10.1021/acs.jced.9b00800.s001
Marisa
A.A. Rocha
Marisa
A.A.
Rocha
Daniela Kerlé
Daniela
Kerlé
Johannes Kiefer
Johannes
Kiefer
Wolffram Schröer
Wolffram
Schröer
Bernd Rathke
Bernd
Rathke
Liquid–Liquid Phase Behavior of Solutions of
1,3-Diethylimidazolium Bis((trifluoromethyl)sulfonyl)amide in <i>n</i>‑Alkyl Alcohols
American Chemical Society
2020
dynamic
cationic side chains
mixture
phase behavior
solution
propan -1-ol butan -1-ol hexan -1-ol
MD
miscibility
UCST
cloud point method
C 2 C 2 imNTf 2
C x mimNTf 2 IL family
C 3 mimNTf 2
octan -1-ol
isomeric IL C 3 mimNTf 2
alkyl alcohols
phase diagrams
C x mimNTf 2 family
2020-01-15 18:36:45
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Liquid_Liquid_Phase_Behavior_of_Solutions_of_1_3-Diethylimidazolium_Bis_trifluoromethyl_sulfonyl_amide_in_i_n_i_Alkyl_Alcohols/11620761
The
cloud point method is applied for the characterization of the
limited miscibility of ionic liquid (IL) solutions. Here, we report
the phase behavior of binary mixtures of the ionic liquid 1,3-diethylimidazolium
bis((trifluoromethyl)sulfonyl)amide (C<sub>2</sub>C<sub>2</sub>imNTf<sub>2</sub>) with <i>n</i>-alkyl alcohols (propan-1-ol, butan-1-ol,
hexan-1-ol, and octan-1-ol) in a temperature range (<i>T</i>) of 258–386 K. The two components exhibit partial miscibility
with upper critical solution temperatures (UCSTs) between 284 and
386 K. In concordance with previous studies, a detailed shape analysis
presuming Ising behavior of the phase diagrams reveals the critical
points and further properties of the phase diagrams. The results are
compared with the isomeric IL C<sub>3</sub>mimNTf<sub>2</sub> from
the C<sub><i>x</i></sub>mimNTf<sub>2</sub> family. Unraveling
the influence of the molecular structure of the cation on the phase
behavior is the main focus of the present investigation. The comparison
between the two isomeric ILs, C<sub>2</sub>C<sub>2</sub>imNTf<sub>2</sub> and C<sub>3</sub>mimNTf<sub>2</sub>, shows an increase of
the UCST for the symmetric cation. A clear trend of lifting the UCST
toward higher values is observed when dealing with longer chained <i>n</i>-alkyl alcohols. This behavior is put into context with
a more generalized view on the phase behavior of the C<sub><i>x</i></sub>mimNTf<sub>2</sub> IL family. An effective number
of carbon atoms of the cationic side chains is determined for the
mixtures with different alcohols. For alcohols with chains ≤6,
the effective carbon number is constant and about 3.79, while for
octan-1-ol, a slightly lower value of 3.55 was observed. That gives
evidence of a change of the molecular ordering of the system. The
experimental study is supported by molecular dynamics (MD) simulations
to attain a better understanding at the molecular level. The local
dynamics and structures are analyzed in detail and reveal the effect
of the symmetry on different physicochemical properties.