Ethanol-water Solvent Research Articles

Solubility of 4-Chloro-2,5-dimethoxynitrobenzene, 4-Chloro-2,5-dimethoxyaniline, and 2,5-Dimethoxyaniline in Binary and Pure Solvents: Determination and Modeling

Using the dynamic method over the temperature range of (277 to 340) K at atmosphere pressure, solubility of 4-chloro-2,5-dimethoxynitrobenzene (CDMB) and 4-chloro-2,5-dimethoxyaniline (CDMA) in methanol–water and ethanol–water solvent mixtures, where solute-free mass fraction of methanol and ethanol range from 0.2 to 0.8, and solubility of CDMB, CDMA, and 2,5-dimethoxyaniline (DMAn) in 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, and diethylene glycol have been investigated. In all solvents, there exists a direct relationship between solubility and temperature. In mixture solvents, the experimental data are correlated using the Wilson and the NRTL models. The solubility of CDMB and CDMA increases with the added amount of methanol or ethanol. In pure organic solvents, significant differences are discerned for the solubility of CDMB, CDMA, and DMAn, and data are correlated with the Wilson, the NRTL, the modified Apelblat, and the λh models. The solubility of DMAn is strongly dependent on tempera...

Artificial Neural Network and Multiple Linear Regression for Prediction and Classification of Sustainability of Sodium and Potassium Coronates

Models of multiple linear regression and multilayer artificial neural network have been developed for modeling and predicting the stability constants of sodium and potassium coronates basing on the properties of aqueous-organic solvents (water-methanol, water-propan-2-ol, water-acetonitrile, and water-acetone). The values of the coronates stability constants in water-ethanol solvents have been predicted, and the predictions of the models of multiple linear regression and an artificial neural network models have been compared. The contributions of electrostatic, cohesive, and electron-donating interactions to the increase in the stability of the coronates have been quantitatively assessed basing on the models of multiple linear regression and the principle of free energies linearity. Neural network models based on unsupervised (multilayer perceptrons) and supervised (Kohonen networks) learning algorithms have been developed to classify the stability of sodium and potassium coronates. The neural network classifiers have fully confirmed the classification of the coronated stability via the k-means exploration method.

Pulp Fibroblast Cell Apoptosis After Application of Hema Dentine Bonding Material with Ethanol and Water Solvent

The most common main materials for dentin bonding for composite resin restoration is 2-hydroxyethyl methacrylate (HEMA). HEMA has beneficial physical and chemical properties, and stable, yet toxic. The addition of ethanol or water, may reduce the toxic effect of HEMA. Ethanol solvent has lower H-bonding capacity compared to water solvent, so it can bind less free radicals from the residual monomer. This study aimed to analyze apoptosis due to dentine bonding application with ethanol and water solvent. Fibroblast culture cells were obtained from extracted third molar, by means of tripsinasion method. The cells were divided into 4 groups as reached confluent: cell culture without treatment as control, cell culture with scaffold chitosan, cell culture with scaffold and polymerized dentin bonding with ethanol or water solvent. Apoptosis observation was conducted using immunohistochemistry method with ethidium bromide acridin orange staining, under fluorescent microscope with 40´ magnification. There was a significant difference among groups (p=0.0001), yet no differences found between different solvent. Apoptosis rate in fibroblast cells culture exposed to HEMA bonding with ethanol solvent was 67%, while the cells exposed to HEMA bonding with water solvent was 44%. The effect of dentin bonding with ethanol solvent and water solvent towards apoptosis rate of pulp fibroblast cells is not different.

Pd-containing Mono- and Bimetallic Nanoparticles Incorporated in Highly Porous Hypercrosslinked Polystyrene as Effective Catalysts of Suzuki Cross-coupling

This paper describes synthesis of Pd-containing catalysts of Suzuki cross-coupling based on non-functionalized hyper-crosslinked polystyrene (HPS) at variation of Pd precursor nature (PdCl2, PdCl2(CH3CN)2 or PdCl2(PhCN)2). Relatively low affinity of Pd species to the chosen polymeric support was shown to be responsible for in situ formation of Pd nanoparticles and their aggregates. During the investigation of aryl halide nature, catalytic activity was shown to decrease in the following order: Br > I > Cl. Best results were obtained for the preliminarily reduced HPS-based sample synthesized while using PdCl2 in the reaction between phenylboronic acid and 4-bromoanisole: more than 93% yield of cross-coupling product was achieved at mild reaction conditions (NaOH, 60oC, solvent ethanol-water mixture) using 0.8 mol.% of Pd.

Investigation on solvolysis liquefaction mechanism of Chlorella pyrenoidosa in ethanol–water solvent based on major model compounds: Protein and starch

This work explored the liquefaction mechanism of Chlorella pyrenoidosa in ethanol−water solvent. Model compounds (soya protein and corn starch) were liquefied in water, ethanol and ethanol−water solvents to investigate the synergistic effect between ethanol and water on the biocrude oil yield. To reveal the cross-interaction between protein and starch, the effect of different mixed ratios on biocrude oil yield was studied. The protein/carbohydrate ratio of feedstock was adjusted by mixing starch with microalgae to reveal the effect of Maillard reaction on the yield and quality of biocrude oil. The results showed that ethanol–water solvent contributed better to the decomposition of protein and starch compared with pure water and ethanol. The ratios of protein/starch at 2/1 and microalgae/starch at 100/14 achieved the highest biocrude oil yield and energy recovery. Based on chemical compositions of biocrude oil and light oil, a possible reaction pathway of solvolysis liquefaction of microalgae in ethanol–water solvent was proposed.

Solvent Effects on Nafion Dispersion Structure Probed By Infrared Spectroscopy

The structure of Nafion dispersed in water and ethanol solutions was investigated using infrared spectroscopy. Since the properties of dispersing fluids can affect the mechanical strength of solution-cast Nafion thin films,1 it was of interest to gain insights into the structure and the vibrational spectral properties of the ionomer in the dispersion phase. To minimize deleterious effects of optical dispersion,2 traditional transmission infrared spectra were recorded from both dispersions as well as solvent-free thin films. Subsequently, transitions from the dispersion, through the gel-phase and dried film were followed as a function of time during film formation using the attenuated total reflection (ATR) infrared sampling technique. The vibrational spectra of thin Nafion films prepared from dispersions in ethanol solvent and water solvent were similar, except the former had a pronounced shoulder near 1125 cm-1 and sharper 983 cm-1 peak, both of which can be ascribed to sidechain vibrations. The enrichment of trace water in the ethanol solvent during evaporative drying was quantified through analysis of the 2750 cm-1 – 3500 cm-1 spectral region using partial least square (PLS) modeling. In the gel-phase, water was detected above 50 mol%, indicating water enrichment should be considered in developing models for solvent effects on Nafion film formation. Kim, Y. S.; Welch, C. F.; Hjelm, R. P.; Mack, N. H.; Labouriau, A.; Orler, E. B. Origin of toughness in dispersion-cast Nafion membranes Macromolecules 2015, 48, 2161-2172.Kollath, V. O.; Liang, Y.; Mayer, F. D.; Ma, X.; Korzeniewski, C.; Karan, K. Model-based analyses of confined polymer electrolyte nanothin films experimentally probed by polarized ATR−FTIR spectroscopy J. Phys. Chem. C 2018, 122, 9578−9585. Figure 1

Chiral Discrimination By Porphyrin Supramolecular Aggregates Based Chemical Sensors

The study of the formation of porphyrin aggregates characterized by supramolecular chirality is an important issue amenable to wide applications. One approach to prepare these architectures takes advantage by the presence of chiral substituents on the periphery of the macrocycles acting as specific chiral effectors during the molecular recognition event. We have exploited a tetraphenylporphyrin bearing a peripheral proline group in ethanol–water solvent mixtures (Figure 1 a); the aggregation led to the formation of extended J-type aggregates, featuring supramolecular chirality. The aggregates have been grafted onto ZnO nanoparticles and then QMB sensor surfaces have been coated with a thick film of such hybrid materials. Sensing properties of such hybrid materials have been extensively studied and results show that they have promising features for the development of reliable and efficient sensors based on the implementation of large chiral surfaces. Figure 1

Characterization of dye cells for a high-repetition-rate pulsed dye laser by particle image velocimetry (PIV)

Two types of converging–straight–diverging dye cells have been fabricated for validating computational results. The evolution of velocity profiles along the flow direction in the dye cell has been obtained using the computational fluid dynamics model as well as particle image velocimetry (PIV). The computational results are qualitatively compared with the results obtained from the PIV technique. The two-dimensional velocity profiles along the flow direction as well as perpendicular to it have been obtained using PIV. The flow characteristic of the dye cells is studied with commonly used dye solvents and the onset of cavitation in the diverging section of the dye cell has been observed. The flow characteristic of the dye cell is an important parameter for selecting the appropriate dye flow system for dye lasers, so that the obligatory flow velocities could be achieved for high-repetition-rate pulsed operation. The dye cell was tested with a grazing-incidence grating cavity pumped by a 9 kHz copper vapour laser. The effect of a binary solvent on the tuning range and conversion efficiency of the dye laser has been studied. The redshift in the peak wavelength of the sulforhodamine 101 (SRh101) dye laser with the binary solvent of ethanol and de-mineralised water was obtained.

Synthesis of Dihydropyridine Derivatives under Eco‐friendly Approach and Investigation of Cytotoxic Activity

In an effort for development of innovative biologically active agents, a sequence of 1,4‐dihydropyridine analogues was synthesized through the green synthetic method. In addition, all compounds were evaluated for their cytotoxic activities against three human cancer cell lines and mouse melanoma and figured out the most active compounds. Besides, promoter reusability, easy handling of the chemical reagent, simple reaction process, time minimization, ethanol–water solvent compatibility, and cost reduction reagent are key tools for this fruitful path. Thus, these examinations recommended that dihydropyridine and their derivatives are motivating moieties for the discovery of new anticancer drugs.

Optimization of garlic oil extraction via batch microwave- assisted hydrodistillation

The batch microwave-assisted hydrodistillation (MAHD) process has become a popular green extraction technique to extract essential oils from natural plants. The traditional hydrodistillation process is less efficient than the MAHD as the former often requires longer extraction period and higher energy consumption. This paper reports an optimization study of the batch MAHD process coupled with ethanol-water solvent in extracting garlic oil. A fundamental model of the batch MAHD process is used to simulate the extraction yield under various input conditions. The result of the model-based optimization is compared with the result from an experimental-based optimization. The objectives of the optimization are to maximize the extraction yield while simultaneously minimizing the extraction period and total energy consumption. This optimization results in the extraction efficiency and productivity equal to 90.44 μg/kJ and 3,254 μg/minute of garlic oil respectively.

Hydrolysis of mechanically pre-treated cellulose catalyzed by solid acid SO42−-TiO2 in water–ethanol solvent

Abstract An efficient catalyst SO42−-TiO2 (ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 °C (ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 °C for 30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Bronsted acid sites ratio for ST-450 induced by bidentate ligands between SO42− and TiO2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm3·g−1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 °C exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO42− and TiO2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.

Thermodynamics of complex formation between hydroxypropyl-β-cyclodextrin and quercetin in water–ethanol solvents at T = 298.15 K

Quercetin (QCT) is a flavonoid possessing many activities, such as neuro-/cardioprotective, anti-inflammatory and anticancer, but its pharmacological application is severely curtailed by its low water solubility and in vivo bioavailability. The formation of a QCT–hydroxypropyl-β-cyclodextrin (HPβCD) host–guest complex is promising to improve QCT therapeutic potential. Therefore, here the heat effects of HPβCD solutions with QCT solutions in water–ethanol solvents at different concentrations were studied by calorimetric titration, and the stability of molecular complexes was assessed by UV–Vis spectrophotometry. Calorimetric titrations revealed the formation of a QCT/HPβCD host–guest complex with a stoichiometric ratio of 1:1 in X(EtOH) = 0.00, 0.05 and 0.10 molar fractions of solvents at pH = 7.0 and pH = 8.1. Thermodynamic parameters of the complex formation reaction (lgK; ΔrH; TΔrS) were obtained in these experimental conditions. Differently, no complex formation was noticed in water–ethanol mixed solvent when ethanol volume fraction exceeded 0.2 at neutral and alkaline pH, as well as a volume fraction higher than 0.1 at acidic pH. Furthermore, the results of differential scanning calorimetry tests run on dried HPβCD after dissolution in hydroalcoholic solutions indicated that ethanol and water compete for the complexation within the hydrophobic cavity of HPβCD. This explains the decreased QCT complexation efficacy in the presence of ethanol beyond 0.1 or 0.2 volume fraction.

Effect of Temperature on Annealing Products of Synthesized Opal Matrices

In this paper, we describe the synthesis of opal matrices by the sol-gel method and the α-cristobalite production from them by high-temperature annealing. Both the conditions for preparing synthetic opal matrices by the hydrolysis of tetraethoxysilane in a binary ethanol-water solvent using an ammonia solution as a catalyst and the reagent concentrations for this process are described in detail. The silica particles were prepared by multistage growth to the required size at addition of tetraethoxysilane to the reaction mixture. A temperature regime for drying the siliceous xerogel with the production of porous matrices for further use and annealing to obtain high-purity α-cristobalite is proposed. Structural adjustments, such as an increase in the matrix density, their hardening, and a temperature-dependent change in the matrix porosity, are described. Open-pore matrices consisting of amorphous silicon dioxide are prepared by annealing up to 1100°C. The prepared matrices can later be used for their impregnation with various compositions to obtain various types of sensors, composite materials, and inverted matrices. The transition of a silica xerogel from an amorphous state to a crystalline state with the formation of low-temperature α-cristobalite with an α-tridymite admixture by drying and annealing at 1300°C is shown. Further annealing at 1650°C leads to the formation of a transparent nonporous sample of α-cristobalite. All processes were performed under the control of scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis.

Surface engineering of CdTe quantum dots using ethanol as a co-solvent for enhanced current conversion efficiency in QDSSC

Achieving a cost-effective synthesis of QDs with superior surface quality will dictate the feasibility of quantum dots in commercial photovoltaic devices. Here we report a simple aqueous synthesis of CdTe quantum dots coated with thin CdS layer in water-ethanol solvent mixture for better surface eminence. Enhanced solubility of capping agent and slow growth rate of CdS over CdTe taking place in water ethanol solvent mixture leads to strain free interface construction resulting in 51% enhancement of Photo Luminescence Quantum Yield. Controlling the solubility and growth rate of CdS coating over CdTe core QDs via ethanol addition exhibits a 28.4% and 44.6% improvement in short circuit current densities and quantum dot sensitized solar cells with a conversion efficiency of 2.5% is achieved. Our results show that mixed solvents can be utilized for optimizing the aqueous synthesis of CdTe/CdS QDs with enhanced optical properties leading to better performing photovoltaic devices.

Determination of the solubility of 2-Methyl-1,3-benzothiazol-5-amine molecule with aqueous ethanol by NMR spectroscopy

Herein, solubility of 2-Methyl-1,3-benzothiazol-5-amine molecule is studied at different alcohol concentrations and at different temperatures in water-ethanol solvents using NMR spectroscopy. The hydrogen bonds between title molecule and solvent molecules, bond lengths, energy values and 13C, 15N NMR chemical shifts of the title molecule were calculated using B3LYP/6-311++G(d,p) basis set. In addition, experimental results are supported by theoretical results. Alcohol concentrations and different temperatures dramatically affected 15N NMR spectra. At low concentrations and different temperatures more shift toward higher magnetic area region were observed in the 15N NMR chemical shift values of the nitrogen atom (N15). In addition, this shift affects the carbon atoms neighbor to nitrogen atom as well as the nitrogen atom itself, thereby causing the chemical shift values of these atoms to change. This is because of the hydrogen bonds between nitrogen atom of title molecule and ethanol and water molecules. It has also been observed that the number of hydrogen bonds remains constant in higher solvent concentration values.

Enthalpies of Glycine Protonation in Water–Acetone and Water–Ethanol Solvents

Heat effects of the reaction of glycine protonation at 298 K in water–ethanol (µ = 0.1 (NaClO4)) and water–acetone (µ = 0.3 (NaClO4)) solvents of various compositions are determined via calorimetry. The enthalpies of the resolvation of glycinium ions in aqueous solutions of ethanol and acetone are calculated using the literature data. It is established that a minor change in the heat effect of the reaction of glycine protonation in water–ethanol and water–acetone solvents is associated with the mutual compensation of the enthalpies of proton, glycinium-ion, and glycine resolvation in these media. It is shown that the contribution from the enthalpy component to the change in the Gibbs energy of this reaction is insignificant.

Understanding the Roles of Oiling-out on Crystallization of β-Alanine: Unusual Behavior in Metastable Zone Width and Surface Nucleation during Growth Stage

Oiling-out crystallization of β-alanine was conducted in water–ethanol solvent mixtures, and the roles of oiling-out on the crystallization of β-alanine were investigated during the crystal nucleation and growth stages, respectively. Nucleation metastable zone width broadened with an increase of saturation temperature when oiling-out occurred, contrary to that observed in absence of oiling-out. This observed phenomenon could be explained by the solvent composition change in the nucleation phase (dense oil droplets) under different temperatures. In the crystal growth stage, the size of oil droplets could be controlled by varying agitation speeds. The resulting crystals were lumpy with bulges on specific surfaces when the agitation speed exceeded a certain level. It was supposed to be that the absorption of oil droplets on the crystal surfaces during growth stage led to the surface nucleation, and then the bulges formed consequently. Such performance was never revealed in normal single-phase crystallization...

Recovery of polyphenols onto porous carbons developed from exhausted grape pomace: A sustainable approach for the treatment of wine wastewaters

Removal of total polyphenols (TPP) is not only necessary as a pretreatment stepfor anaerobic digestion of wine wastewaters (WWW) but also the recovered polyphenols can be used as a dietary supplement. With a view to make the process sustainable, eco-efficient and cost effective, exhausted grape pomace (EGP) after the extraction of polyphenols was impregnated with ZnCl2 (1:1.5) and further activated at 450 °C for 1 h under inert atmosphere. The GPAC (grape pomace activated carbon) thus developed exhibited well-developed porosity with a predominance of micropores, high surface area and selective surface binding sites. Batch adsorption conducted on diluted WWW revealed the better performance of GPAC (84.3% removal) as compared to EGP (48.5% removal) under similar conditions; with maximum adsorption taking place at pH 3.8. While pH studies indicated a possible electron-donor-acceptor mechanism in the binding of TPP, kinetic studies indicated that diffusion was mediated by the porosity in GPAC. Isotherm studies conducted on GPAC and commercial carbon (CAC) revealed multilayer binding under WWW while Langmuir model was operative under simulated conditions. Contrary to the better performance of CAC, the same for GPAC was comparable at higher dosage where >80%TPP was removed from undiluted WWW. The phenol adsorption capacity of GPAC from real (28.4 mg/g) and from simulated wastewater (142.6 mg/g) was higher as compared to other reported adsorbents. Desorption of TPP from loaded GPAC was maximum (∼91%) with 1:1 ethanol-water solvent. The results reveal a sustainable eco-friendly solution for valorisation of exhausted grape pomace for recovery of polyphenols from wine wastewater.

Cosolvent Selection for Supercritical Fluid Extraction (Sfe) of Bioactive Compounds from Orthosiphon stamineus

In this work, a preliminary study was conducted to study the effects of different types and concentrations of cosolvents based on the total yield and antioxidants capacity prior to supercritical fluid extraction (SFE) of Orthosiphon stamineus (locally referred as misai kucing). Initially, a comparison was made by cold maceration technique with nine types of different cosolvents, namely water, pure ethanol, 25% (v/v) of ethanol in water, 50% (v/v) of ethanol in water, 75% (v/v) of ethanol in water, pure methanol, 25% (v/v) of methanol in water, 50% (v/v) of methanol in water and 75% (v/v) of methanol in water. The antioxidant capacity was analysed by free radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), total phenolic content (TPC) and total flavonoid content (TFC). Aqueous ethanolic solvent of 50% (v/v) ethanol in water showed the highest total yield of extract of 4.64 ± 0.02%. All antioxidant assays of TPC and TFC showed the highest value of 3.42 ± 0.08 mg GAE g−1 extract, 4.7 ± 0.14 mg CAE g−1 extract, respectively and IC50 value for DPPH was 0.625 μg/mL for 50% (v/v) ethanol in water extract. Based on the overall result, ethanolic solvents gave a better result for all antioxidant assays compared to those of methanolic solvents. Using the selected cosolvent, the identification of target compounds, which were rosmarinic acid, eupatorin and sinensetin from supercritical fluid extraction was determined by using HPLC. In conclusion, ethanol-water solvent was efficient in extracting bioactive compounds in O. stamineus and also improved the total yield, thus the usage of ethanolic solvent in different concentrations should be considered for further optimisation of SFE with cosolvent studies.

Catalytic co-liquefaction of lignin and lignite coal for aromatic liquid fuels and chemicals in mixed solvent of ethanol-water in the presence of a hematite ore

In this work, a raw hematite ore (Fe2O3) displayed to be a low-cost but effective catalyst for co-liquefaction of hydrolysis lignin (HL) and Xilinguole lignite (XL) in ethanol-water (50:50, v/v) mixed solvent under initial N2 atmosphere to produce heavy oil (HO) as a potential source of liquid fuel and aromatic chemicals. The liquefaction of HL and XL separately without catalyst resulted in a maximum of approx. 18 and 11 wt% yield of HO, respectively, while the co-liquefaction process resulted in up to approx. 26 wt% of HO, indicating synergy effect in co-liquefaction of lignin and lignite. The addition of the hematite ore in the co-liquefaction operation produced HO at a very high yield of about 40 wt% at 400 °C for a residence time of 2 h, nearly doubling that of the operation without catalyst. The Produced HO products from the co-liquefaction operations at 400 °C for2 h contain significant concentrations of low molecular weight aromatics at ∼14 mg/g-HO in the presence of non-reduced hematite or goethite, and ∼17 mg/g-HO in the presence of reduced hematite or goethite, compared with only <5 mg/g-HO without iron ore catalyst.