Aqueous Solutions Of Sodium Salts Research Articles

Phase partitioning nature, interaction forces and thermodynamic parameters of triton X-100 and bovine serum albumin mixture: impacts of the composition of Na-salt

Herein, the assessment of interactions between a non-ionic surfactant (NIS) triton X-100 (TNX-100) and a globular protein bovine serum albumin (BSA) was explored through the determination of clouding nature in aqueous solution of sodium salts (Na-salts). Sodium chloride (NaCl), sodium acetate (NaOAc), sodium carbonate (Na2CO3), sodium oxalate (Na2Oxal), sodium sulphate (Na2SO4), and sodium phosphate (Na3PO4) have been chosen to assess their impacts on the clouding nature of TNX-100 + BSA mixture. The estimated cloud point (CP) values were noticed to be lowered with the enhancement of [Na-salts]. The lessening of CP values has been explained by the salting out effect of anions. The calculated standard Gibbs free energy change ( Δ G c o ) was positive at all examined conditions which illustrates the nonspontaneity of phase change. The standard enthalpy ( Δ H c o ) and entropy ( Δ S c o ) changes exhibited negative values at low contents of aq. Na-salts and positive values at high aq. Na-salts content. These consequences illustrate the presence of electrostatic interactions at low Na-salts concentration and hydrophobic interactions at high Na-salts concentration. Furthermore, enthalpy-entropy parameters were successfully computed and explained with proper clarification.

Solubility modeling of hydrogen sulfide in aqueous sodium salt solutions

Accurate solubility prediction of hydrogen sulfide in aqueous electrolyte solutions is critical for gas exploitation and geological storage. However, there is a lack of electrolyte Equation of State model that can accurately calculate the solubilities of hydrogen sulfide in aqueous electrolyte solutions over wide ranges of temperature, pressure, and salt molality. This work presents a modeling study on the solubilities of hydrogen sulfide in pure water and several aqueous sodium salt solutions. The thermodynamic framework used in this work is an electrolyte version of Cubic-Plus-Association Equation of State. The model’s temperature-dependent ion-gas binary interaction parameters are obtained by regressing the experimental solubilities in the aqueous electrolyte solutions. The modeling results show that the electrolyte Cubic-Plus-Association Equation of State can satisfactorily correlate the solubilities of hydrogen sulfide in aqueous electrolyte solutions over wide ranges of temperature, pressure, and salt molality. For the typical water–sodium chloride–hydrogen sulfide system, the model can satisfactorily correlate the gas solubilities with the mean relative deviation being 6.2%, with the temperature up to 593.95 K, pressure up to 32.30 MPa, and salt molality up to 6.0 mol⋅kg−1 water. Moreover, the salting-out effects and model adaptability are analyzed and discussed.

SYNTHESIS AND THERMAL CHARACTERISTICS OF WATER-SOLUBLE BLOCKED O-TOLYLISOCYANATE

Synthesis of latent reagents, in particular isocyanates, in a water-soluble form is a promising direction of chemical research. The replacement of isocyanates with their blocked analogues allows solving several problems: increasing safety in the use and storage of such toxic compounds as isocyanates, facilitating multi-stage synthesis in active media, increasing the selectivity of the main reaction, reducing the toxicity of reagents. In addition, due to the possibility of carrying out the blocking reaction of isocyanates in an aqueous media, the environmental safety of the process of their production is increased and the yield of the product is improved. In order to synthesize a water-soluble latent monoisocyanate for the modification of polymer systems, including water-soluble biopolymers, water-soluble sodium 6-(o-tolylcarbamoylamino)hexanoate was synthesized by the interaction of ortho-tolyl isocyanate with an aqueous solution of sodium salt of 6-aminohexanoic acid. The optimal temperature conditions for the synthesis of water-soluble blocked ortho-tolyl isocyanate were determined. The structure of the reaction product was proved using methods of IR- spectroscopy with Fourier transform and NMR 1H spectroscopy. According to the data of thermogravimetric analysis in dynamic mode and pyrolytic mass spectrometry the temperature range of the thermal dissociation of water-soluble ortho-tolyl isocyanate blocked by the sodium salt of 6-aminohexanoic acid ranges from 100 to 140°C and is wider than the temperature range of the thermal dissociation of the hydrophobic compound - ortho- tolyl isocyanate blocked by ε- caprolactam.

Volumetric Properties of Aqueous Sodium Salt of Amino Acids as CO2 Capture Solvent

Objectives: To produce new and accurate data of density of aqueous solution of amino acid salts at different temperatures and to correlate it with molality. Methods: The densities of aqueous solutions of sodium salts of Amino acids such as L-cysteine, L-leucine, L-proline and L-valine have been measured using double-arm Pycnometer, placed in a transparent glass-walled water bath having thermal stability of (0.01 K) at concentrations range (0.01 to 0.15) mol L-1 and at 298.15, 303.15, 308.15, and 313.15 K. From density data ahead, apparent molar volumes (Vϕ ), the partial molar volumes (Vϕ 0), expansion coefficient (E¥) and Hepler’s constant ( ¶ 2Vϕ 0=¶ T2) were calculated and analysed on the basis of the intermolecular interaction and molecular structure. Findings: The densities are observed to increase with concentration and decrease with increasing temperature. The positive values of partial molar volume (Vϕ 0) indicate strong sodium amino acids -water interactions. Novelty: For studied aqueous sodium salt solution of Amino acids, such properties have not yet been reported in the open literature and at such a lower concentrations range (0.01 to 0.15) mol L-1. Keywords: Density; Sodium Salt Amino Acid; Apparent Molar Volume; Helper’s Constant

Studies of the Formation of Inclusion Complexes Derivatives of Cinnamon Acid with α-Cyclodextrin in a Wide Range of Temperatures Using Conductometric Methods.

The electrical conductivities of aqueous solutions of sodium salts of trans-4-hydroxycinnamic acid (trans-p-coumaric acid), trans-3,4-dihydroxycinnamic acid (trans-caffeic acid), trans-4-hydroxy-3-methoxycinnamic acid, (trans-ferulic acid) and trans-3-phenylacrylic acid (trans-cinnamic acid) with α-cyclodextrin were measured in the temperature range of 288.15 K–318.15 K. For the first time in the literature, using the limiting molar conductivity obtained from conductivity measurements, the values of the complexation constants (Kf) of the salts of phenolic acid derivatives with α-cyclodextrin were determined using a modified low concentration chemical model (IcCM). An attempt was also made to analyze the individual thermodynamic functions , and describing the complexation process as a function of temperature changes. The obtained results show that the process of formation of inclusion complexes is exothermic and is spontaneous.

Effect of Adjuvant, Concentration and Water Type on the Droplet Size Characteristics in Agricultural Nozzles

One of the goals of adding adjuvants to agricultural spray solutions is to enhance the droplet size characteristics of this spray. Droplet size, in turn, has an influence in the deposited spray quality, in addition to the drift and losses of spray to off-target places. The aim of this research was to evaluate the effect of adding adjuvants to two types of water from different sources on the droplet size characteristics. Two types of adjuvants were employed in the tests: the active substance content of the first adjuvant was a 50% aqueous solution of sodium salt of alkylbenzenesulfonic acid—10% (HY), whereas the second was from rapeseed oil (natural origin)—85% (OL). Both adjuvants were tested in two concentrations: the first was with the concentration recommended by the manufacturer (100%), whereas the second concentration was 50% of the recommended dose. Two types of water from different sources were used in the tests: the first was from a village in the eastern part of Poland (WS), whereas the second was tap water from the city of Lublin, Poland (WUP). Dv0.1, Dv0.5, or volume median diameter (VMD), Dv0.9, Sauter mean diameter (SMD), relative span (RS), and the droplet size distribution were measured and calculated as characteristics of the droplet size. Results showed that the source of water affected the influence of adding adjuvant to the spray solution. Water from the WS source with adjuvant resulted in a numerical decrease in the Dv0.5 values in the percentage of droplet size range below 150 µm, whereas water from the WUP source resulted in an increase in these values (except when adding the HY adjuvant at 50% concentration). Adjuvant concentration significantly (p < 0.05) influenced the features of Dv0.9, SMD, and RS. Adding the OL adjuvant type numerically decreased the percentage of droplet size below 150 µm, and the Dv0.5 values, but only when the WS water source was used.

Mass transfer and capture of carbon dioxide using amino acids sodium aqueous solution in microchannel

Capture and storage of CO2 are important to restrain the greenhouse effect. The amino acid salt solution as a new type of CO2 absorbent shows good application potential. Besides, microchannel has a unique enhancement to mass transfer, which is conducive to promote CO2 capture. The absorption performance of CO2 into aqueous solutions of sodium salts of l-threonine, l-valine, l-alanine and glycine in the microchannel was investigated. It was found that the CO2 absorption rate of four sodium amino acid aqueous solutions under the same condition follows in the order: ñ (sodium glycinate) > ñ (sodium l-alaninate) > ñ (sodium l-valinate) > ñ (sodium l-threoninate). The sodium glycinate aqueous solution has maximum CO2 absorption ability, thus the mass transfer and capture of CO2 absorbed into the sodium glycinate aqueous solution were studied systematically. The effects of operating conditions including gas flow rate, liquid flow rate, and sodium glycinate concentration on the specific surface area, overall volumetric mass transfer coefficient, overall mass transfer coefficient and absorption fraction of CO2 were explored. Furthermore, a new correlation was proposed to predict the volumetric mass transfer coefficient.

Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks

Improving geothermal systems through hydraulic stimulation to create highly permeable fractured rocks can induce seismicity. Therefore, the technique must be applied at a moderate intensity; this has led to concerns of insufficient permeability enhancement. Adding chemical stimulation can mitigate these issues, but traditional methods using strong mineral acids have challenges in terms of achieving mineral dissolution over long distances and highly variable fluid chemistry. Here, we demonstrate a novel chemical stimulation method for improving the permeability of rock fractures using a chelating agent that substantially enhances the dissolution rate of specific minerals to create voids that are sustained under crustal stress without the challenges associated with the traditional methods. Applying this agent to fractured granite samples under confining stress at 200 °C in conjunction with 20 wt% aqueous solutions of sodium salts of environmentally friendly chelating agents (N-(2-hydroxyethyl)ethylenediamine-N, N′, N′-triacetic acid and N, N-bis(carboxymethyl)-l-glutamic acid) at pH 4 was assessed. A significant permeability enhancement of up to approximately sixfold was observed within 2 h, primarily due to the formation of voids based on the selective dissolution of biotite. These results demonstrate a new approach for chemical stimulation.

Conductance studies of sodium salts of selected dicarboxylic acids in water at temperatures of 283.15 K to 313.15 K

The electric conductivities of aqueous solutions of sodium salts of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid and azelaic acid were measured from T = (288.15 to 313.15) K, in the concentration range 0.0003 < c/mol∙dm−3 < 0.0175. In order to determine the limiting molar conductivity (DA2-0) of the tested electrolytes, Barthel’s low concentration chemical model (lcCM) was used.Based on the obtained data, the limiting molar conductance (λA2-0), the diffusion coefficients (DA2-0), and the Eyring’s enthalpies of activation of charge transport (ΔH*) were calculated for the studied anions. The changes observed in the obtained values were also analyzed with regard to the numbers of –CH2- groups in the aliphatic chain of the tested acids.

Nickel(II) complexes of m-ethylphenylxanthate with nitrogen donors and their biological screening

A series of five adducts of m-ethylphenylxanthate of nickel(II) [(m-C2H5C6H4OCS2)2Ni] with nitrogen donors have been synthesized in 1:2 molar ratio by the reaction of aqueous solution of NiCl2.6H2O with aqueous solution of sodium salt of m-ethylphenylxanthate. These metal complexes are reacted with nitrogen donors to give donor stabilized complex, [(m-C2H5C6H4OCS2)2(L)2Ni] where, L= 2-, 3-, 4-ethylpyridine and 2-, 3-chloropyridine. The adducts have been characterized by elemental analysis, molar conductance and magnetic susceptibility measurements, IR, electronic, mass spectral studies, thermogravimetric analysis, powder X-ray diffraction, biological studies. The spectral studies have revealed the octahedral coordination of ligands around Ni(II) metal ion. The adducts are found to be paramagnetic and non-ionic in nature. Mass studies show the monomeric nature of the adducts. The complexes have depicted potential antifungal activity against Bipolaris maydis and Rhizoctonia solani. Some of the synthesized Ni(II) xanthate complexes display in vitro cytotoxic efficacy against human cancer cell lines.

Molar conductivity and association constants of sodium salts of selected cinnamic acids in water at temperatures from 288.15 to 318.15 K

The electrical conductivities of aqueous solutions of sodium salts of cinnamic acid, 4-hydroxycinnamic (p-coumaric) acid, 3,4-dihydroxycinnamic (caffeic) acid, 4-hydroxy-5-methoxycinnamic (ferulic) acid and 3,5-dimethoxy-4-hydroxycinnamic (sinapinic) acid were measured over the temperature range (T) of 288.15 to 318.15 K at 5 K intervals. The limiting molar conductivity Λmo and ionic association constants (KAo) were obtained using the low concentration Chemical Model (lcCM). The limiting ionic conductivity and the Eyring's activation enthalpy of charge transport of the investigated anions were determined.

Anion-Specific Effects on Activity Coefficients in Aqueous Solutions of Sodium Salts: Modeling with the Extended Debye–Hückel Theory

The extended Debye–Huckel theory, which allows for concentration variation of electrolyte solution static permittivity, is employed to predict activity coefficients in aqueous solutions of sodium salts with various univalent anions (NaCl, NaBr, NaI, NaNO3, NaClO4 and NaSCN) at ambient conditions. Calculations without empirical adjustments reproduced the activity coefficients for NaI in the concentration range up to 6 mol·kg−1 and for NaSCN up to 2 mol·kg−1. In the case of other solutions, calculations underestimate water activity coefficients and overestimate mean ionic activity coefficients at concentrations beyond 0.5 mol·kg−1. In order to improve the representations, the model was extended to include ion pairing, which resulted in a better agreement between calculated activity coefficients and experimental data, especially for NaNO3. The ion pairing equilibrium constants were estimated and compared with available literature values. The extent of ion pairing was found to increase in the sequence NaI < NaSCN < NaBr < NaCl < NaClO4 < NaNO3, with violation of the Collins rule in the case of polyatomic oxygen-containing anions.

Conductance studies of aqueous solutions of sodium salts of selected benzoic acid derivatives at temperatures from (288.15 to 318.15) K

The electrical conductivities of aqueous solutions of sodium salts of benzoic acid, 2-hydroxybenzoic (o-salicylic) acid, 3-hydroxybenzoic (m-salicylic) acid, 4-hydroxybenzoic (p-salicylic) acid, 3,4-dihydroxybenzoic (protocatechuic) acid, 4-hydroxy-3-methoxybenzoic (vanillic) acid and 4-hydroxy-3,5-dimethoxybenzoic (syringic) acid were measured over a temperature range (T) of 288.15 to 318.15 K and a concentration range (c) of ~1 · 10−4 to ~1,5 · 10−2 mol·dm−3. The results were analyzed with Barthel's low concentration Chemical Model (lcCM) to obtain the ionic association constants (KAo) and the limiting molar conductivity (Λmo) of the electrolytes. The limiting ionic conductivity and hydrodynamic radius of the investigated anions were determined, as well as the value for Eyring's activation enthalpy of charge transport. The study also analyzes and discusses the influence of hydrolysis of the salts on their limiting molar conductivity.

Hydrogenation of p-Nitrobenzoic Acid by Gold and Palladium Nanoparticles Immobilized Within Macroporous Amphoteric Cryogels in Aqueous Solution

Aqueous solutions of sodium salt of p-nitrobenzoic acid (p-NBA) were hydrogenated in mild conditions in the presence of palladium (PdNPs) and gold nanoparticles (AuNPs) immobilized within macroporous amphoteric cryogel based on N,N-dimethylaminoethylmethacrylate (DMAEM) and methacrylic acid (MAA). The morphology of the macroporous catalyst DMAEM-co-MAA/AuNPs was characterized using SEM. The pore sizes of sponge-like porous structure of cryogels are in the range of 5–40 µm, while the average sizes of AuNPs immobilized within the macroporous amphoteric cryogel are 80 ± 20 nm. The reduction of p-NBA to p-aminobenzoic acid (p-ABA) and further to by-products p,p′-azodibenzoate and sodium 4-(4-aminobenzamido)benzoate was confirmed by Raman and 1H NMR spectroscopy. The conversion degree, kinetic parameters, and activation energies of hydrogenation of p-NBA were found.

The Study of Ultrasonic Velocity and Acoustical Parameters of the System Containing Aqueous Solution of Sodium Salt of 4-Amino Salicylic Acid at Different Temperatures

The Study of Ultrasonic Velocity and Acoustical Parameters of the System Containing Aqueous Solution of Sodium Salt of 4-Amino Salicylic Acid at Different Temperatures

Conductance studies of sodium salts of some aliphatic carboxylic acids in water at different temperatures

In this paper the electric conductivities of aqueous solutions of sodium salts of aliphatic carboxylic acids of the H(CH2)nCOOH [n=0 to 9] types were measured from T/K=(283.15 to 313.15) in the concentration range 0.0005<c/mol∙dm−3<0.0200. In terms of the limiting molar conductance (Λο) the measured conductance results have been analyzed by the Fuoss – Justice conductance-concentration equation. From these data the carboxylic ionic contributions (λH(CH2)nCOO−o) to the limiting molar conductance have been estimated. In this paper the Eyring's enthalpies of activation of charge transport ΔH⁎ were also calculated. The variations of λH(CH2)nCOO−o and ΔH⁎ as the function of the aliphatic chain length of analyzed carboxylic acids were determined.

Aggregational Attitude of Hexadecyltrimethylammonium Bromide in Aqueous Solutions of Sodium Salt at 298.15k

This research reports micelle formation of hexadecyltrimethylammonium bromide and the dependence of aggregation number on the array of sodium salts in aqueous solution. Critical micelle concentration, degree of micelle ionization, and aggregation number were obtained from electrical conductivity measurement. Pseudo-phase separation model was used to evaluate and discussed standard Gibb’s free energy of micellization. It was observed that hexadecyltrimethylammonium bromide critical micelle concentration decreases while aggregation number increases. Amongst the sodium salt, disodium hydrogen phosphate was found to have the highest tendency in reducing hexadecyltrimethylammonium bromide critical micelle concentration. The sodium salts with the highest valency anion strongly promote micellization of hexadecyltrimethylammonium bromide, indicating the dependence of aggregation phenomenon on the availability of anion.

Comparison of Electrocalorimetric and Cooling Methods to Determine Specific Heat of Aqueous Solutions of the Sodium Salt Carboxymethylcellulose

This article includes the results of experimental research, determining specific heat of water, glycerin, rapeseed oil and aqueous solutions of carboxymethylcellulose sodium salt. Two research methods were used during measurements. The first one uses Newton’s law of cooling. The second one uses electrocalorimetric measurements. The average calculated values of determined parameter for model liquids did not exceed 1 % error in cooling method and did not exceed 2 % error in calorimetric method. Good conformity of both methods enabled to use them in measurements of liquids with unknown values of specific heat C. In case of carboxymethylcellulose sodium salt, together with increasing concentration, specific heat increases. Significant impact on obtained results has also molar mass M. The highest values C, were obtained for carboxymethylcellulose sodium salt with a molar mass 700,000 kg/kmol and concentration 0.005 kg p/kg within the range of temperatures (303–325) K. Obtained result was over 19 % higher than water.

Triptycene based chemosensors for selective detection of mercury(II)/iron(III) in aqueous medium

Synthesis and characterization of two trisubstituted triptycene derivatives in high yields are being reported. Aqueous solutions of sodium salt of 2,6,14- and 2,7,14-triptycenetripropiolic acids (1c and 2c) have shown high selectivity for Hg2+ and Fe3+ ions, through quenching of fluorescence intensity, when tested in presence of other metal ions in pure aqueous medium. In addition, pH dependence of fluorescence quenching has been studied. Binding stoichiometry between probes and metal ions (Hg2+ and Fe3+) has been studied using Job’s plot, and corresponding association constant has been evaluated. 1c and 2c are the unique examples of triptycene based tripods that act as chemosensors for selective detection of metal ions.

Surface tension, surface excess concentration, enthalpy and entropy of surface formation of aqueous salt solutions

Surface tensions of aqueous solutions of sodium salts of chloride, bromide and nitrate; potassium salts of chloride, bromide and nitrate; lithium chloride and potassium iodide has been determined experimentally at different concentrations and temperatures ranging from 0.10 to 2.00molkg−1 and 10–30°C, respectively. Concentration and temperature dependence of the surface tension of the selected salts has been studied for further estimation of surface excess concentration, enthalpy and entropy of surface formation. The results show that the surface excess concentration decreases linearly with concentration but remains almost constant with the variations of temperature. Similarly the enthalpy of surface formation was observed to decrease with concentration but remained almost constant with the change in temperature. The entropy of surface formation was found to decrease with concentration in most cases.