An idiosyncratic family
The TAA Family
The properties of
tetra-alkylammonium-based ionic liquids
The TAA Family
José Nuno Canongia Lopes
Centro de Química Estrutural, CQE/IST/UTL, Lisbon, Portugal
Instituto de Tecnologia Química e Biológica, ITQB/UNL, Oeiras, Portugal
Luís Paulo N. Rebelo
Instituto de Tecnologia Química e Biológica, ITQB/UNL, Oeiras, Portugal
Acknowledgements:
Karina Shimizu and Carlos Bernardes (IST/UTL),
José Esperança, Isabel Marrrucho, Anabela Costa and Mário Soromenho (ITQB/UNL)
Finantial Support from FCT (PTDC program)
[email protected]
The TAA Family: Introductions
1
Siegmund Gabriel (1851-1924)
ethanolammonium nitrate (1888)
Paul Walden (1863-1957)
ethylammonium nitrate (1914)
Adolph Strecker (1822-1871)
cholinium chloride (1864, 1866)
gentleman with monocle
pyrrolidinium cations
child with soap bubble
cations from CTAB surfactants
photographer with tripod
trialkylmethylammonium cations
The TAA Family: flexibility
JPCB 2008, 1465-1472
2
The TAA Family: pyrrolidinia ILs versus CTABs and CCDABs
CnTAB
CnCmDAB
CnC1pyrr Br
CnCmpyrr Br
JCIS 2011, 606-616
3
The TAA Family: from CTAB cations to tripod ILs
4
The TAA Family: tripod ILs & LCILs ?
5
The TAA Family: tripod ILs & LCILs ?
5
[NTf2]–
[NTf2]–
?
[NTf2]–
JPCB 2010, 15635-15641
Pott et al, PCCP 2009, 5469-5475
The TAA Family: tripod ILs & other ILs
5
[NTf2]–
[C14mim][NTf2]
[P6 6 6 14][NTf2]
TheoChem 2010, 70-76
[NTf2]–
[NTf2]–
JPCB 2010, 15635-15641
The TAA Family: choline
6
Choline, a.k.a. cholinium chloride, is the salt combining the
N,N,N-trimethyl-hydroxyethyl-ammonium cation, [N1 1 1 2OH]+, with the chloride anion.
It is classified as an essential nutrient for humans.
Its not an IL (decomposes above 570 K before melting)
Cholinium bistriflamide = [N1 1 1 2OH][Ntf2]
Cn Cholinium bistriflamide = [N1 1 n 2OH][Ntf2]
The TAA Family: Cn cholinium cations
7
Pure Cn Cholinium bistriflamide series
g.cm-3
C1
1.3
290
C5
T/K
C1
370
ap
6.5
C5
5.9
290
C1
C2
ChemPhysChem 2012, 13, 1902 – 1909
T/K
370
C3
200
mPa.s
r
104.K-1
1.6
75
1
C4
Cn
5
C5
[N1 1 n 2OH][Ntf2]
The TAA Family: Cn cholinium cations
Cn Cholinium bistriflamide, [N1 1 n 2OH][Ntf2]: IL Structure
J Phys Chem B 2012, ASAP
8
The TAA Family: mixtures with molecular compounds
9
Cn Cholinium bistriflamide + water binary mixtures
C3
C4
C5
J Phys Chem B 2012, submitted
([N1 1 n 2OH][Ntf2] + H2O)
The TAA Family: mixtures with molecular compounds
10
Cn Cholinium bistriflamide + 1-octanol binary mixtures
J Phys Chem B 2012, submitted
([N1 1 n 2OH][Ntf2] + 1-C8H17OH)
The TAA Family: mixtures with molecular compounds
11
Cn Cholinium bistriflamide + 1-octanol + water ternary mixtures
([N1 1 1 2OH][Ntf2] + 1-C8H17OH + H2O)
([N1 1 5 2OH][Ntf2] + 1-C8H17OH + H2O)
J Phys Chem B 2012, ASAP
The TAA Family: mixtures with molecular compounds
12
Three Cn Cholinium bistriflamides + Six different ethers: the three ILs
[N1 1 2 2OH][Ntf2]
[N1 1 5 2OH][Ntf2]
[N1 1 8 2OH][Ntf2]
The TAA Family: mixtures with molecular compounds
13
Three Cn Cholinium bistriflamides + Six different ethers: the six ethers
Butyl methyl ether
Diethyl ether
sec-Butyl-methyl ether
tert-Butyl ethyl ether
tert-Butyl-methyl ether
tert-Amyl methyl ether
The TAA Family: mixtures with molecular compounds
14
C5 Cholinium bistriflamide + five different ethers
–
+
380
T/K
340
300
260
220
180
0.0
0.2
0.4
0.6
0.8
x IL
1.0
The TAA Family: mixtures with molecular compounds
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
360
340
320
300
280
260
240
220
200
0.0
0.5
1.0
15
The TAA Family: mixtures with molecular compounds
16
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
Higher solubilities and LCSTs:
1) C8 > C5 > C2 cholinium bistriflamide
2) Methyl ethers > ethyl ethers
(e.g.,
>
)
3) More compact alkyl chains better than long alkyl chains
( e.g.,
>
)
The TAA Family: mixtures with molecular compounds
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
Higher solubilities and LCSTs:
1) C8 > C5 > C2 cholinium bistriflamide
Larger non-polar domains in the IL where the ethers can dissolve
C2
C5
17
The TAA Family: mixtures with molecular compounds
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
360
340
320
300
280
260
240
220
200
0.0
0.5
1.0
18
The TAA Family: mixtures with molecular compounds
19
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
Higher solubilities and LCSTs:
2) Methyl ethers > ethyl ethers
(e.g.,
>>
)
Better H-bond-type interactions between the ether O atom and the cholinium OH group
6
g(r)
4
2
0
0
0.8
r / nm
1.6
LCSTs in ILs+Ethers
20
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
360
340
320
300
280
260
240
220
200
0.0
0.5
1.0
The TAA Family: mixtures with molecular compounds
21
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
Higher solubilities and LCSTs:
3) More compact alkyl chains better than long alkyl chains
( e.g.,
>
)
Smaller non-polar domains in C2 and C5 accommodate better more compact alkyl
residues.
C2
C5
The TAA Family: mixtures with molecular compounds
three (C2, C5, C8) Cholinium bistriflamides + five different ethers
360
340
320
300
280
260
240
220
200
0.0
0.5
1.0
22
The TAA Family: mixtures with molecular compounds
23
Final Comments
1) Imidazolia watch out! Time for some tetra-alkyl ammonia (TAAs). Alkyl chains can
grow on these too (even more so in tripod-like TAAs).
2) Pyrrolidinium is a cyclic TAA cation with two “hindered” legs. Nevertheless the
pseudorotation of the ring promotes some internal flexibility.
3) Cholinium is a functionalized TAA cation. The hydroxy group is capable of H-bondlike interactions with different solvents (water, alcohols, ethers). The outcome can
be quite differentiated and dramatic.
4) No more boring immiscibility walls in mixtures containing bistriflamide-based ILs.
UCSTs and LCSTs are ubiquitous in Cholinium-based ILs and can be moved at will.
Thank You!
[email protected]