Ionic Liquid Presented by :Xin Huang Green Chemistry Presentation.
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Transcript of Ionic Liquid Presented by :Xin Huang Green Chemistry Presentation.
Outline
Definition Definition
ConclusionConclusion
Examples Examples
Ionic liquid in synthesisIonic liquid in synthesis
AdvantageAdvantage
ApplicationsApplications
Common Definition
Ionic Liquids (ILs) is the generic term for a class of materials, consisting entirely of ions and being liquid below 100°C.
If they are liquid at room temperature, we call them room temperature ionic liquids (RTILs).
Typical Cation and Anion
Typical IL CationsTypical IL Cations
N
R
N NR1 R2
* [PF6]- for moisture stable, water immiscible IL
* [BF4]- for moisture stable, but water miscible IL
* [AlCl4-] (or other Lewis acids) decomposes in water
Discovery and History * The description of a low melting point
salt - 1914 Ethyl ammonium nitrate
* The first room temperature ionic liquid -1951
N-ethylpyridinium bromide- aluminium chloride melt
* The most stable and conductive salts -1982
1,3-dialkylimidazolium salts * The hydrophobic ionic liquids -
1992 1-ethyl-3-methylimidazolium tetrafluoroborate
Paul Walden
Advantage Easy separation Very low vapor pressure Non-flammable substance High thermally stable High mechanically stable Electrochemically stable Low toxicity Non-volatility
Comparison of organic solvents with ionic liquids
Plechkova, N. V.; Seddon K. R. Chem. Soc. Rev. 2008, 37, 123–150
Ionic Liquids in Organic Synthesis
Catalytic
Hydrogenetions
Hydroformylations
Heck reactions
Suzuki coupling
Stille Coupling
Friedel–Crafts
Alkoxycarbonylation
Olefin dimerization
Diels-Alder
Oxidations
12 principles of Green Chemistry
1. Waste Prevention 2. Atom Economy 3. Less Hazardous Chemical Process 4. Designing Safer Chemicals 5. Safer Solvents and Auxiliaries 6. Energy Efficiency 7. Renewable Feedstocks 8. Reduce Derivatives 9. Catalysis 10. Design for Degradation 11. Real-time Analysis for Pollution Prevention 12. Safer Chemistry for Accident Prevention
Journal of Fluorine Chemistry
A novel pyrrolidinium ionic liquid with 1,1,2,2 tetrafluoro 2 (1,1,2,2-tetrafluoroethoxy)
ethanesulfonate anion as a recyclable reaction medium and efficient catalyst for Friedel–Crafts
alkylations of indoles with nitroalkenes
Jin-Hong Lin, Cheng-Pan Zhang, Zhi-Qiang Zhu, Qing-Yun Chen, Ji-Chang Xiao *
Flow chart
NH
+ H2OHNO3 65~68%
r.t.
60℃, stirred overnight washed with diethyl ether 50ml*3
concentratedyellow solid
TM.
+ CH3OHH(CF2)4O(CF2)2SO3Na/MeOH stirred, 12h
f iltration
r.t.
f iltrateconcentrated
pale yellow liquid
HN
N+
O
-O
+
50℃, stirred extracted
toluene (3 ml*3)upper-layer
concentrated purified
(flash chromatography)
AlCl3
Green Aspects The yeild for preparing Ionic liquid is as high 99%.
(Principle 2)
Seperation of Ionic liquid is easy , just by filtration.
Reaction condition is mild .(Principle 12)
No byproducts in the preparation .(Principle 8)
Green Aspects
The high concentration of highly acidic species that can be immobilized in ionic liquids and that leads to a highly reactive catalytic phase allowing for fast reactions under mild conditions. In fact, acidic ionic liquids catalyze all reactions that are conventionally catalyzed by AlCl3, but without suffering the disadvantage of the low solubility of AlCl3 in many solvents.
(Principle #3,5,9)
The liquid nature of the catalytic phase eliminates the heat and mass transfer problems frequently encountered with heterogeneous Friedel–Crafts-catalysts and make the reaction get high yield .(Principle 2)
The miscibility gap of most ionic liquids with alkylated aromatics allows for product isolation by simple decantation.(Principle #1,7)
Green Aspects Ionic liquid also act as solvent in this
reaction ,it prevents the waste of solvent.
(Principle 1)
Ionic liquid can be used directly for the next run after removing the solvent. Principle 7
Conclusion Ionic liquids ,as the new materials of multifunction , are
widely used in various of fields.
Environmently-friendly reaction process have vigorously been studied from the standpoint of green chemistry and based on the properities of easy separation , low toxicity , selective miscibility , ILS play an important role in organic synthesis as the green alternative solvent.
Withe the development of multifunctional ILS , we can expect IlS would apply in more fields .