Research Article Open Access
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
*Corresponding author: 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.
AbstractTop
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.
IntroductionTop
Large attention is being strained towards Ionic Liquids (ILs) as alternatives for usual molecular solvents used in organic synthesis and catalytic reactions [1]. 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[2]. 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 [3]. multiphase bioprocess operations [4] and liquidliquid separations [5] electrolytes for batteries and fuel cells [6] stationary phases in gas chromatography[7] mobile phase additives in liquid chromatography[8] and electrolyte additive sin capillary electrophoresis (CE) [9].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 [10]. 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 [12].

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 [13]. 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 [14].
Experimental SectionTop
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 literature [15].

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 [16]. 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, 91, 58.

[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 [17], [18]. This contains fungi, bacteria, algae, enzymes, rat cell line, fish, and so forth.

Stock and colleagues highlighted that the consequence of ionic liquids on acetyl cholinesterase [19]. 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 [20]. 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 [21].

Leukemia rat cell line IPC-81 was also used to detect the cytotoxic effect of commercially accessible anions [22]. The major anion effect was found under the test system as following respectively.

[Bu3NBn][Cu2Cl5]˃[Bu3NBn][Fe2Cl7]˃[Bu3NBn][Al2Cl7]˃ [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 [23]. 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 [24]. 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 [25]. 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 [26]. 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 [27]. 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 [28].

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 [2,29].

Benzene- Dichlorom cthane- Carbon Tetrachloride- Hexane> Cyclohexane- Tleptane- Ethylene Glycol- Toluene> Water- Acetone- Etheanol- 2-Propanol

[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] [OTs]
Freshwater
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
Seawater
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 [31].
 Test Pass level after 10 days Biodegradability in seawater (TG 306) >50% DOC removal Shake flask and closed bottle variants >45% ThOD
Table 2: OECD testing guidelines
 Test/ ILs [Bu3NBn] [Bu3NBn] [Bu3NBn] [Bu3NBn] [Bu3NBn] Pass level after 5 days [Al2Cl7] [Cu2Cl5] [Fe2Cl7] [Sn2Cl9] [Zn2Cl5] Dissolved Organic Carbon (DOC) 43%DOC-removal 40% 60% 37% 50% CO2 Evolution Test (TG301B) 50%ThCO2 45% 50% 40% 33% Manometric respirometry test (TG 301F) 40%ThOD 50% 45% 50% 60%
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 biodegradation kinetics.
• Half-saturation constant
• The maximum exact growth rate [31].

One other arranged test for inherent biodegradation of chemical compounds in the soil exists for ILs is in the OECD TG, Table 1.
Biodegradation of imidazolium-based [Bu3NBn][Cu2Cl5]˃ [Bu3NBn][Fe2Cl7]˃[Bu3NBn][Al2Cl7]˃[Bu3NBn][Sn2Cl9]˃ [Bu3NBn] [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 ± 1.6% degradation.
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
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 (r2> 0.999).

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) [32].
Where fitting parameter B and A are related to the coefficient of volume expansion (gcm-3 K-1) and extrapolated density at 0K (gcm-3), 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
Viscosity
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 mPa
• s. 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) [32].
• 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) [34].
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
Refractive Index
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
Surface Tension
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
Thermal conductivity
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 almost±2%.

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
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 ? (m2Smol-1) 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: [Bu3NBn][Al2Cl7] + DMSO, [Bu3NBn] [Cu2Cl5] + DMSO, [Bu3NBn][Fe2Cl7] + DMSO, [Bu3NBn][Sn2Cl9] + DMSO, [Bu3NBn][Zn2Cl5] + 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: [Bu3NBn] [Cu2Cl5]>[Bu3NBn][Sn2Cl9]>[Bu3NBn][Al2Cl7]>[Bu3NBn] [Zn2Cl5]> [Bu3NBn][Fe2Cl7].

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].
Thermal properties
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 [17].
From these data, it is clear that the [Bu3NBn][Fe2Cl7] 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.
ConclusionsTop
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 ionic liquids.

Bu3NBn][Cu2Cl5]?[Bu3NBn][Fe2Cl7]?[Bu3NBn][Al2Cl7]? [Bu3NBn][Sn2Cl9]?[Bu3NBn][Zn2Cl5]

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 equation: $\alpha _p=-1/\rho \left(\partial \rho /\partial T\right)_p$
• 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).
• Cyclic voltammograms.
• 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 temperature.
• AcknowledgmentsTop
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.
ReferencesTop
1. P Wasserscheidt, T Weldon. Ionic Liquids in Synthesis. 2003;Wiley-VCH;New York.
2. Wood N, Stephens G. Accelerating the discovery of biocompatible ionic liquids. Physical Chemistry Chemical Physics. 2010;12(8):1670-1674.
3. (a) J Dupont, RF de Souza, PAZ Suarez. Chem Rev. 2002;102:3667. (b) P Wasserscheidt, W Keim, Angew. Chem Int. Ed. 2000;39: 3772. (c) MJ Earle, KR Seddon, Pure Appl. Chem 2000;72:1391.
4. SG Cull, JD Holbrey, V Vargas-Mora, KR Seddon, GJ Lye. Biotechnol Bioeng. 2000;69:227.
5. (a) JG Huddleston, HD Willauer, RP Swatloski, AE Visser, RD Rogers.Chem. Commun. 1998,1765.(b) AG Fadeev, MM Meagher.Chem. Commun.2001;295.
6. AE Visser, RP Swatloski, RD Rogers. Green Chem. 2000; 2:1.
7. (a) F Pachole, HT Butler, CF Poole. Anal.Chem. 1982, 54: 1938. (b) DW Armstrong, JL Andersen, J Ding, T Welton. J Am Chem Soc. 2002,124:14247. (c) A Berthod, L He, DW Armstrong. Chromatographia. 2000;53: 63. (d) A Heintz, DW Kulikov, SP Verevkin, J Chem Eng. Data. 2002;47:894.
8. (a) L He, W Zhang, L Zhao, X Liu, S Jiang. J Chromatogr A.2003;1007:39. (b) R Kaliszan, MP Marszall, MJ Markuszewski, T Baczek, J Pernak, J Chromatogr. A. 2004;1030:263. (c) X Xiao, L Zhao, X Liu, S Jiang. Anal Chim Acta. 2004;519:207.
9. (a) EG Yanes, SR Gratz, AM Stalcup.Analyst. 2000;125:1919. (b) EG Yanes, SR Gratz, MJ Baldwin, SE Robinson, AM Stalcup. Anal Chem. 2001;73:3838. (c) M Vaher, M Koel, M Kaljurand. Chromatographia. 2001;53:S-302. (d) M Vaher, M Koel, M Kaljurand. Electrophoresis.2002;23:426. (e) M Vaher, M Koel, M Kaljurand, J Chromatogr A. 2002;979:27. (f) R Kuldvee, M Vaher, M Koel, M Kaljurand.Electrophoresis. 2003;24:1627. (g) M Vaher, M Kaljurand, J Chromatogr A. 2003;990:225. (h) SM Mwongela, A Numan, NL Gill, RA Agbaria, IM Warner, Anal Chem. 2003;75:6089.
10. (a) H Sakaebe, H Matsumoto. Electrochem. Commun. 2003;5:594. (b) PC Howlett, DR MacFarlane, AF Hollenkamp. Electrochem Solid-State Lett. 2004;7:A97. (c) H Matsumoto, M Yanagida, K Tanimoto, M Nomura, Y Kitagawa, Y Miyazaki. Chem Lett. 2000;922.
11. J Sun, DR MacFarlane, M Forsyth. Ionics. 1997;3:356.
12. J Sun, M Forsyth, DR MacFarlane. J Phys Chem B. 1998;102:8858.
13. (a) AB Pereiro, E Tojo, A Rodriguez, J Canosa, J Tojo. J Chem Thermodyn. 2006;38:651.(b)AB Pereiro, F Santamarta, E Tojo, A Rodriguez, J Tojo. J Chem Eng. Data. 2006;51:952. (c) AB Pereiro, E Tojo, A Rodriguez, J Canosa, J Tojo. Green Chem. 2006;8:307.(d) AB Pereiro, JL Legido, A Rodriguez. J Chem. Thermodyn. 2007;39:1168.
14. BJ Cox S, Jia ZC Zhang, JG Ekerdt. Polymer Degradation and Stability. 2011;96:426e431.
15. AR Hajipour, F Rafiee. Organic Preparations and Procedures International. 2010;42:285-362.
16. R Zhang, X Meng, Z Liu, J Meng, C Xu, Ind Eng Chem Res. 2008;47:8205.
17. Matzke M, Stolte S, Thiele K, Juffernholz T, Arning J, Ranke J, Welz-Biermann U, Jastorff B. The influence of anion species on the toxicity of 1-alkyl-3-methylimidazolium ionic liquids observed in an (eco)toxicological test battery. Green Chemistry. 2007;9(11):1198-1207.
18. Pham TPT, Cho C-W, Yun Y-S. Environmental fate and toxicity of ionic liquids: A review. Water Research. 2010;44(2):352-372.
19. Stock F, Hoffmann J, Ranke J, Stormann R, Ondruschka B, Jastorff B. Effects of ionic liquids on the acetylcholinesterase - a structure-activity relationship consideration. Green Chemistry. 2004;6:286-290.
20. Couling DJ, Bernot RJ, Docherty KM, Dixon JK, Maginn EJ. Assessing the factors responsible for ionic liquid toxicity to aquatic organisms via quantitative structure-property relationship modeling. Green Chemistry. 2006;8(1):82-90.
21. Ranke J, Molter K, Stock F, Bottin-Weber U, Poczobutt J, Hoffmann J, et al. Biological effects of imidazolium ionic liquids with varying chain lengths in acute Vibrio fischeri and WST-1 cell viability assays. Ecotoxicol Environ Saf. 2004;58(3):396-404.
22. Stolte S, Arning J, Bottin-Weber U, Matzke M, Stock F, Thiele K, et al. Anion effects on the cytotoxicity of ionic liquids. Green Chemistry. 2006;8(7):621-629.
23. Bernot RJ, Brueseke MA, Evans-White MA, Lamberti GA. Acute and chronic toxicity of imidazolium-based ionic liquids on Daphnia magna. Environ Toxicol Chem. 2005;24(1):87-92.
24. Yu M, Wang S-H, Luo Y-R, Han Y-W, Li X-Y, Zhang B-J, et al. Effects of the 1-alkyl-3-methylimidazolium bromide ionic liquids on the antioxidant defense system of Daphnia magna. Ecotoxicol Environ Saf. 2009;72(6):1798-1804. doi: 10.1016/j.ecoenv.2009.05.002
25. Cho C-W, Jeon Y-C, Pham TPT, Vijayaraghavan K, Yun Y-S. The ecotoxicity of ionic liquids and traditional organic solvents on microalga Selenastrum capricornutum. Ecotoxicol Environ Saf. 2008;71(1):166-171.
26. Cho C-W, Jeon Y-C, Pham TPT, Yun Y-S. Influence of anions on the toxic effects of ionic liquids to a phytoplankton Selenastrum capricornutum. Green Chemistry. 2008;10(1):67-72.
27. Konnecker G, Regelmann J, Belanger S, Gamon K, Sedlak R. Environmental properties and aquatic hazard assessment of anionic surfactants: Physico-chemical, environmental fate and ecotoxicity properties. Ecotoxicol Environ Saf. 2011;74(6):1445-1460. doi: 10.1016/j.ecoenv.2011.04.015
28. Dyer SD, Lauth JR, Morrall SW, Herzog RR, Cherry DS. Development of a Chronic Toxicity Structure-Activity Relationship for Alkyl Sulfates. Environmental Toxicology and Water Quality. 1997;12(4):295-303.
29. Alfonsi K, Colberg J, Dunn PJ, Fevig T, Jennings S, Johnson TA, et al. Green chemistry tools to influence a medicinal chemistry and research chemistry based organisation. Green Chemistry. 2008;10(1):31-36.
30. OECD. Revised Introduction to the OECD Guidelines for Testing of Chemicals. Section 3. 2006;OECD Publishing.
31. http://www.oecd.org/chemicalsafety/testing/oecdguidelinesforthetestingofchemicals.htm
32. Andrew Jordan, Nicholas Gathergood. Biodegradation of ionic liquids - a critical review. Chem. Soc. Rev. 2015;44(22):8200- 8237.
33. AB Pereiro, P Verdi a, E Tojo, AR guez. J Chem Eng Data. 2007;52:377-380.
34. (a) I Stepniak, E Andrzejewska. Electrochim Acta. 2009;54:5660. (b) Wilkes JS. Properties of ionic liquid solvents for catalysis. J Mol Catal A Chem. 2004;214,11-17. (c) OO Okoturo, JJ Vandernoot, J Electroanal Chem. 2004;568:167-181. (d) E Gomez, B Gonzalez, Calvar, E Tojo, A Dominguez. J Chem Eng Data. 2006;51:2096-2102.
35. (a) KR Seddon, AS Starck, MJ Torres. ACS Symp Ser. 2004;No. 901. (b) JS Wilkes, J Mol Catal A Chem. 2004; 214: 11-17. (c) OO Okoturo, JJ Vandernoot, J Electroanal Chem. 2004;568:167-181.
36. (a) NM Yunus, MIA Mutalib, Z Man, MA Bustam, T Murugesan. J Chem Thermodyn. 2010;42:491-495. (b) A Muhammad, MIA Mutalib, CD Wilfred, T Murugesan, A Shafeeq. J Chem Thermodyn. 2008,40:1433-1438.
37. DW Van Krevelen, PJ Hoftyzer. Properties of polymers. 1976;Elsevier:Amsterdam.

Listing : ICMJE