Low-cost Solvent Research Articles

Triethylammonium hydrogen sulfate ionic liquid as a low-cost solvent: A short review of synthesis, analysis and applications

This review does not attempt to be comprehensive, but it briefly introduces triethylammonium hydrogen sulfate ionic liquid ([N2220][HSO4] IL), which has been regarded as a low-cost solvent. It provides guidance regarding the synthesis procedures of the IL and several routine assessments for gaining insight into the properties of the IL. The review also selects examples of applications wherein the IL has been applied. It is hoped that the review will stimulate more research utilising the [N2220][HSO4] IL across various disciplines of science and engineering.

Crystal growth, physical properties and computational insights of semi-organic non-linear optical crystal diphenylguanidinium perchlorate grown by conventional solvent evaporation method

A splendid nonlinear optical single crystals diphenylguanidinium perchlorate (DPGP) was lucratively grown by low cost solvent evaporation method with the dimensions of 8 × 4 × 2 mm3. Structural and morphological studies of grown crystal were confirmed using X-ray diffraction studies. The presence of diverse functional groups was identified using FTIR and RAMAN studies. The molecular structure of a grown crystal was inveterate by NMR studies. The optical transmittance of DPGP crystal was analyzed using UV–vis-NIR studies. Photoluminescence spectrum shows sharp, well defined emission peak at 388 nm. Thermal studies assign that adduct is stable with the melting point of 164 °C. Microhardness studies declare that DPGP crystal belongs to the soft material class and their yield strength and elastic stiffness constant values were evaluated. Photoconductivity studies revealed the negative photoconductive nature of DPGP crystal. Second harmonic generation (SHG) efficiency of the DPGP crystal was 1.4 times that of potassium dihydrogen phosphate. Etching studies were carried out for different etching time. The dielectric studies were performed at different frequency. Laser damage threshold properties of DPGP crystal were examined using Nd:YAG laser system. The HOMO-LUMO energy gap evident the charge transfer interaction of the molecule. The calculated first order hyperpolarizability value is 5 times greater than that of urea. Thus, the grown DPGP single crystals are well suited for NLO device fabrications.

Layered microporous polymers by solvent knitting method.

Two-dimensional (2D) nanomaterials, especially 2D organic nanomaterials with unprecedentedly diverse and controlled structure, have attracted decent scientific interest. Among the preparation strategies, the top-down approach is one of the considered low-cost and scalable strategies to obtain 2D organic nanomaterials. However, some factors of their layered counterparts limited the development and potential applications of 2D organic nanomaterials, such as type, stability, and strict synthetic conditions of layered counterparts. We report a class of layered solvent knitting hyper-cross-linked microporous polymers (SHCPs) prepared by improving Friedel-Crafts reaction and using dichloroalkane as an economical solvent, stable electrophilic reagent, and external cross-linker at low temperature, which could be used as layered counterparts to obtain previously unknown 2D SHCP nanosheets by method of ultrasonic-assisted solvent exfoliation. This efficient and low-cost strategy can produce previously unreported microporous organic polymers with layered structure and high surface area and gas storage capacity. The pore structure and surface area of these polymers can be controlled by tuning the chain length of the solvent, the molar ratio of AlCl3, and the size of monomers. Furthermore, we successfully obtain an unprecedentedly high-surface area HCP material (3002 m2 g-1), which shows decent gas storage capacity (4.82 mmol g-1 at 273 K and 1.00 bar for CO2; 12.40 mmol g-1 at 77.3 K and 1.13 bar for H2). This finding provides an opportunity for breaking the constraint of former knitting methods and opening up avenues for the design and synthesis of previously unknown layered HCP materials.

Synthesis of Barium Titanate Using Deep Eutectic Solvents.

Novel synthetic routes to prepare functional oxides at lower temperatures are an increasingly important area of research. Many of these synthetic routes, however, use water as the solvent and rely on dissolution of the precursors, precluding their use with, for example, titanates. Here we present a low-cost solvent system as a means to rapidly create phase-pure ferroelectric barium titanate using a choline chloride-malonic acid deep eutectic solvent. This solvent is compatible with alkoxide precursors and allows for the rapid synthesis of nanoscale barium titanate powders at 950 °C. The phase and morphology were determined, along with investigation of the synthetic pathway, with the reaction proceeding via BaCl2 and TiO2 intermediates. The powders were also used to create sintered ceramics, which exhibit a permittivity maximum corresponding to a tetragonal-cubic transition at 112 °C, as opposed to the more conventional temperature of ∼120 °C. The lower-than-expected value for the ferro- to para-electric phase transition is likely due to undetectable levels of contaminants.

Design rules of ionic liquids tasked for highly efficient fuel desulfurization by mild oxidative extraction

The deep desulfurization of petroleum-based fuels using oxidative extraction processes has been hampered by the lack of suitable solvent systems and by the poor availability of inexpensive and efficient catalysts. As a strategy to address this limitation, the present study evaluates a number of hydrophilic and hydrophobic ionic liquids (ILs) for the oxidative extraction of dibenzothiophene (DBT) and other aromatic sulfur compounds (e.g., thiophene, TS, benzothiophene, BT, and 4,6-dimethyldibenzothiophene, DMDBT) from n-octane using H2O2 as the oxidant and V2O5 as the catalyst. Our findings are significant for petroleum desulfurization and suggest that ILs for effective sulfur removal will typically comprise low basicity/nucleophilicity anions paired to cations possessing some hydrophilic character. Among a number of suitable ILs identified for this application, [Choline][Tf2N] is particularly promising as a relatively low-cost solvent ideal for use in oxidative extraction to desulfurize fuel. The [Choline][Tf2N]–V2O5 system afforded essentially quantitative removal of DBT, BT, and DMDBT at room temperature, even for initial sulfur levels as high as 3000ppm. This advance enables a highly efficient and cost-effective desulfurization process that has a promising industrial application for producing ultra-low-sulfur fuel.

Aqueous solution-derived CuMn2O4 ceramic films for spectrally selective solar absorbers

By replacing absolute ethanol, water was used as a ubiquitous and low-cost solvent to dissolve metal nitrates and organic additives to obtain a precursor solution that showed long-term stability and reproducibility. This precursor solution was used to deposit a CuMn2O4 ceramic film on a stainless steel substrate using the convenient and inexpensive sol-gel dip-coating technique. The X-ray diffraction (XRD) profile of the ceramic film annealed for 1h at 450°C was found to coincide with that of crystalline CuMn2O4 in the JCPDS database. The CuMn2O4 ceramic film obtained at an annealing temperature of 500°C exhibited excellent solar absorptance (αs=0.905) and thermal emittance (ε100=0.120). By optimizing the deposition parameters, we systematically investigated the effect of the chemical components, surface texture, and thickness of the ceramic film on its optical properties. Subjected to a thermal stability test at 252°C, the CuMn2O4 ceramic film showed good thermal stability with performance criterion (PC) values below 0.05.

Thermodynamics of Imidazolium-Based Ionic Liquids Containing PF6 Anions.

Imidazolium-based ionic liquids (ILs) with PF6(-) anions are considered as low-cost solvents for separation processes, but they exhibit restricted thermal stabilities. Reliable measurements of vaporization thermodynamics by conventional methods have failed. In this work, we applied a quartz-crystal microbalance method to determine for the first time the absolute vapor pressures for the [Cnmim][PF6] family, with n = 2, 4, 6, 8, and 10, in the temperature range 403-461 K. An absence of decomposition of ILs in experimental conditions was determined by the attenuated total reflection-infrared spectroscopy. The consistency of the experimental results within the homologous series was established through enthalpy and entropy analyses of the liquid and gas phases as well as by molecular dynamics simulations.

Methyltrichlorosilane polysiloxane filament growth on glass using low cost solvents and comparison with gas phase reactions

Fluorine free, transparent, superhydrophobic polysiloxane filament coatings on glass were successfully prepared using methyltrichlorosilane (MTCS) both via liquid phase reactions using standard hydrocarbons in an open system and gas phase reactions under controlled humidity environment. Wettability, morphology and transparency of the obtained coatings were characterized by contact angle measurements, scanning electron microscopy and UV–vis spectrometer transmittance tests respectively. Superhydrophobic polysiloxane nanofilament coatings were obtained for the first time in an open system using standard petroleum ether having advancing contact angle values (θa) between 156 and 168°. Surfaces having contact angle hysteresis as low as 9° were obtained by varying the reaction time and MTCS concentration in petroleum ether. On the other hand, the relative humidity was found to be the most important factor when compared with the factors such as reaction time and silane concentration to change the morphology and the contact angles of the coatings in the gas phase where 38% RH was found to be the optimum for the growth of polysiloxane nanofilament coatings on glass. Polysiloxane nanofilaments having diameters ranging from 34 up to 42nm and θa values between 166 and 168° were obtained in the gas phase reactions. The transparency of the surfaces prepared in the gas phase was higher than the ones prepared in the liquid phase.

Surface Tension Components Based Selection of Cosolvents for Efficient Liquid Phase Exfoliation of 2D Materials.

A proper design of direct liquid phase exfoliation (LPE) for 2D materials as graphene, MoS2 , WS2 , h-BN, Bi2 Se3 , MoSe2 , SnS2 , and TaS2 with common cosolvents is carried out based on considering the polar and dispersive components of surface tensions of various cosolvents and 2D materials. It has been found that the exfoliation efficiency is enhanced by matching the ratio of surface tension components of cosolvents to that of the targeted 2D materials, based on which common cosolvents composed of IPA/water, THF/water, and acetone/water can be designed for sufficient LPE process. In this context, the library of low-toxic and low-cost solvents with low boiling points for LPE is infinitely enlarged when extending to common cosolvents. Polymer-based composites reinforced with a series of different 2D materials are compared with each other. It is demonstrated that the incorporation of cosolvents-exfoliated 2D materials can substantially improve the mechanical and thermal properties of polymer matrices. Typically, with the addition of 0.5 wt% of such 2D material as MoS2 nanosheets, the tensile strength and Young's modulus increased up to 74.85% and 136.97%, respectively. The different enhancement effect of 2D materials is corresponded to the intrinsic properties and LPE capacity of 2D materials.

Ammonium-based deep eutectic solvents as novel soil washing agent for lead removal

Deep eutectic solvents (DESs) are a new class of biodegradable and low cost solvents analogous to ionic liquids. In this study, DESs have been used to remove lead from a landfill soil for the first time. The DESs used in this study were prepared by mixing choline chloride, a quaternary ammonium salt with different hydrogen bond donors such as fructose, sucrose, glycerol and ethylene glycol. A natural biodegradable surfactant saponin extracted from soapnut fruit pericarp, was mixed with DESs to enhance their efficiency. The 10% solution of fruit-based DESs containing fructose and sucrose demonstrated lead removal of about 31% and 25% respectively, which increased on addition of saponin. Up to 72% Pb could be removed with a combination of 40% fructose-based DES and 1% saponin or 10% fructose-based DES and 2% saponin. For synthetic DESs containing glycerol and ethylene glycol, saponin addition resulted in marked improvement of up to 54%. Mildly alkaline DESs supplied H+ acting as Lewis acid which replaced the lead cations from the organic carbon electron donors. Slightly alkaline DESs performed better when mixed with acidic saponin solution which supplied H+. This study will open up new possibilities into the application of natural compound based DESs for soil remediation.

English

English

The use of deuterated ethyl acetate in highly concentrated electrolyte as a low-cost solvent for in situ neutron diffraction measurements of Li-ion battery electrodes

A low-cost deuterated electrolyte suitable for in situ neutron diffraction measurements of normal and high voltage Li-ion battery electrodes is reported here. Li[Ni0.4Mn0.4Co0.2]O2/graphite (NMC(442)/graphite) pouch cells filled with 1:0.1:2 (molar ratio) of lithium bis(fluorosulfonyl) imide (LiFSi):LiPF6: ethyl acetate (EA) and LiFSi:LiPF6:deuterated EA (d8-EA) electrolytes were successfully cycled between 2.8V and 4.7V at 40°C for 250h without significant capacity loss, polarization growth, or gas production. The signal-to-noise ratio of neutron powder diffraction patterns taken on NMC(442) powder with a conventional deuterated organic carbonate-based electrolyte and filled with LiFSi:LiPF6:d8-EA electrolyte were virtually identical. Out of all the solvents widely available in deuterated form tested in highly-concentrated systems, EA was the only one providing a good balance between cost and charge-discharge capacity retention to 4.7V. The use of such an electrolyte blend would half the cost of deuterated solvents needed for in situ neutron diffraction measurements of Li-ion batteries compared to conventional deuterated carbonate-based electrolytes.

Synergistic action of deep eutectic solvents and cellulases for lignocellulosic biomass hydrolysis

The increased awareness of environmental and economic issues has led many researchers to seek green and low-cost solvent for the conversion of lingocellulosic biomass to bioenergy. In this context, deep eutectic solvents, a new class of ionic liquids, have been regarded as greener substitute to conventional solvents for pretreatment of biomass. This paper is concerned with the stability and synergicity action of deep eutectic solvents for the digestion of biomass. The stability was studied by incubating commercial cellulases to different concentration of ethylene glycol–choline chloride-based deep eutectic solvent. The synergistic tests were studied by performing enzymatic saccharification after pretreatment of rice husk with deep eutectic solvent at various temperatures. The stability test showed that, the commercial cellulase activity retained more than 90% of relative activity after 1 hour of incubation in 10(%,v/v) deep eutectic solvent at 30°C. The prepared deep eutectic solvent in combination with commercial cellulases study showed that the higher pretreatment temperature improved the production of simple sugar from rice husk.

Graphene/silicon nanocomposite anode with enhanced electrochemical stability for lithium-ion battery applications

A graphene/silicon nanocomposite has been synthesized, characterized and tested as anode active material for lithium-ion batteries. A morphologically stable composite has been obtained by dispersing silicon nanoparticles in graphene oxide, previously functionalized with low-molecular weight polyacrylic acid, in eco-friendly, low-cost solvent such as ethylene glycol. The use of functionalized graphene oxide as substrate for the dispersion avoids the aggregation of silicon particles during the synthesis and decreases the detrimental effect of graphene layers re-stacking. Microwave irradiation of the suspension, inducing reduction of graphene oxide, and the following thermal annealing of the solid powder obtained by filtration, yield a graphene/silicon composite material with optimized morphology and properties.Composite anodes, prepared with high-molecular weight polyacrylic acid as green binder, exhibited high and stable reversible capacity values, of the order of 1000 mAh g−1, when cycled using vinylene carbonate as electrolyte additive. After 100 cycles at a current of 500 mA g−1, the anode showed a discharge capacity retention of about 80%. The mechanism of reversible lithium uptake is described in terms of Li–Si alloying/dealloying reaction. Comparison of the impedance responses of cells tested in electrolytes with or without vinylene carbonate confirms the beneficial effects of the additive in stabilizing the composite anode.

Determination of organochlorine pesticide residues in rice by gas chromatography-mass spectrometry following directly suspended droplet microextraction

A simple and efficient approach as directly suspended droplet microextraction (DSDME) was applied to the determination of organochlorine pesticides in rice prior to analysis by gas chromatography-mass spectrometry (GC-MS). The extraction parameters such as organic solvent type and volume, extraction time, and ion strength were systemically optimized. Furthermore, method linearity, recovery, limits of detections (LODs), and precision were also investigated. The proposed method provided good linearity (R2 = 0.9900–0.9996). LODs determined by GC-MS in selected-ion monitoring (SIM) mode were between 0.0005–0.033 mg/kg. The relative standard deviations (RSDs) varied from 2.0–14.0%, while the enrichment factors were between 221–550. The experimental results suggest that DSDME followed by GC-MS is a simple, sensitive, low-cost and little solvent consumption for the determination of organochlorine pesticides in rice, and has high enrichment factors suitable to trace analysis.

Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering

In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2–1.5wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications.

An efficient green procedure for the synthesis of bis (indolyl) methanes in water

In this work, a green, simple and highly efficient procedure for the synthesis of bis(indolyl)methanes is described. The condensation of indoles with carbonyl compounds catalyzed by citric acid in water affords bis(indolyl)methanes in high yields and relatively short reaction times. The advantages of this method are using of water as a low cost solvent and efficient recyclability of the catalyst.

Acid-catalyzed olefination of bio-oil in the presence of ethanol

Background: Upgrading of bio-oil using acid-catalyzed olefination with added alcohol was explored. The previous approach of using a reagent such as 1-butanol to overcome the phase separation problem demonstrated excellent results. However, bio-based production of 1-butanol is still a low-yield process. In this work, a low-cost commodity solvent and reagent, ethanol, was used. Also, ethanol has lower viscosity than 1-butanol. Results & discussion: Bio-oil was reacted with excess 1-octene in the presence of solid acid catalysts and ethanol. Acid-catalyzed olefination induced changes in the resulting bio-oil by generating variety of alcohols, ethers, esters and oligomeric mixtures of the starting olefin. The reaction also decreased the water content and acid value, and increased the heating value of the bio-oil. However, the increase of the high heating value of the product bio-oil was moderate due to the presence of two phases in the reaction mixture. Conclusion: Ethanol is not as effective as less-polar 1-butanol at promoting 1-octene and bio-oil phase compatibility. This study shows the need for a low cost, better reagent than ethanol. The reagent should effectively decrease the phase separation to facilitate the reaction between bio-oil and the olefin. Solid acid catalysts with high hydrothermal stability are also needed to improve the upgrading process.

Micellar Electrokinetic Chromatography Method for Determination of the Ten Water-Soluble Vitamins in Food Supplements

The separation and determination of the ten water-soluble vitamins by using capillary electrophoresis in the micellar electrokinetic chromatography in a single run are proposed. The method uses low toxicity and cost solvent (ethanol) as modifier of background electrolyte (BGE) attending to the Green Chemistry principles. The electrophoretic method uses 10.0 % (v/v) ethanol, 2.0 % (w/v) SDS, 0.02 mol L−1 borate at pH 8.70 as BGE. The standard and real sample solutions were injected in the eletrophoretic system by hydrodynamic injection under pressure of 0.80 psi for 8 s, and the separation was carried out in a fused silica capillary under a potential of 28 kV at 25 °C; the analytical signals were monitored at 214 nm. The analytical method is precise (r.s.d. < 6 %), accurate (better than 9 %), selective, sensitive, robust, simple, and presents high analytical frequency as ten water-soluble vitamins were separated in only 18 min, with migration times of 5.75 ± 0.02, 6.81 ± 0.02, 8.13 ± 0.04, 8.80 ± 0.07, 8.98 ± 0.06, 11.10 ± 0.08, 11.34 ± 0.05, 13.85 ± 0.15, 14.82 ± 0.04, and 17.85 ± 0.30 min. Detection and quantification limits of 0.34, 0.32, 0.27, 0.20, 2.50, 4.98, 4.92, 0.30, 0.86 and 0.28 mg L−1 and 1.02, 0.97, 0.83, 0.62, 7.56, 15.09, 14.91, 0.90, 2.59 and 0.83 mg L−1, for vitamins PP (nicotinamide), B12 (cyanocobalamin), B2 (riboflavin), B6 (pyridoxine), B8 (biotin), C (ascorbic acid), B5 (pantothenic acid), B3 (nicotinic acid), B1 (thiamine), and B9 (folic acid), respectively. Excellent recoveries (intra and inter-day) were obtained and, when the method was applied to food supplement analyses the results were in agreement with the conventional HPLC methods.

Engineered CuInSexS2-x Quantum Dots for Sensitized Solar Cells.

Colloidal CuInSexS2-x quantum dots (QDs) are an attractive less-toxic alternative to PbX and CdX (X = S, Se, and Te) QDs for solution-processed semiconductor devices. This relatively new class of QD materials is particularly suited to serving as an absorber in photovoltaics, owing to its high absorption coefficient and near-optimal and finely tunable band gap. Here, we engineer CuInSexS2-x QD sensitizers for enhanced performance of QD-sensitized TiO2 solar cells (QDSSCs). Our QD synthesis employs 1-dodecanethiol (DDT) as a low-cost solvent, which also serves as a ligand, and a sulfur precursor; addition of triakylphosphine selenide leads to incorporation of controlled amounts of selenium, reducing the band gap compared to that of pure CuInS2 QDs. This enables significantly higher photocurrent in the near-infrared (IR) region of the solar spectrum without sacrificing photovoltage. In order to passivate QD surface recombination centers, we perform a surface-cation exchange with Cd prior to sensitization, which enhances chemical stability and leads to a further increase in photocurrent. We use the synthesized QDs to demonstrate proof-of-concept QDSSCs with up to 3.5% power conversion efficiency.