Aluminum Chloride Solution Research Articles

Glycidyl methacrylate co-polymer emulsion-based heat and water-resistant wood adhesive

This work aims to add an epoxy-ended co-monomer to polyvinyl acetate (PVAc) emulsion adhesive-based wood adhesive to improve its resistance to heat and moisture. Here, glycidyl methacrylate (GMA), vinyl neodecanoate (VeoVa), and vinyl acetate (VAc) emulsion copolymers have been created and evaluated as wood adhesives. To prepare the emulsion-based adhesive samples, a polyvinyl alcohol (PVA) solution, aluminium chloride solution, preservatives, and a plasticizer are added. Following that, the poly(VAc–VeoVa–GMA) based adhesive sample is compared with the VAc, VeoVa, and methyl methacrylate (MMA) (poly(VAc-VeoVa-MMA)) co-polymer-based adhesive. Tensile shear strength of wood joints under dry and wet conditions was tested in compliance with EN 204-205 standard to assess the adhesives’ performance. The EN 14257 standard, which defines the shear stress of wood joints at 80 °C, was used to assess the heat resistance of the wood adhesives. Tests on the hardness of films confirmed the results of differential scanning calorimetry, which indicated that the glass transition temperature in the GMA-based adhesive was significantly higher than in the MMA-based adhesive. After 6 h of bonding, EN 204 shows that the tensile shear strength of a GMA-based adhesive increased by 15.56% in a dry environment, by 16.67% in a wet environment and 37.84% heat resistance when compared to a co-polymer-based adhesive based on MMA. The approach that was developed provides a simple and useful way of developing adhesives with enhanced heat, water, and bonding strength resistance.

On the dual crosslinking for functionality enhancement of poly (acrylamide-co-acrylic acid)/chitosan-aluminum (III) ions and its characterization and sensory hydrogel fibers

In this report, we present a dual crosslinking hydrogel fiber made from polyamine saccharides chitosan (CS), synthesized through UV polymerization. This process utilizes Irgacure 2959 and N,N′-Methylenebisacrylamide (MBAA) as initiators, followed by immersion in an aluminum chloride (AlCl3) solution. The resulting hydrogel incorporates a dual crosslinking mechanism, quantitatively studied via Nuclear Magnetic Resonance (NMR) spectroscopy. This mechanism involves chemical crosslinking through radical graft polymerization of acrylamide and acrylic acid onto CS in the presence of MBAA, and physical crosslinking through hydrogen bonding interactions between P(AAm-co-AA) and a metal coordination bond. The mechanical properties of the hydrogel fiber enable it to withstand stresses up to 656 kPa and strains exceeding 300 %. Additionally, the hydrogel fiber exhibits conductivity at 1.96 Scm−1. Serving as a multifunctional material, it acts as a strain sensor and finds utility in optics. Remarkably, it demonstrates the capability to detect human motions such as finger bending and minor deformations like vibrations of the vocal cords. Furthermore, its ability to guide dynamic light makes it promising for optical applications. Consequently, this multifunctional hydrogel fiber emerges as a highly promising candidate for diverse applications in fields such as bioengineering and electronics.

Enhanced Chromium (VI) Removal by Micron-Scale Zero-Valent Iron Pretreated with Aluminum Chloride under Aerobic Conditions

Micron-scale zero-valent iron (ZVI)-based material has been applied for hexavalent chromium (Cr(VI)) decontamination in wastewater treatment and groundwater remediation, but the passivation problem has limited its field application. In this study, we combined aluminum chloride solution with ZVI (pcZVI-AlCl3) to enhance Cr(VI) removal behavior under aerobic conditions. The optimal pre-corrosion conditions were found to be 2.5 g/L ZVI, 0.5 mM AlCl3, and a 4 h preconditioning period. Different kinds of techniques were applied to detect the properties of preconditioned ZVI and corrosion products. The 57Fe Mössbauer spectra showed that proportions of ZVI, Fe3O4, and FeOOH in pcZVI-AlCl3 were 49.22%, 34.03%, and 16.76%, respectively. The formation of Al(OH)3 in the corrosion products improved its pHpzc (point of zero charge) for Cr(VI) adsorption. Continuous-flow experiments showed its great potential for Cr(VI) removal in field applications. The ZVI and corrosion products showed a synergistic effect in enhancing electron transfer for Cr(VI) removal. The mechanisms underlying Cr(VI) removal by pcZVI-AlCl3 included adsorption, reduction, and precipitation, and the contribution of adsorption was less. This work provides a new strategy for ZVI pre-corrosion to improve its longevity and enhance Cr(VI) removal.

Metal-Organic Framework for Aluminum based Energy Storage Devices: Utilizing Redox Additives for Significant Performance Enhancement.

There are various methods being tried to address the sluggish kinetics observed in Al-ion batteries (AIBs). They mostly deal with morphology tuning, but have led to limited improvement. A new approach is proposed to overcome this limitation. It focuses on the use of a redox additive modified electrolyte in combination with framework like materials, which have wider channels. The ordered microporous and interconnected framework of ZIF 67, with large surface area, effectively facilitates the diffusion of aluminum ions. Therefore, AIBs are able to exhibit a superior discharge capacity of 288 mAh g-1 at 0.2 A g-1 current density with robust cycling stability. The addition of potassium ferricyanide as a redox-active species in an aqueous solution of aluminum chloride (supporting electrolyte) leads to significant enhancement in the specific capacity with much higher cycling stability. Al-ion based BatCap devices can be assembled by using ZIF 67 as the cathode, ZIF 67 derived porous carbon as the anode, and a redox additive modified electrolyte. The BatCap device exhibits excellent energy density of 86 Wh kg-1 at a power density of 2 KW kg-1, which is higher than reported aqueous AIBs. The ex situ characterization clearly explains the unexplored mechanism of redox additives in AIBs.

Comparative Evaluation of the Effect of 25% Aluminum Chloride Solution, Chitosan Hemostatic Dressing, and 980 nm Diode Laser on the Pushout Bond Strength of Angelus Bio C-Repair Material: An In vitro Study

Comparative Evaluation of the Effect of 25% Aluminum Chloride Solution, Chitosan Hemostatic Dressing, and 980 nm Diode Laser on the Pushout Bond Strength of Angelus Bio C-Repair Material: An In vitro Study

Development and validation of method of quantitative determination of flavonoids from the above-ground part of Glycyrrhiza glabra L.

The aim of this study was to determine the optimal extraction factors of flavonoids from the above-ground part of licorice (Glycyrrhiza glabra L.) and to develop a method for their quantitative determination by differ-ential spectrophotometry. The object of the study was collected in the Volgograd region during flowering and dried samples of the herb of the medicinal plant. Ethyl alcohol 70% was chosen as the optimal extractant of flavonoids from the studied raw materials. It was found that the extraction of the maximum amount of flavonoid fraction is observed at three times extraction of plant raw material for 30 minutes each in the ratio with extractant 1:30. Quantitative determination of flavonoid compounds was performed by measuring the optical density of coloured complexes formed in extracts from the above-ground part of G. glabra L. with 2.5% aluminum chloride solution. Detection of the optical density of the tested solutions was conducted at a wave-length of 408 nm, corresponding to the maximum of the standard sample solution of rutin (Sigma, USA) after the addition of 2.5% aluminum chloride solution. Determined by differential spectrophotometry method the content of the sum of flavonoids in recalculation on rutin in extracts from the studied samples of plant raw materials of G. glabra L., obtained under the selected conditions, is 4.34±0.06%. The relative error of determination did not exceed 5%. A validation analysis was also conducted, the results of which showed the specificity, linearity and precision of the developed methodology. The studied validation parameters were within the acceptance criteria.

A COMPARATIVE STUDY OF THE COMPONENT COMPOSITION OF THE HERBS OF SOME SPECIES OF THE GENUS ACHILLEA L.

The article presents the results of a comparative study of the component composition of herbs of some species of the genus Achillea L. growing in the Samara region - common yarrow (Achillea millefolium L.), cartilaginous yarrow (Achillea cartilaginea (Ledeb. ex Rchb.) and noble yarrow (Achillea nobilis (L.). Spectrophotometry and high performance liquid chromatography were used as methods of investigation.
 As a result of comparative spectrophotometric analysis of water-alcoholic extracts of common yarrow herbs, yarrow cartilaginous herbs and noble yarrow herbs revealed that the absorption curve of their UV spectra is due mainly to hydroxycinnamic alcohols, in particular chlorogenic and caffeic acids (290 sh. and 330 nm). When aluminum (III) chloride solution was added to the water-alcoholic extracts of yarrow herb from the studied species, a bathochromic shift of the long-wave band at 400 nm was observed due to the flavonoids.
 The content of total flavonoids in the plant raw material is: common yarrow - 0.68±0.01%, cartilaginous yarrow - 0.65±0.02%, noble yarrow - 0.69±0.02%.
 Chlorogenic acid, cynaroside, cosmosiin, apigenin and luteolin were identified in water-alcoholic extracts from the above described species using HPLC method. In addition, the presence of caffeic acid was detected in the water-alcoholic extracts of noble yarrow herbs.
 The content of cosmosiin in the plant raw material is: common yarrow - 0.61±0.01%, cartilaginous yarrow - 0.56±0.02%, noble yarrow - 0.62±0.02%.
 The results of the study can be used in the development of regulatory documentation for medicinal plant material "Yarrow herb" for inclusion in the State Pharmacopoeia of the Russian Federation.

Determining degree of dissociation through conductivity

When ionic compounds dissolve in a polar solvent, they dissociate into separate ions and spread uniformly throughout the solution. The greater the degree of dissociation of an ionic compound, the greater the conductivity of the solution will be. The goal of this experiment was to assess how the degree of dissociation of an ionic compound is impacted by the molarity of the compound in solution, the magnitude of the charge of the ion, and the number of ions it produces upon dissociation. Conductivity was measured as a quantifiable representation of the degree of dissociation. We hypothesized that as the concentration of ions in the solution decreased, the conductivity of the solution would also decrease due to fewer interactions between the ions, resulting in a weaker flow of electrical current. We tested our hypothesis by measuring the conductivity of 0.25 M, 0.20 M, 0.15 M, and 0.10 M solutions of aluminum chloride, potassium chloride, and calcium chloride. The data showed that as the molarities of the solutions decreased, the conductivities of the solutions decreased. We also found that the conductivity of each solution did not decrease by the theoretical factor predicted by the number of ions each compound produced upon full dissociation, leading us to conclude that the impact of the charge magnitude of the ions on the degree of dissociation of the ionic compounds must also be considered.

Development of the method for obtaining and studying vitriol of the iron sulphate based on iron-containing wastes

Especially in recent years, a ferric sulfate solution has occupied the attention as a useful water treatment agent and, particularly, a ferric sulfate solution and a basic ferric sulfate solution have a quick sedimentation speed for the resulting flocs and show good deodorizing ability as compared with a water treatment agent of an aluminum type such as an aluminum sulfate solution and la basic aluminum chloride solution whereby they have been widely used as a water treatment agent for waste water from paper manufacturing industry, from food industry, from chemical industry, leather industry. The purpose and task of the research is to develop the technology for the production of iron sulfate salts. For this purpose used iron filings and sulfuric and hydrochloric acid acid were used for this purpose. Processes of dissolution of ferric waste in acid are well studied and are shown.

Green palladium and platinum recovery by microwave-assisted aluminum chloride solution

A green and sustainable method using microwave-assisted aluminum chloride solution for selective recovery of palladium and platinum from spent catalysts.

Влияние воздействий поверхностно-активных веществ на прочность образцов мерзлых вскрышных горных пород угольных месторождений криолитозоны

The harsh climatic conditions of the cryolithic zone with its long winter period and presence of permafrost soils significantly slow down all technological processes in surface mining. The resistance of frozen rocks at coal mines to digging with mining equipment can be reduced by their preliminary softening with the use of surfactants. The paper discusses the softening effect of aqueous surfactant solutions on samples of frozen overburden rocks. The authors demonstrate that treatment of rocks with solutions of optimal composition and concentration decreases their strength, which makes it possible to enhance the efficiency of In-Pit Crushing and Conveying Systems based on the rotary mechanical shovel in combination with a conveyor as well as the use of continuous miners. Experimental data are presented on the strength properties of artificially made samples of overburden rocks from the Kangalassky coal deposit saturated with surfactant solutions of different concentrations. The authors point out that the highest decrease in the samples strength is achieved when using aqueous solution of aluminum chloride. The results of experiments carried out to establish the effects of distilled water (H2O) and NaCl solutions of different concentrations on the strength properties of fine-grained sandstones from the Elga coal deposit are presented, which confirm that at the temperature of -10°С the maximum reduction of up to 55% is achieved in the strength of the samples, and when the temperature decreases from -10°С to -20°С a slight increase is observed in the sample strength. The authors suggest that the use of surfactants will reduce the strength of the frozen overburden soils, thus making it possible to apply a blast-free mining technology.

ФИТОХИМИЧЕСКИЙ АНАЛИЗ, РАЗРАБОТКА СОСТАВА И ТЕХНОЛОГИИ КАРАНДАШЕЙ С ЭФИРНЫМ МАСЛОМ ЛИСТЬЕВ МЯТЫ ВОДНОЙ, ПРОИЗРАСТАЮЩЕЙ НА СЕВЕРНОМ КАВКАЗЕ

The leaves of water mint growing in the Northern Caucasus were chosen as an object of research. Earlier authenticity of water mint on external and anatomo-diagnostic signs with the purpose of distinction from close species was defined. Based on the results of qualitative reactions and quantitative determination (steam distillation method) in the leaves of water mint was detected essential oil, the content of which was 1,92%. The method of ascending chromatography on paper identified flavonoids: rutin, luteolin, hyperoside. The presence of flavonoids in the raw material was confirmed by cyanidine test (by pink staining) and the formation of a yellow-green complex (with a solution of aluminum chloride (III) 2% alcohol). The spectrophotometric method determined the content of the sum of flavonoids in terms of luteolin, which was 0,72±0,05%. The method of approximate-quantitative spectral analysis analyzed the content of chemical elements from the place of preparation of leaves of water mint in Chegemsky area of KBR. The research revealed 7 trace elements as additional sources possessing antiseptic; analgesic; antipyretic; anti-inflammatory; wound-healing, etc. properties. The optimal bases (beeswax, cocoa butter, paraffin, PEO-4000, PEO-400, tween-80, lanolin, peach oil) for medical pencils with aqueous mint essential oil were selected experimentally. For this purpose, 5 compositions of pencils with a model concentration of essential oil of 2% were selected. The technology of making pencils by pouring method was developed. The estimation of smearing and sticking ability of pencils was carried out. It is established, that the best smearing and sticking ability possesses a pencil of composition №5 which has been chosen as optimum for the further researches.

Synthesis of Nanostructured Alumina from Byproduct Aluminum Filings: Production and Characterization

Aluminum oxide production from aluminum filings, which are a byproduct of several industrial machining processes and cannot be recycled to attain bulk aluminum (Al), is vital due to its wide use in scientific research and industry. The goal of this paper is to produce ultrafine and down-to-the-nanoscale alumina powder (Al2O3), starting from a waste Al filings. The microstructure and composition of the starting Al used were investigated using scanning electron microscopy (SEM), which was equipped with an attached energy dispersive spectrometer (EDS) unit. The results of this investigation confirmed that the starting Al was mainly Al–Mg alloy. Al2O3 was produced using two routes: The first involved the burning of aluminum hydroxide Al(OH)3 that was precipitated from aluminum chloride solution (AlCl3) resulting from dissolving the Al filings in 2M HCl. The second route involved direct precipitation as a reaction product of aluminum chloride with sodium carbonate solution. The Al2O3 produced using both routes, as well as the intermediate product Al(OH)3, were studied by SEM. The results demonstrate that the nanoscale range size was reached after milling of the produced Al2O3. Following thorough washing with distilled water, the EDS and the XRD techniques confirmed the formation of Al2O3, with no residual salt detected. The EDS results showed that the ratios of Al and O in the produced Al2O3 were about 96% of the ideal compound ratios. The XRD analysis also revealed the amorphous structure of the standard and the produced Al(OH)3, whereas the phases of the produced Al2O3 were either crystalline or amorphous. In our study, the Al2O3 percentage yield was about 77%, and this value obviously depends on the percentage of Al dross in the original Al filings. Overall, this research provides a novel contribution to the production of alumina powder in the nano-range starting from an aluminum filings byproduct, thereby reducing the dependence on known sources of aluminum.

РАЗРАБОТКА И ВАЛИДАЦИЯ СПЕКТРОФОТОМЕТРИЧЕСКОЙ МЕТОДИКИ ОПРЕДЕЛЕНИЯ СОДЕРЖАНИЯ ФЛАВОНОИДОВ В ПУПАВКИ КРАСИЛЬНОЙ ТРАВЕ

The aim of this work is development and validation of a spectrophotometric technique for quantification of total flavonoids in terms of rutin in potentially medicinal plant Anthemis tinctoria herb. According to the literature, Anthemis tinctoria is used in folk medicine as a hepatoprotective, hemostatic and means, and its extracts in the experiment exhibit antimicrobial, cytostatic and antioxidant activities. In this work, we used sample of Anthemis tinctoria herb harvested in the summer of 2021 during the period of mass flowering in vicinity of Perm city (valley of the Vasilievka river, Adishchevo railway station). The raw materials were dried at room temperature, with sufficient ventilation, without direct exposure to sunlight, stored separately from other types of raw materials. According to the experiments the optimal conditions for determining of total flavonoids: grinding the raw material to a size passing through a sieve with a diameter of 1 mm, the optimal concentration of ethyl alcohol extractant is 50%, the analytical wavelength is 410 nm, the extraction time in a boiling water bath is 45 minutes, the ratio of extraction and complexing agent - 2% alcohol solution of aluminum chloride - 2:5. The technique was validated in accordance with the requirements of State Pharmacopeia of Russia 14th edition, the relative error of determination with a reliable probability of 95% was 4.00%. The technique can be used in further work to conduct studies of biological activity.

DEVELOPMENT OF METHODS OF STANDARDIZATION OF FLOWERS OF SPREADING MARIGOLD (TAGETES PATULA L.)

The spreading marigold (Tagetes patula L.), the family Aster (Asteraceae), or Composite (Compositae), is a prospective source of flavonoids. The aim of the study is to develop methods of standardization of marigold flowers rejected, consisting in determining the identity of this raw material and the quantitative determination of biologically active compounds. As a result of a comparative chromatographic study, the presence of flavonoids was detected upon detection at a wavelength of 254 and 366 nm and before and after reaction with an alcohol solution of aluminum chloride. The presence of patuletin and patulitrin was confirmed in extracts of different varietal forms of Tagetes patula L.. Using column chromatography on silica gel L 40/100, two flavonoid substances were isolated patuletin (3,5,7,3′,4′-pentahydroxy-6-methoxyflavone) and patulitrin (7-O-β-D-glucopyranoside of 3,5,7,3',4′-pentahydroxy-6-methoxyflavone), which have been identified by UV-, 1H-NMR -, 13C-NMR-spectroscopy and mass spectrometry, as well as acid hydrolysis. In the solvent system chloroform- ethanol-water (26 : 16 : 3) Rf values of patuletin and patulitrin are about 0.7 and 0.4, respectively. It was found that patulitrin is the main flavonoid in the flowers of spreading marigold and determines the character of the absorption curve of the electronic spectra of water-alcohol extraction from this raw material. During the quantitative analysis of the total flavonoids in the flowers of spreading marigold, it is necessary to recalculate the content of active substances to the dominant and diagnostically significant flavonoid patulitrin. It was determined that the content of the total flavonoids in the studied samples of flowers of different varieties of the spreading marigold varies from 4.36±0.02% to 11.71±0.05% (calculated on patulitrin).

Plaster board waste (PBW) – A potential fluoride leaching source in soil/water environments and, fluoride immobilization studies using soils

Plaster board waste generated from industries, usually contains major proportion of calcium as calcium sulfate. In addition, fluoride is remarkably one among the constituents of this waste material which leaches off into the soil and aquatic environments and causes fluoride pollution. In order to simulate how the dumping of PBW causes fluoride contamination in soil and water sources, shaking and stirring based batch-mode leaching studies were conducted. These studies explored the leaching of fluoride as a function of particle size, agitation time, pH of the leaching solvent (distilled water), L/S (water: PBW) ratio, temperature and electrolytes. It was explored that 1 g of plaster board waste contains18.54 mg F per gram of PBP. High leaching of 3.72 mg F per liter was studied at pH 6.02 with Ca2+ and TDS contents of 1050 mg L−1 and1640 mg L−1 respectively. The influence of sodium electrolytes such as chloride, nitrate, hydrogen carbonate, carbonate, sulfate, borate, phosphate and acetate on the leaching of fluoride from PBW was studied. The influence of fluoride leaching by sodium phosphate recorded a high value of 12.75 mg L−1 with no detectable amount of calcium ions. The influence of eight electrolytic mixtures each containing five sodium electrolytes on fluoride leaching corroborated the highest leaching in mixtures containing phosphate followed by hydrogen carbonate/carbonate. Solutions of calcium and aluminium chloride and their mixture were used to measure the rate of leachable fluoride in solution. Furthermore, the fluoride leaching at different temperatures and acids was studied. Naturally occurring soils when blended with PBW were observed to immobilize fluoride and lessened the amount of leaching fluoride in water. Various characterization studies such as FTIR, Raman, FESEM (with EDS), XRD and XPS were carried out for PBW and its treated samples using different electrolytes. Fluoride leaching proportionate to the precipitation of carbonate and phosphate was recorded in the case of appropriate electrolyte and mixtures.

The Protective Effect of Berberine Against Memory Impairment Induced by Intrahippocampal Injection of Aluminium Chloride in Rats

Background and Objectives: Aluminum is a component of environmental pollutants, which causes neurotoxicity. Berberine is in the group of plant-derived alkaloids such as barberry and its beneficial therapeutic properties in various diseases have been proven. The aim of the present study was to investigate the protective effect of berberine on aluminum-induced neurotoxicity. Methods: In this experimental study, 32 male Wistar rats were randomly divided into 4 groups: sham, berberine-receiving sham, lesions-seeing and berberine-receiving lesions. To induce neurotoxicity, a solution of aluminum chloride (AlCl3) dissolved in distilled water was injected at 5 µL at a dose of 0.37 mg/kg to the left of the dorsal hippocampus. The treated rats received 100 mg/kg of berberine daily from one hour before surgery to one week after surgery and orally. In the fourth week, all groups were tested for behavioral learning and memory using the shuttle box. At the end, malondialdehyde, protein, ROS levels and acetylcholinesterase activity were measured. The results were analyzed using one-way ANOVA test and Tukey test. Results: In the treated AlCl3 group compared to the AlCl3 group, the initial delay was not significantly different but the delay during transit was significantly increased. MDA and ROS levels and acetylcholinesterase activity showed a significant decrease. Conclusion: The results of this study showed that although treatment with berberine in the lesion group by aluminum chloride did not cause a significant difference in learning in rats, but it significantly improved memory, significantly reduced malondialdehyde, significantly reduced oxygen free radical levels and significantly reduced activity. Acetylcholinesterase and it can be said that berberine with antioxidant properties improved memory and neuroprotection against neurotoxicity caused by aluminum chloride.

Homogeneous precipitation of Mg/Al layered double hydroxide from concentrated metal salt solution under hydrothermal conditions

Homogeneous precipitation using urea hydrolysis under hydrothermal conditions has been examined to prepare carbonate type magnesium aluminium layered double hydroxides (Mg/Al-CO3 LDHs). To obtain well-crystallized Mg/Al-CO3 LDHs as single phase, low concentration starting solutions have been used, resulting in the small amount of product from a batch. In this study, concentrated starting solution of magnesium chloride and aluminum chloride (total metal salts concentration of 1.0 ​M) was used to achieve bulk syntheses. The reaction conditions were optimized to obtain well-crystallized Mg/Al-CO3 LDH of rosette-like shape with the radius of ca. 2–4 ​μm in a large scale (7.6 ​g from 160 ​mL container). The parameters including heating rate and reaction temperature were found to be important to avoid the formation of by-products, and the Mg/Al ratio in the initial solution influenced the composition and morphology of the products. The heating rate of 8 ​°C/min and the reaction temperature at 100oC successfully led to single-phase Mg/Al LDHs.

Phytochemical study of the plant species Bidens pilosa L. (Asteraceae) and Croton floccosus (Euphorbiaceae).

Background: Given the chemical richness of medicinal plants ( Bidens pilosa L. and Croton floccosus) in Ecuador, they are considered the natural source of numerous medicines. Methods: The leaves were dried at 40°C and 50°C and the extracts were characterized by means of phytochemical screening, verifying the presence of secondary metabolites such as alkaloids, reducing sugars, phenols, flavonoids, tannins and saponins. Three extraction processes were carried out, with two solvents of different polarities: hexane and ethanol. The extraction methods that were applied to the leaves of the plants were Soxhlet, ultrasonic bath and maceration, the latter two at room temperature and Soxhlet at the boiling temperature of the solvent. Determination of the total content of phenols and flavonoids is carried out using the Follin-Ciocalteau colorimetric reaction, Quercetin standard, Aluminum Chloride solution measured with a UV-Vis spectrophotometer. The antioxidant activity was performed with the DPPH radical and measured with the same equipment. Results: The highest content of total phenols obtained by employing the Soxhlet method for extraction when the material was dried at 50°C was 48.609 ± 0.370 mg GAE/g of dry sample for Bidens pilosa L. while in the case of Croton floccosus it was 128.212 ± 0.601 mg GAE/g of dry sample obtained from the extraction by means of maceration. Finally, the antioxidant activity against the 1.1-diphenyl-2-picryl-hydrazyl radical was determined, and it was found that the Bidens pilosa L. species performed better and responded better to the test, with an IC 50 value of 239.33 µg/mL, than Croton floccosus (IC 50 of 644.125 µg/mL). Conclusions: The following preliminary phytochemical study of the Bidens pilosa L. and Croton floccosus plants provided important information on the content of secondary metabolites and response to the DPPH radical reported for the first time in Ecuador, which may be future use for medicinal application.

Differentiating the Structure and Dynamics of Solute-Bound Vs. Bulk Water in Deep-Eutectic Aqueous AlCl3 Solutions

Aqueous solutions of aluminum chloride exhibit a deep eutectic (-52˚C) that is likely due to solute-directed formation of complex network structures in the solvent. It is well known that the solute-bound solvent must have a distinct chemical environment from that of the bulk solvent. Commonly used vibrational spectroscopic measurements of aqueous salt solutions are not selective enough to directly identify distinct water environments in solution. However, variable-temperature 1H-NMR spectroscopy of aqueous solutions, specifically those with high charge density salts, can distinguish water directly bound to the cation from water of the bulk solution. This unique ability to resolve characteristic water peaks by NMR spectroscopy affords the opportunity to explore the hydration structure and dynamics of deep-eutectic aqueous solutions. The aqueous AlCl3 system is an excellent model to study solution structure since we can exploit the high charge density of the ions for which strong ion-dipole interactions are structure-directing to the solvent waters, allowing resolution of distinct water chemical environments. We conducted a thorough investigation of the composition- and temperature-dependent solution structure of the AlCl3 : water system using 1H-NMR spectroscopy, and X-ray and neutron diffraction. The room-temperature proton chemical shift of water proceeds downfield with increasing salt concentration until AlCl3•22H2O, the eutectic composition, after which further increasing concentration results in an upfield chemical shift (see Figure.) Using VT-NMR, we can resolve the first-nearest neighbor water signals from the bulk signal upon cooling. 1H-NMR T1 and T2 relaxation measurement of the distinct water environments reveal stark differences in proton mobility for compositions on the water-rich versus AlCl3-rich sides of the eutectic, implying significant changes in hydration structure. To evaluate the extent to which these changes are structural, a parallel set of composition- and temperature-dependent neutron and X-ray diffraction experiments demonstrate that both cations and anions exhibit significant structure-directing influences on the solution, which we hypothesize underlies deep eutectic behavior in aqueous solutions. Figure 1