Glycol Solvent Research Articles

Solubility of baclofen in some neat and mixed solvents at different temperatures

Knowledge of drug solubility is crucial and there is no available cosolvency database for baclofen, so far. In the current study, the solubility and density values of baclofen in five mono-solvents (i.e. methanol, ethanol, 1-propanol, 2-propanol and propylene glycol) and the binary mixed solvents of propylene glycol and ethanol within the temperature range of (293.2 –313.2) K are measured using shake-flask method followed by spectroscopy method. The generated data are correlated using some cosolvency models (e.g. the van’t Hoff, CNIBS/Redlich-Kister, the Jouyban-Acree, the Jouyban-Acree-van’t Hoff and λh models). The mean relative deviations for back-calculated solubility data were employed to investigate the accuracy of the models. Moreover, the apparent thermodynamic properties of dissolution of baclofen in the binary non-aqueous mixtures of solvents such as Gibbs free energy, entropy and enthalpy were computed using van't Hoff and Gibbs equations.

Solvometallurgical Process for the Recovery of Tungsten from Scheelite

The industrial state-of-the-art processes to extract tungsten from scheelite (CaWO4) require high pressures and temperatures. These flowsheets consume a large excess of chemicals (which are very hard to recycle) and generate up to 25 tons of high-salinity wastewater per ton of ammonium paratungstate product. In this work, a more sustainable conceptual flowsheet for the recovery of tungsten from high-grade (55.0 wt % W) and medium-grade (3.3 wt % W) scheelite ores was developed at the lab scale. Leaching of CaWO4 was tested in solutions of 37.0 wt % aqueous HCl in organic solvents (ethylene glycol, poly(ethylene glycol) 200, acetonitrile) and ionic liquids (Aliquat 336). The tungstate (HxWyOzn–) generated by the reaction between CaWO4 and HCl was only solubilized in the ethylene glycol system with an appropriate amount of 37.0 wt % aqueous HCl, whereas in all other solvents, it either precipitated or CaWO4 did not dissolve. After the dissolution of tungsten, nonaqueous solvent extraction was used to separate tungsten from calcium, by means of a solvent consisting of 20 vol % Aliquat 336 in the aliphatic diluent GS190 with 10 vol % 1-decanol as a modifier. Scrubbing with water removed the co-extracted iron. Finally, tungsten was recovered as ammonium tungstate (NH4)2WO4, the precursor of ammonium paratungstate, by stripping in a mixture of aqueous ammonia and ammonium chloride. Paratungstate is the most common intermediate for the production of tungsten oxide or tungsten metal. One drawback that needs to be adequately addressed, prior to further upscaling of this conceptual flowsheet, is the potential formation of trace levels of 2-chloroethanol in the leaching stage. It is hypothesized that this problem can be circumvented by further optimizing process conditions to enhance the mass transfer and reduce the reaction time, such as better mixing of the solid and the lixiviant.

Thermodynamic and molecular insights into gas drying with ionic liquid − based mixed absorbents

The suitability of mixed solvents of triethylene glycol (TEG) and ionic liquids (ILs) as gas drying agents was first systematically studied from the phase equilibrium to molecular perspectives. The vapor − liquid equilibrium (VLE) for mixed systems of H2O − TEG, H2O − [EMIM][Tf2N], and H2O − TEG − [EMIM][Tf2N] were experimentally measured and predicted using the UNIFAC-Lei model. The results showed that the UNIFAC-Lei model can be successfully extended to predict VLE from binary to ternary systems. In addition, the vapor pressures of H2O − TEG are lower than those of H2O − [EMIM][Tf2N], while the addition of TEG into H2O − [EMIM][Tf2N] can significantly reduce vapor pressure. Molecular dynamic (MD) simulations demonstrate the relationship between the VLE behaviors and microscopic mechanisms of H2O − TEG − [EMIM][Tf2N] and further validate the suitability of TEG − [EMIM][Tf2N] as desiccants due to hydrogen bond (HB) interactions presented in H2O − TEG, H2O − [EMIM][Tf2N] and TEG − [EMIM][Tf2N]. This study provides theoretical guidance for the application of IL-based mixed absorbents in gas drying processes.

Enhancing bioaccessibility of resveratrol by loading in natural porous starch microparticles

Resveratrol (RSV) is a lipophilic polyphenol susceptible to photo- and thermal degradation, and strategies are to be studied to enable its distribution in food matrices, prevent its degradation during storage, and increase its bioaccessibility during digestion. In this study, the porous matrix of natural starch, in the form of milled freeze-dried potato microparticles (FDPMs), was studied as an absorbent to load RSV. The binary solvent of ethanol and polyethylene glycol 400 (40:60 v/v) was used to dissolve 30% w/v RSV for diffusion into FDPMs. After ethanol was evaporated, the loading capacity was 112 mg RSV/g FDPMs and was maintained at 104 mg RSV/g FDPMs (92.9% retention) after 110-day ambient storage. The RSV stability under UV irradiation at 253 nm was improved by 32% due to shielding effect of FDPMs, and the ferric reducing power was 25% higher than the pristine RSV. The release of RSV in FDPMs was significantly higher than pristine RSV during simulated gastric and intestinal digestions (82.3% vs 51.4% bioaccessibility). The increased reducing power and bioaccessibility were supported by the amorphous state of RSV in FDPMs. The present study illustrates the potential of porous vegetable microparticles as natural matrices to load lipophilic bioactive compounds in functional foods.

Polymer intercalation synthesis of glycoboehmite nanosheets

Novel materials based on the aluminum oxyhydroxide boehmite phase were prepared using a glycothermal reaction in 1,4-butanediol. Under the synthesis conditions, the atomic structure of the boehmite phase is altered by the glycol solvent in place of the interlayer hydroxyl groups, creating glycoboehmite. The structure of glycoboehmite was examined in detail to determine that glycol molecules are intercalated in a bilayer structure, which would suggest that there is twice the expansion identified previously in the literature. This precursor phase enables synthesis of two new phases that incorporate either polyvinylpyrrolidone or hydroxylpropyl cellulose nonionic polymers. These new materials exhibit changes in morphology, thermal properties, and surface chemistry. All the intercalated phases were investigated using PXRD, HRSTEM, SEM, FT-IR, TGA/DSC, zeta potential titrations, and specific surface area measurement. These intercalation polymers are non-ionic and interact through wetting interactions and hydrogen bonding, rather than by chemisorption or chelation with the aluminum ions in the structure.

Flexible organohydrogel ionic skin with Ultra-Low temperature freezing resistance and Ultra-Durable moisture retention

HypothesisOne prevailing method to construct excellent temperature tolerance/long-lasting moisture hydrogels is to couple the original hydrogel networks with freezing-tolerant/moisture retaining agents, including ionic liquids, inorganic salts, zwitterionic osmolytes, and polyhydric alcohols. Among them, organohydrogels have shed new light on the development of ionic skins with long-term usability and stable sensing performance at subzero temperatures due to their long-lasting water retention and anti-freezing capability. ExperimentsWe report a dual network organohydrogel by doping conductive ZnSO4 into the double network hydrogel of polyvinyl alcohol-polyacrylamide (PVA-PAM) with subsequent immersing in a mixed solvent of ethylene glycol (EG) and H2O. The anti-freezing and moisture retaining abilities of the PVA/PAM/Zn/EG (PPZE) organohydrogel were studied and the sensing performances of the PPZE organohydrogel-based ionic skin were investigated. FindingsThe organohydrogel exhibits a high conductivity (0.44 S m−1), excellent fatigue resistance and exceptional moisture retaining ability with more than 99.3% of the initial weight retention after 31 days storage at ambient temperature. Importantly, the PPZE organohydrogel-based ionic skin shows an ultra-low temperature anti-freezing ability and remains flexibility and sensing capability with a high sensitivity (signal response time ∼ 0.23 s) even at -50 °C. The PPZE organohydrogel demonstrates a tremendous potential in artificial skin and health monitoring.

Influence of Solvents on Properties of ZnS Thin Films Synthesized by Chemical Spray Pyrolysis Technique

Abstract: In this paper, the influence of solvents on the structural, optical, surface and electrical properties of spray-deposited ZnS thin films has been studied. Different precursor mixtures were prepared from ethylene glycol, deionized water and alcohol solvents and sprayed on heated glasses via a simple and cost-effective technique known as spray pyrolysis. XRD patterns confirmed cubic and tetragonal phases of synthesized ZnS material. The optical analysis of the synthesized ZnS films showed that films prepared using ethylene glycol solvent have the highest transmittance and the best bandgap (3.61 eV). Surface morphology showed the absence of voids and pinholes in the Scanning Electron Micrograph of ZnS film prepared from ethylene glycol and electrical studies showed that ZnS films prepared using the same solvent have the lowest resistivity. Keywords: ZnS, Thin film, Spray pyrolysis, Bandgap, Morphology.

Impact of Solvent type on the Structural, Surface morphology and Optical energy gap of Kesterite Cu2ZnSnS4 thin films deposited by solvothermal method

In present work kesterite quaternary Cu2ZnSnS4 (CZTS) semiconductor thin films were prepared on fluorine-doped tin oxide (FTO) substrate by solvothermal method using different solvent types Ethylene glycol (EG), polyethylene glycol (PEG), and Ethylenediamine (ED). Crystal structure, surface morphology and optical characteristics of the prepared thin film were characterized by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and UV–Vis absorption spectroscopies. X-ray diffraction results reveal that the deposited films have polycrystalline nature and in a kesterite phase (tetragonal structure). the crystallite size is in the rang (20-27) nm and the largest one is for the prepared by using PEG solvent. The films surface morphology shows smooth and uniform surface with well distributed spherical particles with largest particles for the films deposited by EG solvent. The EDS spectra confirmed the the existence of the elements Cu, Zn, Sn and S of the films composition. The direct optical energy gap shows different values caused by using different solvent type, where the lower band gap is about 1.56 eV and the largest is about 1.9 eV for the films using ED and EG respectively.

Effect of dispersing solvents for ionomers on the performance and durability of catalyst layers in proton exchange membrane fuel cells

The microstructure of catalyst layers (CLs) plays a crucial role in determining the performance and durability of membrane electrode assemblies (MEAs) in proton exchange membrane fuel cells (PEMFCs). The microstructure substantially influences electrochemical reactions occurring at CLs due to the effect of triple-phase boundary formed by the physicochemical interaction of electrocatalyst, ionomer binder, and dispersing solvent. In catalyst inks comprising of the aforementioned three main components, dispersing solvents could be a key parameter for the formation of the optimal microstructure. In this study, the effect of the solvents in ionomer dispersions on the performance and durability of CLs for PEMFCs is investigated. Commercially available (water based) and laboratory-made (glycol based) ionomer dispersions are used. As a result, the physicochemical and electrochemical evaluation of the MEAs using glycol solvent based ionomer dispersions shows the thinner ionomer layer surrounding electrocatalyst and the crack-free surface of CLs, compared with that of the MEA using water based ionomer dispersion as expected. Among the MEAs using various glycol solvent based ionomer dispersions, ethylene glycol based ionomer dispersion results in the highest mobility of the main chain of ionomer in the corresponding solvent and the highest performance and durability for PEMFCs due to the lowest viscosity. This study provides useful knowledge in the selection of dispersing solvents for CLs with enhanced performance and durability in PEMFCs.

Effects of electrodeposition parameters on corrosion resistance of ZnSn coatings on carbon steel obtained from eutectic mixture based on choline chloride and ethylene glycol

Zn and ZnSn coatings were electrodeposited on carbon steel surfaces from choline chloride and ethylene glycol solvent (1ChCl:2EG). The corrosion resistance of the coatings was investigated in a 3.5% NaCl solution, and the results revealed that Zn deposition was favored by increasing bath temperature and electrodeposition potential. Besides, Zn-enriched coatings were also obtained from Sn-rich Zn/Sn baths, and the coating morphologies were affected by these parameters. Finally, the ZnSn layer (14% Sn) electrodeposited at −1.3 V and 363 K increased the corrosion resistance up to 6 times towards the pure Zn layer under the same conditions.

Fabrication of Magnetic Ink Chromium Ferrite Using Iron Sand

In this research iron sand was used as raw material for fabrication of magnetic ink of chromium ferrite. The first step of research was synthesizing iron sand into pigment of chromium ferrite using powder metallurgy method. The second step was processing pigment into magnetic ink. The ink was produced by mixture pigment into binder solution of polyvinyl alcohol and heated. While stirring the mixture was added alcohol as a solvent and additives of polyethylene glycol, propylene glycol, and glycerine by certain composition. The variation of pigment mass was 6 g, 8 g, 10 g, 12 g, 14 g, and 14 g. The produced ink was characterized its properties, those were structure using XRD method, colour, density, viscosity, organoleptic, CCD microscope, and magnetic susceptibility. Using XRD was found that the pigment have a structure of CrO.Fe2O3 with size of 84.81nm. The colour of ink was dark green. The brightness of the ink decreases with increasing pigment mass. The coordinates values of a* and b* was fluctuated. The ink viscosity was around 7.64 cP until 19.59 cP, the density was around 0.954 gr/cm3 until 1.007 gr/cm3. By organoleptic study was found that the ink can be used on the whiteboard. From CCD microscope was known that distribution of ink more evenly white increasing of pigment mass. The value of magnetic susceptibility was around of 1.500175×10−5 m3/kg until 1.504662×10−5 m3/kg.

Carbon-free Cu/SbxOy/Sb nanocomposites with yolk-shell and hollow structures as high-performance anodes for lithium-ion storage

We report a simple approach for synthesizing Cu/SbxOy/Sb nanocomposite materials possessing yolk-shell structures for use as novel anode materials for Li-ion batteries. The nanocomposites were synthesized by a galvanic replacement reaction between Cu2+ ions and Sb in triethylene glycol solvent at a desired temperature. The properties including morphology, composition, and structure of the as-prepared nanocomposites were investigated using advanced characterization techniques, from which yolk-shell structures with a uniform size and morphology were observed, whereas some unconsumed Sb on the outside of the yolk was covered by the shell. The Cu/SbxOy/Sb nanocomposites presented high specific capacity, good cycling stability, and rate performance, resulting in a synergistic effect between the unique nanostructures of the composites and the inactive Cu material, which promotes stabilization of the electrode structure and enhances the kinetics of the electrochemical reaction. Specifically, the Cu/SbxOy/Sb-0.5h yolk–shell electrode delivered a reversible capacity of 563mAhg1 at the 150th cycle at 100 mA g1, with a notable rate capability. Therefore, the as-prepared nanocomposites are considered promising candidates as anode materials for Li-ion cells.

Binary Solvent Systems for Piezoelectric Printing Crack-Free PAM/ZrOx Hybrid Thin Films through Nanostructure Modulation.

Polymer/oxide hybrid thin films, which have excellent electrical and mechanical performance, can be effectively fabricated through the sol-gel process, showing great potential in the future printed electronics. However, gelation of polymer/oxide ink systems can easily occur during a thermal process in which case capillary stress can lead to the crack of printed films due to the long period of stress accumulation. To solve this problem, the effect of different solvent systems on formed PAM/ZrOx hybrid films, which were printed by piezoelectric printing, was studied in this paper, including single solvent systems of glycol and binary solvent systems of glycol and water. The result showed that the microstructure characteristics and mechanical properties of hybrid nanostructures formed in different solvent systems varied significantly, and crack behavior can be regulated by simply adjusting the water volume ratio of the solvent system. The crack formation was significantly inhibited when the water volume ratio reached 25%.

Development of morphology tuned SnS hierarchical structures for enhanced photosensitive photodiode fabrication

Hierarchical structure transformation and surface modification of solvothermal method synthesized SnS with oleic acid in ethylene glycol solvent were discussed in detail. The structural, optical, and morphology of as prepared SnS samples were examined by X-ray diffraction (XRD), Raman Spectroscopy, and Field Emission Scanning Electron Microscopy (FE-SEM). XRD verifies the orthorhombic crystal structure of the SnS phase for all synthesized samples. Single-phase nature of synthesized particles was confirmed with Raman characterization. Morphology evolution of SnS from regular to hierarchical structures upon adding oleic acid is performed through FE-SEM analysis. Junction diodes p-SnS/n-Si fabricated with different oleic acid concentrations (0.5, 1.5, and 2.5 mL) synthesized SnS particles show better photo-response, which can be used in photodiode applications.

Optimization and eco-efficiency analysis of extractive distillation processes with different solvents for separating the ternary mixture embedding two azeotropes

The selection of feasible solvent is of great significance for separating azeotropes via extractive distillation since various solvents can cause different product orders, flowsheet structures, and eco-efficiencies of extractive distillation processes. Limited efforts are focused on the effect of various solvents on the separation of ternary mixtures embedding two azeotropes, especially for the design of the extractive dividing-wall column separation configurations. To fill the research gap, the separation of azeotropic mixtures embedding two azeotropes is investigated using extractive distillation method with various solvents through taking the methyl acetate/ethyl acetate/methanol mixture as an example. First, the theoretical thermodynamic feasibility of four solvents including ethylene glycol, dimethyl sulfoxide, chlorobenzene, and aniline is explored. The individual light-heavy component orders are determined through the thermodynamic insights including the construction of the pseudo binary vapor–liquid phase equilibrium diagrams and overall phase diagrams with residue curves and iso-volatility curves after adding solvents, while are further verified using σ-profiles from microscopic mechanism. Second, the conceptual design of the extractive distillation flowsheets including conventional extractive distillation and extractive dividing-wall column separation configurations with individual solvents is performed. The effects of various solvents on the flowsheet structures and product orders are analyzed. Afterwards, the extractive distillation flowsheets are simulated and optimized economically to minimize the total annual costs through the genetic algorithm, except for the solvent ethylene glycol due to the unfeasibility of realistic simulation. The eco-efficiency analysis is performed via quantifying the Eco-Indicator 99 and thermodynamic performances as well as economic costs. The results indicate that the extractive distillation processes with dimethyl sulfoxide or chlorobenzene as solvent can show a certain degree of advantage compared with that using aniline as solvent in terms of eco-efficiency. The optimal separation configuration is the extractive dividing-wall column containing two dividing-walls with CB as solvent, and its Eco-efficiency Comparison Index increased to 80.54% compared to the worst scheme that is the extractive dividing-wall column containing one dividing-wall with AN as solvent.

Impact of Catalyst Ink Dispersing Solvent on PEM Fuel Cell Performance and Durability

The dispersing solvent used for fuel cell catalyst ink preparation plays a vital role in establishing the resulting morphology of the electrode layers, which in turn will impact the performance of proton exchange membrane (PEM) fuel cells. In this study, we report the impact of various ionomer dispersion solvents on PEM fuel cell performance and durability; two aqueous (1-propanol/water and 2-propanol/water) and several non-aqueous dispersing solvents (ethylene glycol and 1,2-butanediol) are compared. The cathode catalyst layer (CCL) fabricated using inks prepared with 1-propanol/water (3:1, w/w) exhibited the best initial performance followed by the CCL prepared using ethylene glycol. The CCLs made from non-aqueous ethylene glycol and 1,2-butanediol exhibited the best durability upon accelerated stress testing. Scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy indicated that, after the stress test, the distribution of both the Nafion ionomer and Pt nanoparticles within the CCLs prepared with non-aqueous ionomer dispersions underwent less change than those prepared with aqueous dispersions, which is responsible for the improved durability.

Leidenfrost Method for Synthesis of BiFeO3 and the Effect of Solvent Variation on its Optical Properties and Morphology

Background: Nanotechnology has wide applications in various fields of life. To synthesis nanoparticles, many different methods have been used. Although these methods form nanoparticles with different morphologies and properties, it needs expensive tools, multi-steps, various chemicals and yields toxic by-products. The trend today is to use green synthesis with one step self assembly methods and eco-friendly one. Objective: In this manuscript, high pure BiFeO3 (BFO) multiferroic perovskite was prepared using the green chemical Leidenfrost technique as a cost-effective and eco-friendly method. Methods: Two different solvents (viz, water and ethylene glycol) were used for the synthesis of BiFeO3 nanoparticles. The resulting nanopowder was characterized by XRD, SEM, FTIR and Uvisible spectrometric techniques. Results: The XRD results show that BiFeO3 was developed in a pure phase in the case of water solvent, whereas one peak of a Bi2O3 phase was observed in the case of ethylene glycol solvent. The crystallite size was determined using the Scherrer equation to be 36.58 and 61.02 nm for aqueous and non-aqueous solvents, respectively (viz, water and ethylene glycol). The optical band gap was determined using the Kubelka-Munk function, which appears a blue shift from 2.08 eV for ethylene glycol to 1.80 eV for aqueous solvent. Conclusion: Leidenfrost method proves its efficiency for the synthesis BFO nanoparticles with low cost and simple steps. The high dependence of the purity and optical properties on the solvent variation was perceived.

Eco-Friendly Synthesis and Applicability to Silver Ink of Silver Nanoparticles Prepared via Stepwise-Modified Tollens Method.

Silver nanoparticles were eco-friendly synthesized at room temperature via a Tollens process modified with the stepwise method using eco-friendly precursors (citric acid and acetic acid). The field emission scanning electron spectroscopy was used to study the morphology of silver nanoparticles. The mean size of silver nanoparticles and the components of products were theoretically determined using UV-Vis and X-ray Diffraction spectra. The mole ratio between the silver ion, citric acid and the buffer acid solution (acetic acid) strongly influences the mean size and the composition of the product. The appearance of acetic acid in the buffer acid solution helped increase the efficiency of silver nanoparticles preparation. With the mole ratio n[Ag+]:ncitric:nacetic = 1.0:2.5:2.5, the highest preparation efficiency was obtained, the silver nanoparticles had an average dimension of ˜11 nm and narrow size distribution. The silver nanoparticles were dispersed into different solvents to examine their applicability to silver ink. The silver ink using propylene glycol solvent showed good applicability to silver ink which could work at room temperature.

The Enhancement of Selectivity and Activity for Two-Electron Oxygen Reduction Reaction by Tuned Oxygen Defects on Amorphous Hydroxide Catalysts

Amorphous catalysts, thanks to their unique coordinately unsaturated properties and abundant of defect sites, incline to possess higher activity and selectivity than their crystalline counterparts....

Simulation of ethanol recovery and economic analysis of pectin production on an industrial scale.

Taking into account that the industrial processing of passion fruit generates significant amounts of waste (only the peels represent 51% of the total mass of the fruit), in the present study an economic analysis was conducted to evaluate industrial line viability for pectin extraction from passion fruit peels. Knowing that absolute ethanol (99.50% purity), used in the precipitation and washing steps, has a higher cost, a simulation of extractive distillation was performed using solvents ethylene glycol and glycerol, in the software Aspen Plus v.11, being possible to recover 99.63% of ethanol for both solvents. The results of the economic evaluation showed that the process using ethylene glycol has an advantage, mainly due to its higher profitability (1.13 times higher), lower production cost (94.86% of the price using glycerol), and a lower breakeven point (around 3% smaller). The financial indicators showed profitability and attractiveness for the implementation of this processing line.