Accepted Manuscript Preparation and characterization of amine (N-methyl diethanolamine)-based transition temperature mixtures (deep eutectic analogues solvents) Hosein Ghaedi, Ming Zhao, Muhammad Ayoub, Diana Zahraa, Azmi Mohd Shariff, Abrar Inayat PII: DOI: Reference:
S0021-9614(18)30737-7 https://doi.org/10.1016/j.jct.2018.12.014 YJCHT 5644
To appear in:
J. Chem. Thermodynamics
Received Date: Revised Date: Accepted Date:
12 July 2018 7 December 2018 8 December 2018
Please cite this article as: H. Ghaedi, M. Zhao, M. Ayoub, D. Zahraa, A. Mohd Shariff, A. Inayat, Preparation and characterization of amine (N-methyl diethanolamine)-based transition temperature mixtures (deep eutectic analogues solvents), J. Chem. Thermodynamics (2018), doi: https://doi.org/10.1016/j.jct.2018.12.014
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Preparation and characterization of amine (N-methyl diethanolamine)-based transition temperature mixtures (deep eutectic analogues solvents) Hosein Ghaedi a, Ming Zhao a,c, Muhammad Ayoub b,*, Diana Zahraab, Azmi Mohd Shariff b, Abrar Inayat d a
School of Environment, Tsinghua University, Beijing 100084, People’s Republic of China
b
Department of Chemical Engineering, Universiti Teknologi Petronas,32610 Bandar Seri Iskandar, Perak, Malaysia
c
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education, Beijing 100084, China d
Department of Sustainable & Renewable Energy Engineering,University of Sharjah, 27272Sharjah, United Arab Emirates *
Corresponding author: Email:
[email protected]; Telephone/fax: +6053687623.
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ABSTRACT In this study, three mixtures of methylyltriphenylphosphonium bromide (MTPPB) as hydrogen bond acceptor (HBA) and N-methyl diethanolamine (MDEA) as hydrogen bond donor (HBD) component was used to prepare transition temperature mixtures (TTMs) into different mole ratios of 1:7, 1:10 and 1:16 HBA/HBD. Two important physicochemical properties of TTMs such as density and refractive index were investigated at the atmospheric pressure and temperature ranges of (293.15-353.15) K and (293.15-343.15) K, respectively. The experimental density data were used to derive the molar volume, molecular volume, lattice energy and isobaric thermal expansion coefficients. With the help of experimental refractive index data, the electronic polarization, molar refraction, and free volume were calculated at the whole temperatures. Several empirical equations were used to correlate refractive indices such as an empirical equation and one-parameter equations (Dale–Gladstone, Eykman, Lorentz–Lorenz, Newton, Arago–Biot, and Oster). Finally, the response surface methodology (RSM) was applied to evaluate the effects of two main factors such as temperature and mole ratio on the density and refractive index of TTMs. Keywords: TTM; density; refractive index; RSM. 1. Introduction Deep eutectic solvents (DESs) as the green solvents are formed easily by mixing the hydrogen bond accepting (HBA) components, for example, halide salts and hydrogen bond donating (HBD) components such as amines, amides, carboxylic acids, and alcohols. The hydrogen bonding is the most interactions between HBA and HBD components. Abbott et al. [1] synthesized DESs by combination of quaternary ammonium salts and urea, in 2003. DESs are a wide liquid at the ambient temperature and have lower freezing point than their initial constituents, then the mixtureis eutectic. Further, DESs exhibit negligible volatility, non-flammable, high thermal stability and comprise non-expensive, non-toxic and biodegradable components [2-19]. Because of these advantages, DESs have gained more attention amongst researchers to apply in various areas such as CO2 capture [16, 19, 20], absorption of SO2 [21], drug solubilization vehicles [22], enhancing cellulose accessibility of corn stover [23], electrochemistry
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[24], DNA preservation and stabilization [25], biotransformations (enzyme reactions) [26], frontal polymerizations [27, 28],metal-catalysed organic reactions [29], biodiesel [30], aromatic hydrocarbons removal [31, 32], bioactive compounds [33, 34], and electrodeposition of metals [35, 36]. In recent times, a new kind of solvent called “Transition-Temperature Mixture” (TTM) has been reported by several research groups [37-53]. Unlike DESs which show a freezing temperature in DSC curve, this freezing point peak cannot appear in the DSC thermograms of TTMs. Indeed, DSC curves of TTMs show only the glass transition temperature [54]. Nevertheless, both DESs and TTMs may share the same
properties such as
. As suggested by Durand and et al [55], these solvents are considered as the subfamilies of low transition temperature mixtures. It is worthwhile to mention that some researcher suggested reasons behinds the formation of et al [41] specified that a way of preparation may lead to forming DES or
. Francisco
. In their study, it was suggested that
both of the initial components are mixed in the solid form at room temperature so as to promote contact between the solid crystals. However, in our study, HBA was solid and HBD was liquid; thus, mixture with one liquid component may form a
Another postulate was that high viscosity of final solvent at room temperature may
prevent the nucleation and crystal growth as suggested by Durand et al. [22]. But all solvents in this study had low viscosity at room temperature particularly solvents with the higher mole ratio. Therefore, these two assumptions are strongly rejected and it is needed more investigations to find the reasons behind this phenomenon. have been used for different purposes. Ma et al. [38] selected Choline Chloride-Glycolic Acid mixture as the entrainer for simulation of ethanol-water systems separation. Rodríguez et al. [39] evaluated several choline chloride-based
with different acids components as s potential entrainers for extractive distillation. Zubeir et
al. [42] examined the several mixtures for CO2 absorption purpses such as lactic acid and tetraethylammonium chloride /tetramethylammonium chloride / tetrabutylammonium chloride. Karageorgou et al. [43] used sodium acetate-based
for extraction of polyphenols from Moringa oleifera leaves.
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In order to extract the antioxidant phenolics from industrial cereal solid wastes, Kottaras et al. [44] synthesized several amino acids, L-lactic acid, choline chloride-based TTMs and studied the efficiency of these mixtures. Tereshatov et al. [46] used the mixture of tetraheptylammonium chloride and ibuprofen for metal extraction. Dedousi et al. [49] tested the efficient ability of mixture of glycerol and sodium-potassium tartrate to extract polyphenolic substances from olive leaves. Yiin et al. [50, 51] characterized the mixtures of malic acid and sucrose/monosodium glutamate/choline chloride for biomass delignification. Liu et al. [52] used the oxalic acid and choline chloride for lignin modification. Bao et al. [53]investigate the electrodeposition of zinc using mixture of choline chloride and lactic acetic. In our previous work, the refractive index and density and potassium-based TTMs and ternary transition temperature mixtures have been reported at different temperatures and the effects of temperature and mole ratio on these properties were investigated [54]. In this work, TTMs were prepared into different mole ratios by mixing HBA, for instance, methyltriphenylphosphonium bromide (MTPPB) with HBD such as N-methyl diethanolamine (MDEA). The mole number of HBA was constant in mixtures (1 mole) while those of HBD varied from 7, 10 and 16 moles in the mixtures. The experimental density and refractiveindex of TTMs and MDEA were measured at different temperature ranges up to 353.15 K and 343.15 K, respectively. In order to derive to the isobaric thermal expansion coefficients, molar volume, and molecular volume of TTMs, the density values were used at the whole studied temperatures. The refractive index data were used to determine the molar refraction, free volume, and electronic polarization of TTMs. Finally, several empirical equations were used to relate density and refractive index data, for instance, Dale–Gladstone, Eykman, Lorentz–Lorenz, Newton, Arago–Biot, and Oster.
2. Material and methods 2.1 Chemicals Methyltriphenylphosphonium bromide (MTPPB) was provided by Angene International Limited. N-methyl diethanolamine (MDEA) was obtained from Merck Sdn Bhd with the purity of (>0.98 mass fraction). Table 1 contains a list of the chemicals used in this work together with the linear formula, CAS number and their purity.
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Table 2 presents the composition of TTMs together with mole ratios, symbols and molecular mass of each constituent/ TTM. All samples were kept in a controlled environment to avoid the moisture and any contamination. Figure 1 depicts the molecular structure of MTPPB and MDEA. Figure 2 illustrates the appearance of TTMs. Table 1 Details of samples employed in this work. Table 2 The composition of TTMs together with water content and glass transition temperature. Figure 1. The chemical structure of the initial components. Figure 2. Appearance of TTMs in this work.
2.2 TTM preparation TTMs were prepared easily by heating the mixture of MTPPB (solid) + MDEA (liquid). The amount of MTPPB was constant (one mole) while that of MDEA was changed in the mixture (7 moles, 10 moles and 16 moles). Under a fume hood, a hot plate magnetic stirrer was used to heat the mixtures inside capped bottles up to 373 K and at 400 rpm until homogeneous and uniform liquid without any precipitate appeared, as shown in Figure 2. According to Figure 2, the crystal phase formed 24 hours after preparation of MTPPB-MDEA into mole ratio of 1:4. TTM1 and TTM2 were yellowish-brown and TTM3 was colourless. All samples were kept in the fume hood and humidity controlled place to prevent moisture further used to measure density and refractive index.
2.3 Characterization A Karl-Fischer Coulometric titrator (Mettler Toledo C30) was applied to detect the water content of TTMs. The water content was found to be less than 0.003, as listed in Table 2 based on the mass fraction. A Mettler-Toledo differential scanning calorimetry (DSC 1) was employed for measuring the glass transition temperatures. The procedure of how the instrument works is available in the previous work [54]. The MettlerToledo STARe Software version 9.30 was used for evaluation of data. In order to calibrate the DSC, Indium was used through its melting point. The sample was first cooled from 25 °C to −150 °C and heated from −150 °C to 25
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°C at a rate 10 °C·min-1 followed by cooling to −150 °C, and finally heated back to 25 °C with the same heating rate. The uncertainty in temperature was found to be ±0.2 °C Density measurements were conducted by a U-tube Anton Par density meter (DMA 4500M) at a temperature range from 293.15 K to 353.15 K and atmospheric pressure. The accuracy of density measurement and temperature were ±5×10-5 g·cm-3 and ±0.01 K, respectively. Acetone and Millipore water were used to clean the U-shaped tube of density meter and then was tube dried by using an air blower to avoid any effect moisture content on the final results. The final reported density values are the average of repeated three times for each sample. In order to determine the refractive index of TTMs and HBD, an Anton Par (digital Abbemat automatic refractometer, model WR) was used at a wavelength of 589.3 nm, temperature from 293.15 K to 343.15 K, and atmospheric pressure. The temperature accuracy was ±0.03 K. Before starting measurements, prism face should be cleaned with the acetone and then dried carefully because the sediments can affect the results. Similar to density measurement, the average of repeated three times for each sample was reported as the final refractive index data. The measurements were conducted at a temperature range from 293.15 K to 353.15 K and. 2.4 3.5 Response surface methodology (RSM) It is important to illustrate the influence of the controlled factors on the thermophysical properties of solvents. The response surface methodology (RSM) is the effective method of design of experiment (DOE), which can be used for different purposes such as model development, optimizing processes and evaluating the relative significance of parameters and their effect on the response [56]. Therefore, DOE was applied using RSM to illustrate the effect of temperature and mole ratio on the density and refractive index of TTMs. The input parameters were temperature and mole ratio. The density and refractive index were responses. For the density response, the temperature and mole ratio had 13 and 3 levels, respectively. While the levels of temperature and mole ratio are 11 and 3, in order, for the refractive index response. The details of the designs are presented in Table 3. For both responses, linear models were selected to study the effect of aforementioned factors which had probability value less than 0.01 (p-value
