The slide contains all about protic ionic liquid also commonly known as designer solvent

1. Protic ILs
ILs can be divided into two broad categories, viz.,
aprotic ionic liquids (AILs) and protic ionic liquids
(PILs)
PILs are formed through the transfer of a proton from
a brӧnsted acid to a brӧnsted base
Commonly used cations are 1°, 2°, 3° ammonium,
imidazolium, pyrrolidonium, caprolactum, glycine,
proline etc & anions are carboxylate, nitrate, TFSI,
BETI, Tfa, SCN- , HSO4
-etc

2. General properties
The choice of the cation and anion determines the
physicochemical properties.
A key feature of PILs is that they are capable of
hydrogen bonding, including proton acceptance and
proton donation
The majority PILs have nonnegligible vapor pressures,
but their beneficial properties for the applications out
weigh this potentially negative property[1]
[1]Greaves,T.L; Weerawardena,A; Fong,C;Krodkiewska,I; Drummond,J, J. Phys. Chem. B 2006, 110, 22479-
22487

3. Preparation
Acids are added slowly to bases in a stoichiometric
ratio with vigorous stirring
CH3CH2NH2 + HNO3 CH3CH2NH3+ NO3-
As neutralization reaction is exothermic a low
Temperature should be maintained to prevent
evaporation of base
short chain carboxylic acids (formic, acetic) are prone
to degradation with the formation of amide as
byproducts

4. Physico chemical properties
Glass Transition:
The glass transition is indicative of the cohesive
energy
within the salt, it is decreased by repulsive Pauli
forces from the overlap of closed e¯ shells and
increased through the attractive Coulomb and
vanderWaals interactions[2]
It is measured by DSC
[2] Xu, W.; Cooper, E. I.; Angell, C. A. J. Phys. Chem. B 2003, 107,6170.

5. Melting Point & Thermal Stability
For low mp PILs, sufficient steric hindrance needed to
disrupt the packing efficiency and minimize the
hydrogen bonding.
PILs with a large proton-transfer energy will
decompose before reaching their boiling point[3]. The
decomposition temperatures(Td) of the PILs lie mostly
between 120⁰ and 360 °C.
Td is measured by DSC
[3]Belieres, J.-P.; Angell, C. A. J. Phys. Chem. B 2007, 111, 4926

6. Density
The density decreases slowly as the alkyl chain
length increases for alkyl ammonium cations,
alkylimidazolium cations, or alkylcarboxylate anions
The substitution of a OH¯ group onto the alkyl chain
of either of the ion increased the density, probably
because of increased H- bonding decreases the ion-
ion separations[4]
It is measured by density meter(Anton Paar)
[4]Greaves, T. L.; Weerawardena, A.; Fong, C.; Krodkiewska, I.;Drummond, C. J. J. Phys. Chem. B 2006, 110,
22479

7. Refractive Index & Surface tension
The refractive index (nD ) of a material is a measure of
polarity
The surface tension(σ) will be decreased when the
ions have a higher packing efficiency
Substituting a OH¯group onto either of the ion
increased the σ & nD
increasing the alkyl chain decreases σ while
increases nD
[5]
σ is measured by du nouy method among others
[5]Greaves, T. L.; Weerawardena, A.; Fong, C.; Krodkiewska, I.;Drummond, C. J. J. Phys. Chem. B 2006, 110,
22479.

8. Ionic conductivity
The ionic conductivity is governed by the mobility of
the ions. It depends on the viscosity and the number
of charge carriers
It also depend on the molecular weight, density, and
ion sizes
Any ion association will cause a decrease in the ionic
conductivity through decreasing the number of
available diffusible ions[6]
It is measured by conductivity meter(solartron)
[6]Tokuda, H.; Hayamizu, K.; Ishii, K.; Susan, M. A. B. H.; Watanabe,M. J. Phys. Chem. B 2004, 108, 16593

9. Viscosity
The viscosity is dependent on the ion-ion
interactions, such as vander Waals interactions and
hydrogen bonding
The anion structure has a far greater effect on the
viscosity than similar changes to the cation[7]
It is measured with a Carri-Med CSL2 100 Rheometer
[7]Chemical Reviews, 2008, Vol. 108, No. 1

10. Application of PILs
PILs are used in organic synthesis as a solvent
as well as catalyst
It is used as nonaqueous electrolyte in polymer
membrane fuel cells
It also act as lubricants
It has many industrial & biological application
It can also be used as a stationary phase in GC

11. Our plan: what to do
Our intend is to prepare ammonium based PIL
because
It is less toxic
It can be used as a CO2 scavenger in industrial process
So our proposed base will be N,N-diethyl hydroxyl
amine(BP:124-126)
The hydroxyl group present will influence for
hydrogen bonding

12. High thermal decomposition temperature
Among acids the inorganic anions are more likely to
be solid at room temperature[8] & also they are very
much aggressive
Formic & ethanoic acids are also not suitable for
distillation because of low thermal stability
So we proposed a strong carboxylic acid CF3COOH
which enhances the proton transfer process
[8] Tamar L. Greaves etal, J. Phys. Chem. B 2006, 110, 22479-22487

13. Detailed process
Water content should be removed from starting
material with the help of molecular sieve(4A°)
Equimolar acid will be taken & then added to the
base drop wise to prevent the formation of amide
The system should be kept in ice bath during acid
addition & then with constant stirring(at room temp.)
near about 24 hrs
The product is then characterized by 1H NMR(δ≈3) &
FT-IR(broad peak:3500-2400 cm-1)

14. Detailed process
The PILs obtained will be dried under high vacuum
(.1pa) for over night to remove excess water content
The water content will then be determined by karl-
fischer titrator(DL39-mettler toledo)
The various thermo physical properties like Tg, Tm, Tb,
ρ, η, k, cp, nD etc can be measured at various ranges
of temperature by using the above mentioned
technique

15. Binary mixture
The binary mixture will be made with water, aceto
nitrile & methanol with different mole fraction of PILs
Apart from several usefulness of binary mixture it
lowers the energy requirements for CO2 absorption
Molar excess volume, deviation in viscosity, heat
capacity etc will be calculated
The values are then fitted to Redlich-Kister[9]
polynomial equation to determine the binary
coefficients to know the molecular interaction
[9] Kiki A. Kurnia · M.I. Abdul Mutalib · T. Murugesan ·B. Ariwahjoedi,J Solution Chem, 2011, 40, 818–
831