraction force high,
Ions form when this attraction force will become low or negligible
History
1888: 1st IL synthesized by Gabriel:Ethanolammoniumnitrate m.p. 52-55 °C
1914: First RTIL: Ethylammoniumnitrate, m.p. 12 °C
1948
evelopment of IL with chloroaluminate ions by Hurley and Wier at the Rice Institute in Texas
1970‘s:IL based on 1,3-dialkylimidazolium or 1-alkylpyridinium halids or trihalogenaluminates
1980‘s:First publications in which IL were described as reaction media and catalysts for organic synthesis
1992:Wilkes and Zawarotko: weakly coordinating anions [PF6]-, [BF4]- [3]
later: triflate [CF3SO3]-, bistriflimide [(CF3SO2)2N]-
Defination
An ionic liquid (IL) is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below some arbitrary temperature, such as 100 °C (212 °F).
ILs are largely made of ions and short-lived ion pairs. These substances are variously called liquid electrolytes, ionic melts, ionic fluids, fused salts, liquid salts, or ionic glasses.
Characteristics
Ionic liquids are often moderate to poor conductors of electricity, non-ionizing (e.g. non-polar)
Highly viscous and frequently exhibit low vapour pressure.
Their other properties are diverse: many have low combustibility, excellent thermal stability, wide liquid regions, and favourable solvating properties for a range of polar and non-polar compounds.
Many classes of chemical reactions, such as Diels-Alder reactions and Friedel-Crafts reactions, can be performed using ionic liquids as solvents.
Recent work has shown that ionic liquids can serve as solvents for biocatalysis,
Why Ionic liquid is today’s hot topic?
The materials are unique (properties and variety)
– Tunability
– Negligible vapor pressure
– Good thermal stability
– Wide liquid range
– Electrolytic conductivity
The prospects for ILs applications are vast
– Possibility to establish environmentally benign chemical processing
20 million ton VOCs discharged into atmosphere per year
2/3 of all industrial emission and 1/3 of VOCs emission nationwide from traditional solvents
Industrial use :
Acid Scavenging-
The first major industrial IL application was the BASIL (Biphasic Acid Scavenging utilizing Ionic Liquids) process by BASF, in which 1-alkylimidazole scavenged the acid from an existing process. This then results in the formation of an IL which can easily be removed from the reaction mixture. This increased the space/time yield of the reaction by a factor of 80,000.
Cellulose processing-
This may allow for development of new processes and intensification of existing ones substituting existing cellulose solvents for ILs.
Summary
Because the properties and behaviour of the ionic liquid can be adjusted to suit an individual reaction type, they can truly be described as designer solvents. We have shown that, by choosing the correct ionic liquid, high product yields can be obtained, and a reduced amount of waste can be produced in a given reaction.
[attachment=52256]
INTRODUCTION
Salts are solid having attraction force high,
Ions form when this attraction force will become low or negligible
History
1888: 1st IL synthesized by Gabriel:Ethanolammoniumnitrate m.p. 52-55 °C
1914: First RTIL: Ethylammoniumnitrate, m.p. 12 °C
1948
evelopment of IL with chloroaluminate ions by Hurley and Wier at the Rice Institute in Texas1970‘s:IL based on 1,3-dialkylimidazolium or 1-alkylpyridinium halids or trihalogenaluminates
1980‘s:First publications in which IL were described as reaction media and catalysts for organic synthesis
1992:Wilkes and Zawarotko: weakly coordinating anions [PF6]-, [BF4]- [3]
later: triflate [CF3SO3]-, bistriflimide [(CF3SO2)2N]-
Defination
An ionic liquid (IL) is a salt in the liquid state. In some contexts, the term has been restricted to salts whose melting point is below some arbitrary temperature, such as 100 °C (212 °F).
ILs are largely made of ions and short-lived ion pairs. These substances are variously called liquid electrolytes, ionic melts, ionic fluids, fused salts, liquid salts, or ionic glasses.
Characteristics
Ionic liquids are often moderate to poor conductors of electricity, non-ionizing (e.g. non-polar)
Highly viscous and frequently exhibit low vapour pressure.
Their other properties are diverse: many have low combustibility, excellent thermal stability, wide liquid regions, and favourable solvating properties for a range of polar and non-polar compounds.
Many classes of chemical reactions, such as Diels-Alder reactions and Friedel-Crafts reactions, can be performed using ionic liquids as solvents.
Recent work has shown that ionic liquids can serve as solvents for biocatalysis,
Why Ionic liquid is today’s hot topic?
The materials are unique (properties and variety)
– Tunability
– Negligible vapor pressure
– Good thermal stability
– Wide liquid range
– Electrolytic conductivity
The prospects for ILs applications are vast
– Possibility to establish environmentally benign chemical processing
20 million ton VOCs discharged into atmosphere per year
2/3 of all industrial emission and 1/3 of VOCs emission nationwide from traditional solvents
Industrial use :
Acid Scavenging-
The first major industrial IL application was the BASIL (Biphasic Acid Scavenging utilizing Ionic Liquids) process by BASF, in which 1-alkylimidazole scavenged the acid from an existing process. This then results in the formation of an IL which can easily be removed from the reaction mixture. This increased the space/time yield of the reaction by a factor of 80,000.
Cellulose processing-
This may allow for development of new processes and intensification of existing ones substituting existing cellulose solvents for ILs.
Summary
Because the properties and behaviour of the ionic liquid can be adjusted to suit an individual reaction type, they can truly be described as designer solvents. We have shown that, by choosing the correct ionic liquid, high product yields can be obtained, and a reduced amount of waste can be produced in a given reaction.