Ionic Liquids

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Green Chemistry Presentation
Ionic Liquid
Presented by :Xin Huang
Development
2003
Year
2001
1999
1997
1995
0
200
400
600
No of publications
800
1000
Outline
Definition
Advantage
Applications
Ionic liquid in synthesis
Examples
Conclusion
What are Ionic Liquids
Common Definition
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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 Cations
R1
R2
N
N
N
R
* [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
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Paul Walden
* The description of a low melting point salt 1914
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* The first room temperature ionic liquid 1951
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N-ethylpyridinium bromide- aluminium chloride melt
* The most stable and conductive salts 1982
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Ethyl ammonium nitrate
1,3-dialkylimidazolium salts
* The hydrophobic ionic liquids 1992
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1-ethyl-3-methylimidazolium tetrafluoroborate
Advantage
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Easy separation
Very low vapor pressure
Non-flammable substance
High thermally stable
High mechanically stable
Electrochemically stable
Low toxicity
Non-volatility
Application
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
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Catalytic
Friedel–Crafts
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Hydrogenetions
Alkoxycarbonylation
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Hydroformylations
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Heck reactions
Olefin dimerization
Diels-Alder
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Suzuki coupling
Stille Coupling
Oxidations
Diels-Alder reaction
Heck Reaction
Wittig reaction
Suzuki-Miyaura coupling reaction
Stille reaction
Friedel-Crafts reaction
Hydrogenation
Fluorination
12 principles of Green Chemistry
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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, JiChang Xiao *
Preparation of pyrrolidinium salts
Reaction
Flow chart
HNO3 65~68% 60℃, stirred overnight
+
N
H
H2O
washed with diethyl ether 50ml*3
r.t.
concentrated
yellow solid + CH 3OH
H
N
-O
+
filtration
filtrate
concentrated
stirred, 12h
H(CF2) 4O(CF2) 2SO3Na/MeOH
r.t.
N+
O
pale yellow liquid
AlCl3
50℃, stirred
extracted
toluene (3 ml*3)
upper-layer
concentrated
purified
TM.
(flash chromatography)
Green Aspects
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The yeild for preparing Ionic liquid is as high 99%. (Principle 2)
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Seperation of Ionic liquid is easy , just by filtration.
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Reaction condition is mild .(Principle 12)
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No byproducts in the preparation .(Principle 8)
Green Aspects
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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
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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
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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 .
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