Thermo Physical Properties of Lewis Acidic Ionic Liquids
[Bu3NBn] Cl-2(MClm), (MClm= AlCl3, FeCl3, CuCl2,SnCl4, ZnCl2)
binary mixtures with DMSO at Temperatures from
(298.15 to 363.15) K
Zeinab Heidari Pebdani1*, Abdol Reza Hajipour1 and Yosofe Ghayeba1
1Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156, IR Iran
Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan 84156, IR Iran; E-mail: @
Received: April 04, 2019; Accepted: April 26, 2019; Published: May 02, 2019
Citation: Zeinab Heidari P, Abdol Reza H, Yosofe G (2019) Thermo Physical Properties of Lewis Acidic Ionic Liquids [Bu 3NBn] Cl-2(MClm), (MClm= AlCl3, FeCl3, CuCl2,SnCl4, ZnCl2) binary mixtures with DMSO at Temperatures from (298.15 to 363.15) K. Int J Anal
Medicinal Chem. 2(1): 1-12.
In this article, we were investigated as a function of temperature,
densities (𝜌), dynamic viscosities (η), surface tension (σ), ionic
conductivity (κ), refractive indices (nD),and thermal conductivity
(λ) for the binary systems of the DMSO with ionic liquids (ILs) over
the whole composition range at temperature from 298.15 to 363.15
Kelvin under atmospheric pressure. The ILsinvestigated in the
present study included [Bu3NBn]Cl-2(MClm), (MClm= AlCl3,CuCl2,
FeCl3, SnCl4,ZnCl2) that synthesis for the first one in our laboratory.
At first, we investigated Biodegradation and Toxicity of the ILs as
served for Green Solvent. Then, the influence of temperature on the
thermo physical properties on the new series of room temperature
ionic liquids (RTILs), have been prepared and characterized using
TLC, CHNS, FT-IR and Mass Spectroscopy.Thermogravimetric analysis
(TGA) confirmed that the heat stability of ILs in the temperature
range of 400-800°C.A common and effective way to evaluate the
Acidity of Lewis acids was the Hammett method (Ho) that we used
them for RTILs. Also, Densities, dynamic viscosity, surface tension,
ionic conductivity, refractive indices, thermal conductivity deviations,
and dynamic viscosity deviations in for the binary systems with Di-
Methyl Sulfoxide (DMSO) were fitted to a Vogel-Fulcher-Tammann
(VFT) equation. In the end, we offer some useful applications and
future perspectives for these new ILs. In comparison with the other
ILs in that how do the thermo physical properties and the most
advantages and the superiority of these systems when compared to
the ones reported in the literature being easily produced and used in
the various temperatures.
Abbreviations: (LAILs) Lewis Acidic Ionic Liquids; (RTILs)
Room Temperature Ionic Liquids; (VOC) Volatile Organic Compounds;
(DMSO) Di-Methyl Sulfoxide.
Large attention is being strained towards Ionic Liquids (ILs)
as alternatives for usual molecular solvents used in organic
synthesis and catalytic reactions . They complement the family
of a"green solvents" counting water and supercritical fluids. In
order to check the biocompatibility of ILs, toxicity, eco-toxicity,
and biodegradation studies have to be carried out. ILs is usually
referred to as a "Green" alternatives to Volatile Organic Compounds
(VOCs). Instead of the "Green" marker, ILs can be characterized in
the arrangement of "Traffic Signal Lights as debated at the BATIL
(Biodegradation And Toxicity of Ionic Liquids) conference in
DECHEMA, Frankfurt, 2009. Biodegradation is one technique of
investigation to define and calculate how Ionic Liquids interaction
with the environment. Among these, room temperature ionic
liquids are definite as materials containing only ionic species
and having a melting point lower than 298 K. They display
many interesting properties such as slight vapour pressure, low
melting point, and large liquid range, only one of its kind salvation
talents and generally, the flexibility of their physicochemical
properties makes them really attractive. Most of the ILs studied
is based on [Bu3NBn] Cl-2(AlCl3), [Bu3NBn] Cl-2(CuCl2), [Bu3NBn]
Cl-2(FeCl3), [Bu3NBn] Cl-2(SnCl4) and [Bu3NBn] Cl-2(ZnCl2).
They have been recently proposed as solvents in chemical
reactions . multiphase bioprocess operations  and liquidliquid
separations  electrolytes for batteries and fuel cells
 stationary phases in gas chromatography mobile phase
additives in liquid chromatography and electrolyte additive
sin capillary electrophoresis (CE) .However, the awareness of
their physicochemical properties, which has been revealed to be
directly related to their purity level, for instance, the temperature
dependence of density, dynamic viscosity, conductivity, surface
tension, refractive index, and thermal conductivity.
Among the known ionic liquids, those series having
asymmetric quaternary ammonium cations are assumed to be
one of the most promising for battery electrolyte use because
they exhibit a wider electrochemical window, especially along
a cathodic direction, and than imidazolium cation-based ionic
liquids . However, quaternary ammonium-based ionic liquids
have the drawback of low ionic conductivity at 10-3 S cm-1 or
lower. Indeed, salts based on small quaternary ammonium
cations are basically solid around room temperature.11 In
contrast, an increase in cation size decreases cation mobility. The
mixing of cations is expected to lower the melting point of the salt
as reported by Sun ET al .
In spite of the interesting feature and practical importance
of Isothere are limited literature reports on the accurate
measurements of many of their fundamental physical and
chemical properties at various temperatures . Thus, in this
paper we wish to report the results of our studies on the physical,
electrochemical, thermodynamic and transport properties
of [Bu3NBn] Cl-2(AlCl3), [Bu3NBn] Cl-2(CuCl2), [Bu3NBn] Cl-
2(FeCl3) and [Bu3NBn] Cl-2(SnCl4), [Bu3NBn] Cl-2(ZnCl2).
Molecular structures of the five ILs are shown in the scheme. 1.
The properties physical of these five ILs, accurately measured at
atmospheric pressure and several temperatures include density,
viscosity, thermal stability, surface tension, refractive index,
conductivity, and thermal conductivity. The measured densities
as a function of the temperature from 298.15 to 363.15K, Also
we measured the Hammett parameter (Ho) that a common and
effective way to evaluate the acidity of Lewis acids we used them
for RTILs .
Preparation of ionic liquids
Materials: Chemicals of analytical grade were used for the
synthesis of the ILs. Tributylamine and DMSO were purchased
from the Sigma-Aldrich. (>99 % of purity), salts such as AlCl3,
CuCl2, FeCl3, SnCl4, ZnCl2, were purchased from Merck. The purity
of the ILs was further confirmed by FT-IR and Mass- spectroscopy
and elemental analysis. The RTILs were prepared from the
corresponding chlorides according to the procedures reported in
Synthesis of ILs: [Bu3NBn] Cl-2(AlCl3), [Bu3NBn] Cl-2(CuCl2),
[Bu3NBn] Cl-2(FeCl3), [Bu3NBn] Cl-2(SnCl4) and [Bu3NBn] Cl-
2(ZnCl2). Initially, tri-butyl Ammine Chloride and benzene
chloride was added in 1:1 to a round-bottom flask, Acetonitrile
were added and stirred thoroughly, and then anhydrous MClm
was added in 1:2 molar ratio to an oil path under the protection
of dry nitrogen in stages forming a liquid. The mixture was stirred
at room temperature for 30 min and then was heated to 800C. The
Chloro metallic ionic liquid was required to be kept in desiccators
because it easily reacts with moisture . Yield reaction 68%,
Scheme 1. Scheme 1
Scheme 1: Two steps preparation of ionic liquids
[Bu3NBn]Cl-2(AlCl3), FT-IR (NaCl): ν= 3325-3294, 2962-
2534, 1638-1380, 843-610, cm-1.Mass Spectroscopy (T=230 °C,
EI=70 eV): m/z=591, 552, 236, 185, 142, 100, 91, 57.
[Bu3NBn]Cl-2(CuCl2) FT-IR (NaCl): ν = 3036-3388, 2962-
2874, 2309-2359, 1378-1478, cm-1. Mass Spectroscopy (T=230
°C, EI=70 eV): m/z=753, 677, 616, 571, 466, 447, 428, 409, 396,
360, 351, 332, 309, 285, 188, 126, 84, 57.
[Bu3NBn]Cl-2(FeCl3). FT-IR (NaCl): ν =3782-3384, 2967-
2874, 1998-1825, 1477-1370, 878-702, cm-1. Mass Spectroscopy
(T=230 °C, EI=70 eV): m/z=474, 459, 369, 313, 285, 239, 210,
185, 176, 142, 91, 58.
[Bu3NBn]Cl-2(SnCl2). FT-IR (NaCl): ν =3526-3420, 2965-
2876, 2380-2309, 1679-1375, 846-701, cm-1. Mass Spectroscopy
(T=230 °C, EI=70 eV): m/z=690, 573, 260, 225, 155, 142, 120,
[Bu3NBn]Cl-2(ZnCl2). FT-IR (NaCl): ν =3092-3037, 2964-2742,
1969-1624, 1497-1348, 1031, 865-701, cm-1. Mass Spectroscopy
(T=230 °C, EI=70 eV): m/z=654, 626, 598, 535, 507, 190, 176, 142,
100, 91, 57.
Results and DiscussionTop
Toxicity and Eco (toxicity) of Ionic Liquids
Over the last decade, although a single toxicological test
yields valuable, regardless of restricted information, plenty
of publications have established a wide variety of a biological
test systems for toxicity testing of ionic liquids , . This
contains fungi, bacteria, algae, enzymes, rat cell line, fish, and so
Stock and colleagues highlighted that the consequence of
ionic liquids on acetyl cholinesterase . Enzymes are a vital
fragment of the human nervous system. Acetyl cholinesterase
is recognized to catalyze the hydrolysis of the neurotransmitter
acetylcholine, to acetate and choline. Inhibition of acetyl
cholinesterase results in muscular paralysis and other medically
significant nervous problems. A array of regularly used [Bu3NBn]
Cl-2(AlCl3), [Bu3NBn]Cl-2(CuCl2), [Bu3NBn]Cl-2(FeCl3), [Bu3NBn]
Cl-2(SnCl4) and [Bu3NBn]Cl-2(ZnCl2)ionic liquids were tested
in this analyse. [Bu3NBn]Cl-2(SnCl4) ionic liquid presented high
toxicity to acetyl cholinesterase at very low absorptions, while
[Bu3NBn] Cl-2(FeCl3) ionic liquid was non-toxic within the test
limits. This testing revealed that toxicity of these ionic liquids
lies in the cationic part and tri-butyl Ammine Benzen on the side
chain and not in the anionic part.
Another significant result of this assessment was that
growing the length of alkyl side chains rises the toxicity. This can
be clarified as long alkyl chain increases lipophilic nature of the
ionic liquids, which can then simply combine within the biological
membrane of nerve cell synapses . Comparable trends
between the toxicity and length of alkyl chain on luminescence
inhibition of Vibrio fischeri and promyelocytic leukaemia rat
cell line IPC-81 were reported by Ranke and co-workers .
Leukemia rat cell line IPC-81 was also used to detect the cytotoxic
effect of commercially accessible anions . The major anion
effect was found under the test system as following respectively.
[Bu3NBn] [Sn2Cl9]˃ [Bu3NBn][Zn2Cl5].
Bernot and associates confirmed that severe toxicity of certain
1-butyl-3-methyl imidazolium ionic liquids on Daphnia Magna
was mostly due to the cationic part . Daphnia Magna has
been widely used for ecotoxicological assessment of chemicals in
invertebrates. Ionic liquids were found to impact of the duplicate
of Daphnia Magna. [Bu3NBn][Zn2Cl5] was found to be the most
toxic in the test system (LC50: 3.05 mg/L). This study revealed
that the toxicity of ionic liquids was influenced by the cation
component, which was established by high LC50 values for sodium
salts of analogous anions. Yu and co-workers testified the toxicity
study of tributyl-Ammine-Benzencholoridionic liquid towards
the antioxidant defense system of Daphnia Magna . Swelling
the length of alkyl side chain with a difference of metal was found
again to surge toxicity. Toxicity of ionic liquids, in this case, was
owed to oxidative strain in Daphnia Magna, which was evaluated
by measuring the activity of antioxidant defense enzymes, levels
of the antioxidant [Bu3NBn] and metal i.e. per oxidation byproduct
of lipid. [Bu3NBn][Sn2Cl9] presented very high toxicity
with an LC50 of 0.03 mg/L less than 48 h incubation times.
In work to evaluate the eco (toxicity) of ionic liquids, Yun
and associates informed evaluate of freshwater microalgae
Selenastrum capricornutum . Thechloride salts of commonly
used [Bu3NBn] [Cu2Cl5]˃ [Bu3NBn][Fe2Cl7]˃ [Bu3NBn][Al2Cl7]˃
[Bu3NBn][Sn2Cl9]˃[Bu3NBn][Zn2Cl5] ILs were tested against
the S. capricornutum and compared with traditional watermiscible
organic solvents such as methanol, 2-propanol, and
dimethylformamide. Increase in the toxicity of imidazolium
cations was observed with an increase in incubation time, whereas
the opposite trend was found in the case of tetrabutylammonium
ILs. The growth inhibition of S. capricornutum was higher in
ionic liquids than organic solvents. A similar test system was
applied to investigate the toxicological effect of anions .
Toxicity of various anions incorporated with tributyl-Ammine-
Benzencholorid cation was compared with their respective
sodium and potassium salts. The anions were found to inhibit the
growth of freshwater algae S. capricornutum. The clear trend in
algae toxicity was observed as choloride (Cl-). Toxicity studies
(in fish, aquatic plants/invertebrates) on anionic surfactants
have shown that toxicity is dependent on a number of factors
such as alkyl chain length, solubility, and stability in water .
As the length of alkyl chain increases, toxicity increases until
certain limits. Further increase in chain length can decrease the
hydrophilic nature of these materials, reducing the bioavailability
of compound which results in a general decrease in the toxicity
In order for how do the thermo physical properties compare
with the new design ILs of these systems when compared to the
ones reported in the literature, reference for data demonstration
of toxicity of ionic liquids and regularly used organic solvents
Benzene- Dichlorom cthane- Carbon Tetrachloride- Hexane>
Cyclohexane- Tleptane- Ethylene Glycol- Toluene> Water- Acetone-
[OMIM][Cl]- [FMIM][NO3]- [EMIM][Lactate] [HMIM][Sacch]>
[bmpy][Cl]-[BMIM] [N(CN)2]- [EMIM][OctOSO3]-[BMIM][OAc]>
[EMIM][Cl]- [BMIM][EtOSO3]- [bmpy][(MeO)2PO3]- [EMIM]
Biodegradation of Ionic Liquids
Biodegradation is an essential parameter to investigate in
ILs, supporting the design of safer analogs where requisite,
decreasing environmentally persistent molecules in ecosystems.
Biodegradation a standardized tests the following section
delivers an overview of the biodegradation tests which are of
attention and accessible to ILs scientists. The research zone
of biodegradation is regarded as into the following terms:(І)
Primary biodegradation a the defeat of a precisephysicalmoiety,
example hydrolysis of an ester bond(И) Naturally biodegradable
a if a composite biodegrades B20% then the likelihood of
supplementary degradation is implicit(Ш) Readily biodegradable
a biodegrades a explicit % insidea specified timeframe(ІѴ)
Ultimately biodegradable a comprehensive collapse of a
composite(Ѵ) Mineralisation a decomposition of a complex into
fragments accessible to plants .
Because of the bigger size of the oxygen tank in the
circumstance of the ISO 10708 bottle equalled to the technique
defined by the OECD 301D, Table 1, a higher test material
absorptions can be used in the ISO 10708 test as the total of
oxygen inthe bottle was fewer of a limiting issue. Table 1
The biodegradation in seawater test OECD Table 1, differsfrom
the standard31experimentsin that the only microorganisms
existent were those set up indeed in the seawater test means.
The container was not charged with further inocula, while it was
complemented with nutrients. This test was not projected to
characterizea marine situation but rather evaluate biodegradation
in seawater means. Table 2
Table 1: OECD testing guidelines .
Pass level after 10 days
Biodegradability in seawater (TG 306)
>50% DOC removal
Shake flask and closed bottle variants
Table 2: OECD testing guidelines
Pass level after 5 days
Dissolved Organic Carbon (DOC)
CO2 Evolution Test (TG301B)
Manometric respirometry test (TG 301F)
Soil, sediment, and water
Owing to the natural complications of consuming a solid
standard for biodegradation and the use of Radiolabeled atoms,
there are a number of factors recommended by the OECD that
can be used to display the fate of chemical complexes in soil or
sedimentary environment. Major direction or pseudo-first command rate constant for
Degradation half-life (DT50)
The maximum exact growth rate .
One other arranged test for inherent biodegradation of
chemical compounds in the soil exists for ILs is in the OECD TG,
Biodegradation in soil
Biodegradation of imidazolium-based [Bu3NBn][Cu2Cl5]˃
[Zn2Cl5] ILs in soil were scrutinized for their biodegradability.
In this test, a passspot is not given and biodegradation is only
detected. Below the test circumstances, the test composite is
mixed with soil and sited in a great beaker vessel with CO growth
commonly dignified. Soil can be a species-rich blend but it is
predictable that the action will be less than a stimulated sludge
so the test is run over a 5 days period. In this particular study,
it was found that the linear alkyl [Bu3NBn][Fe2Cl7]example
undertook degradation of 35.1 ± 5.6% with the N(CN)derivative
being less biodegradable than other halides, producing14.0 ±
Determination of water content
Before their use, the ionic liquids samples were dried and
degassed under vacuum (10-3bar)at 85 °C during 3 h. After this
treatment, the mass fraction of water determined by coulometric
KarlaFischer titration using a Metrohm 756 KFCoulometer with
a Hydranala® Coulomat AG reagent.Defined water content (50 ±
10) 10-3w/w that was revealed very low levels of water.
Density was measured in a 25 ml pyknometer. In general,
density precisions are ±0.0005 g cm-3
.The temperature was
maintained using a thermostatic bath with a precision of ±0.01
K. All density measurements were repeated at least three times.
Densities of the ILs as a function of temperature are shown in
Fig. 1. As expected, densities decrease linearly with increasing
temperature and can be well correlated by the linear regression
The temperature-dependent densities (𝜌), refractive indices
(nD), surface tension (σ) and thermal conductivity (Κ) values
were fitted by the method of least squares using the following
equations (1) .
Where fitting parameter B and A are related to the coefficient
of volume expansion (gcm-3
) and extrapolated density at 0K
), respectively and T is the temperature (K). The adjustable
parameters of Eq. (2) for the density of these ILs are summarized
in Table 1.
Figure 1: Temperature dependence of density data for the ILs
In our viscosity measurements, ILs showed no deviation from
Newtonian behaviour in the investigated temperature range.
Kinematic viscosities were obtained using an LVDV-IPRIME
model viscometer made of Brookfield Co and capillary tube deep
in athermostated bath with a precision of ±0.01 K. The dynamic
viscosities were calculated from the densities with a precision
equal to 0.03 mPas. All measurements were repeated two
times. Sample viscosities were first determined as a function of
the temperature during a heating cycle from (298.15 to363.15)
K. Data on viscosity for the ILs at temperatures ranging from
(298.15 to363.15) K. are shown in Fig 2.
The temperature dependency of the dynamic viscosity values
fit well to the Vogela Tammann aFulcher (VTF) equation (2) .
Figure 2: Dynamic viscosity (η) as a function of temperature for ILs
Where T is the absolute temperature??, Band T? is adjustable
parameters. The?? (cP), B , and T?(K) parameters are given in
Table 2.Commonly used an equation to correlate the variation of
viscosity with temperature is the Arrhenius-like law Eq (3) .
Viscosity at initial temperature?? and the activation
energy(Ea) are characteristics parameters generally adjusted
from experimental data. Table 3 lists the parameters for both
equations with the standard relative deviation(S. D.) Eq (4):
Where zexp and zcal are the values of the experimental and
calculated property, n is the number of experimental data of
parameters. Table 4
AnAbbe Refractometry Model ATAGO-T3 programmable
digital with a measuring accuracy of(4 10-5) was used to measure
the refractive index ofvarious ILs in a temperature range of
(298.15 to 363.15) K. Thetemperature was controlled with an
accuracy of (0.05) K. The apparatus was calibrated and checked
before each series of measurements using pure organic solvents
(ethanol) with known refractive indices.35Refractive Indicescan
is well fitted by Eq (1). Table 5 Figure 3
Figure 3 shows the temperature dependence of the refractive
index for the studied ILs have refractive indices >1.4. As can be
seen from Fig. 3, for all three ILs, the refractive index decreases
linearly with increasing temperature.
Figure 3: Refractive Index (nD) as a function of temperature for ILs
We used Stalagmometer dope of falling for estimated surface
tension ILs. The surface tension of the ILs has been measured as
a function of temperature. The experimental data decrease with
increase in temperature in Fig 4. These values were compared
with those obtained with [Bu3NBn][Fe2Cl7] has high surface
tension than Lewis ILs. Based on these data, it appears that the
surface tension lowly decreases with increases temperature. The
relationship between surface tension and temperature can be
fitting by the Eq (1). Table 6
The present synthesized ionic liquids show a weak
temperature dependency on the surface tension in Fig 4.
Figure 4: Surface tension (s) as a function of temperature for ILs
The thermal conductivity was measured by using a KD2
thermal property meter (decagon, Canada), which is basedon the
transient hot-wire method. The KD2 meter has a probe with 60
mm length and 0.9 mm diameter, which integrates into its interior
a heating element and a thermo-resistor, and is connected to a
microprocessor for controlling and conducting the measurements.
The KD2 meter was calibrated by using distilled water and
standard ethylene glycol before any set of measurements. In
order to study the effect of temperature, a thermostat bath was
used, which was able to keep the temperature gularity within
the range of ±0.1 K. At least five measurements were taken for
each temperature to make sure the uncertainty of measurements
The relationship between thermal conductivity (?) and
temperature of can be fitting by the Eq (1) and fitting parameters
listed in table 5. Table 7
Fig5 shows the thermal conductivity of ILs as a function of
temperature. Figure 5
Figure 5: Thermal conductivity (?) as a function of temperature for ILs
Electrical conductivity is one of the most main properties of
ILs as electrolyte materials.36The electrical conductivity (?) of
the ionic liquids was analytically measured with a conductivity
meter CTR80 (ZAG-CHEMIE). Electrical conductivity was
measured by means of the complex impedance method, using a
thermometer, under atmosphere for determined temperature.
The cell constant was determined by calibration after each sample
measurement using an aqueous 0.02 M KCl aqueous solution. The
?data for the considered aqueous RTIL systems were measured
for temperatures ranging from (298.15 to 348.15) K at normal
atmospheric pressure. Table 6 presented the obtained ? Table 8
Measurements: Molar conductivity of the ionic liquids ?
) was calculated from the ionic conductivity s (Sm-1
and the molar concentration C (kmolm-3
) according to the Eq (5).
The electrical conductivity presents linearly behaviour
with temperature for all ILs measured. Electrical conductivity
(?) values were fitted by the method of least squares using the
following equations (6).14
The plots showing the behaviour of the present ? data for
the studied solvent systems: [Bu3
] + DMSO, [Bu3
] + DMSO, [Bu3
] + DMSO, [Bu3
] + DMSO are shown in Fig 6. Figure 6
Figure 6: Electrical conductivity (?) as a function of temperature for ILs
Determination of Ho values of Lewis acidic ILs
A common and effective way to evaluate the acidity of
Bronsted acids was the Hammett method.37 In reported papers,
the measurement of the acidic scale of these acidic Bronsted
ILs was conducted on a UV-Vis spectrophotometer with a basic
indicator (para-nitroaniline).Increasing the acidic scale of the
acidic IL, the absorbance of the unprotonated form of the basic
indicator was decreased, whereas the protonated form of the
indicator was not observed because of its small molar absorptive
and its wavelength. Thus [I]/[HI] ([I] representsthe indicator)
ratio was determined from the measured absorbance differences
afteraddition of an acidic Bronsted IL, and then the Hammett
function, Ho, was calculated by using Eq 7
This value was regarded as the relative acidity of the
IL.8WherepK(I)aq was the pKa value of the indicator, [I] and [HI]
were respectively, the molar concentrations of the unprotonated
and protonated forms of the indicator, determined by UV-visible
spectroscopy. Figure 7
Figure 7: UV-Vis absorption spectra of ILs
Under the same concentration of 4-nitroaniline (10
mg/L, Pk(I)aq=pKa = 0.99) and Lewis ILs (0.1 mmol/L) in
dichloromethane, Hovalues of all Lewis ILs were determined. The
maximal absorbance of the unprotonated form of the indicator
was observed at 350 nm in dichloromethane. When Lewis IL
was added, the absorbance of theunprotonated form of the basic
indicator decreased (Figure 7 and Table 7). Table 10
Hammett acidity (Ho) of these Lewis ILs was calculated using
equations (7). As shown in Figure 7. Calculations suggest that the
Hammett acidity (Ho) of these ionic liquids follows the order:
A comparison between the experimental data for the physical
properties of the studied Lewis ILs at 25 °C has also made in Table
8. To the best of our knowledge, no literature data on densities (??),
dynamic viscosities (?), surface tension (s), electrical conductivity
(?), refractive indices (nD) and thermal conductivity (?), were not
previously available for five studied ILs. As is obvious from Table
8, the experimental data for[Bu3NBn][Al2Cl7], [Bu3NBn][Cu2Cl5], [Bu3NBn][Fe2Cl7], [Bu3NBn][Sn2Cl9]and [Bu3NBn][Zn2Cl5].
Thermo gravimetric analysis was applied to evaluate the
thermal properties of the Lewis IL sat a heating rate of 10°C/
min, under a nitrogen atmosphere. Figure 8 demonstrates
the respective TGA profiles and the corresponding thermo
analysis data, including the temperatures at which5% (T5) and
10% (T10) degradation occur. Char yield at 800°C and also
limiting oxygen index(LOI) based on Van Krevelen and Hoftyzer
equation(Equation (8)) is summarized in Table 9 .
From these data, it is clear that the [Bu3
] is stable
to300°C and introduction of inorganic particles in IL matrix
induced the thermal properties to rise. Table 11
Figure 8: TGA thermo grams of ILs under a nitrogen atmosphere at the
heating rate of 10 °C/min
aTemperature at which 5% weight loss was recorded by TGA
at a heating rate of 10°C/min under a nitrogen atmosphere.
bTemperature at which 10% weight loss was recorded by TGA
at a heating rate of 10°C/min under a nitrogen atmosphere.
cweight percentage of material left undecomposed after TGA
analysis at a temperature of 800°C under a nitrogen atmosphere.
dLimiting oxygen index (LOI) evaluating char yield at 800°C.
The data of physical properties on ionic liquids are necessary
for both theoretical research and industrial application. The
establishment of the databases in this respect will certainly
support the study and advance of ionic liquids. Due to the
development of green chemistry in recent years, researchers have
been interested in the application of ionic liquids can apply as
green catalysts, Room temperature ionic liquids (RTILs). Regard
to these unique features, In spite of the interesting feature and
practical importance of ILs, there are limited literature reports
on the accurate measurements of many of their fundamental
physical and chemical properties at various temperatures. Size
particle affected on physical chemistry properties of ILs. The
weight particle influenced on physical chemistry properties of
ILs. Structure ILs affected on properties physical chemistry of
ILs. Hydrogen bonding internal molecular influenced on physical
chemistry properties of ILs. Electrical charge particle influenced
on physical chemistry properties of ILs. Temperature affected on
properties physical chemistry of ILs. Principle HARD and SAFT
influenced on properties physical chemistry of ILs.
Thus, in this work, we have carefully measured several
important physical properties of Lewis ionic liquids: [Bu3NBn]
[Al2Cl7], [Bu3NBn][Cu2Cl5], [Bu3NBn][Fe2Cl7], [Bu3NBn][Sn2Cl9]
and [Bu3NBn][Zn2Cl5]over a wide range of temperature from
(298.15 to 363.15 K). Clearly, much more attention should be
paid on the measurement of physicochemical properties of Lewis
The measured densities, ??, and the dynamic viscosities, ?,
for the binary mixtures of [Bu3NBn][Fe2Cl7] with water at T =
(298.15to 363.15) K over the whole composition range are listed
in Tables 1 and 2.As can be seen, the density of all of the mixtures
with DMSO always decreases with temperature. A very good
linear correlation is observed for all compositions (r = 1), this
linear behavior with temperature.
The experimental viscosity results of Lewis ILs from this
study are in good agreement with the very scarce data from the
literature and are well represented by the VTF equation. At the
same temperature, [Bu3NBn][Fe2Cl7] have high very significantly
the viscosity of other Five ILs. Presencemetal atoms perhaps
make up high viscosity this IL than other ILs.Since the viscosities
of ILs are essentially effective by the van derWaals interactions
and H bonding,have reported the influence of metal atoms,
DMSOon the physical properties of [Bu3NBn][Fe2Cl7]. It hasbeen
shown that the presence of even low concentrations of chloride in
the [Bu3NBn][Fe2Cl7] substantially increases the viscosity.
Figure 5 shows the thermal conductivity of Lewis ILs as
a function of temperature.It can be seen that the thermal
conductivity of [Bu3NBn][Al2Cl7] is 0.68 Wm-1C-1. This indicates
that [Bu3NBn][Al2Cl7] is a relatively poor thermal conductor with
the thermal conductivity approximately of that of water at the
room temperature. Electrically conductive Lewis ILs is influence
of temperature. Besides, Thermo gravimetric analysis was
demonstrated to evaluate the thermal properties of the Lewis ILs.
Future Prospective of this work is following
Application as specific lubricants for engineering fluids.
Electrochemical Applications Ionic liquids, as possible
replacements for organic solvents in lithium ion rechargeable
batteries for laptops, mobile phones, biosensors, actuators,
solvents for electrochemical devices, super capacitors fuel
cells, dye-sensitized solar cells, and polymer electrolytes.
Coefficients of thermal expansion are defined by the following
Bronstedor Lewis acidic ionic liquids were used as solvents
and catalysts in many organic reactions such as esterification,
polymerization, alkylation, acylation, carbonylation, aldol
condensation, pinacol rearrangement, nitration, Koch reaction,
oxidation of alcohols.
Acidic Bronsted ionic liquids as environmental-friendly
solvents and catalysts with high activity and selectivity and
easily recovered were used to replace traditional liquid acids,
such as sulphuric acid and hydrochloric acid, in chemical
processes, especially acid catalysed.
Speeds of Sound u.
Self-diffusion coefficient of cation and anion in ionic liquid (D).
Chronoamperograms for ferrocene.
Excess Molar Volumes V E.
To recap, in comparison with the other ILs in that how do
the thermo physical properties and the most advantages and the
superiority of these system when compared to the ones reported
in the literature being easily produced and used in the various
We gratefully acknowledge the funding support received for
this project from the Isfahan University of Technology (IUT), IR
Iran, (Y.GH) and (A.R.H.), Grants.
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