Aqueous Solutions Of Inorganic Acids Research Articles

The study on distribution coefficient of polonium between tri-octylphosphine oxide (TOPO) and tri-butylphosphate (TBP) in toluene and cyclohexane and selected inorganic acids

AbstractIn this work the distribution coefficients (D) of polonium between 0.1 mol dm−3 TOPO/toluene; TOPO/cyclohexane; TBP/toluene and TBP/cyclohexane and aqueous solutions of inorganic acids (HCl, HNO3, H2SO4 and H3PO4) were determinated. The molarities of inorganic acids were between 0.5 and 12.0 mol dm−3. The activity of extracted Po-209 was measured by means of liquid scintillation counting. The best result was obtained for TOPO/toluene and 2 mol dm−3 H2SO4 system (D = 62 ± 9). The most stable conditions of extraction were found for TOPO/toluene-HCl system.

Corrosion Properties of Titanium Obtained by the Method of Powder Metallurgy

We study the corrosion rate of titanium obtained by the method of powder metallurgy in aqueous solutions of inorganic acids. It is shown that the addition of titanium hydride to the original powder mixture increases the density of the material, decreases the actual contact area with aggressive media, and hence, enhances its corrosion resistance. However, we did not establish any clear relationship between the content of titanium hydride in the original powder mixture and the corrosion rate of the compacted material.

The discharge current effect on the electrolyte nonequilibrium mass transfer rate under the action of an atmospheric glow discharge

The mass transfer rates obtained from experiments for aqueous solutions of inorganic acids and alkali are presented. It is shown that the nonequilibrium evaporation rate versus the discharge current characteristic has an S-shaped form. It is suggested that the break area in the current curve corresponds to the change of the mass transfer mechanism.

Effect of etching and chemomechanical polishing on the surface quality of polycrystalline ZnSe

We examine the etching and chemomechanical polishing of zinc selenide with the use of aqueous solutions of inorganic acids and bases of different concentrations. The results are used to develop a procedure for chemomechanical polishing of polycrystalline zinc selenide.

Mechanical effects of aqueous solutions of inorganic acids and bases on a natural active clay

The mechanical properties of clays are strongly affected by the pore fluid's chemical composition. Experimental and theoretical analyses have investigated the mechanical effects of exposing clays to aqueous solutions with different salt concentrations and to organic solvents, highlighting the different role of the various cations. With the exception of clay suspensions, no attention has been paid to the effects of pore fluid pH variations on the mechanical behaviour of clays, although clay may be exposed to inorganic acids or bases in many environmental conditions and man-induced situations. The aim of this paper is to investigate how the mechanical behaviour of active clays is affected by pore fluid acidity and alkalinity. Only aqueous solutions of inorganic acids and bases are considered in this study; the rheology of clay suspensions is not investigated. The tests were performed on a natural Na-bentonite, and focused on the influence of pore fluid acidity/alkalinity on the liquid limit, one-dimensional compressibility, permeability and residual strength. Any clay lattice dissolution was found to have negligible mechanical effects. All mechanical effects were reversible, provided the clay was subsequently exposed to an appropriate cycle of acid or alkaline solutions. H+ protons revealed a strong aptitude for adsorption even at low concentrations, causing the desorption of previously adsorbed cations, large volume compression, greater stiffness and residual shear strength. In contrast, exposure to NaOH produced swelling at low concentrations and compression at high concentrations. As a result, the mechanical properties of active clay are strongly affected by even relatively small variations in pore fluid pH. The experimental results are consistent with the concepts of cation exchange on permanently charged surface sites and acid–base reactions on variably charged sites (mainly located at clay edges), and with the assumption of a variable diffuse double layer thickness depending on pore fluid ionic strength. Appropriate sequences of chemical exposures highlight the significant effects of acid–base reactions at particle edges with respect to cation exchange.

Synthesis and characterization of poly (aniline-co-o-anisidine-co-o-toluidine) thin films in inorganic and organic supporting electrolytes

The influence of inorganic and organic supporting electrolytes on electrochemical, optical and conducting properties of poly(aniline-co-o-anisidine-co-o-toluidine), a terpolymer thin films have been investigated. Homo and terpolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of inorganic acids, viz. H2SO4, HCl, HNO3, H3PO4 and HClO4 and organic acids, viz. benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid and adipic acid at room temperature. The films were characterized by cyclic voltammetry, UV-Visible spectroscopy and conductivity measurements using four probe technique. It was observed that the current densities are strongly influenced by the size and the nature of the anion present in the electrolyte. The optical absorption spectra indicated that the conducting emeraldine salt (ES) phase formed in all the inorganic electrolytes used, whereas it formed only in oxalic acid amongst the organic acids supporting electrolytes. The conductivity of thin films was found to be greatly affected by the nature and size of the anion present in the electrolyte. In case of terpolymer (PA-co-POA-co-POT), the conductivity lies in between the conductivity of the homopolymers PA, POA and POT, irrespective of the supporting electrolyte used. Differential scanning colorimeter (DSC) study also proved the formation of terpolymer.

Electrochemical Behavior of Polyaniline, Poly(o-Anisidine) and Their Copolymer Thin Films in Inorganic and Organic Supporting Electrolytes

The influence of inorganic and organic supporting electrolytes on electrochemical, optical, and conducting properties of polyaniline, poly(o-anisidine), and poly(aniline-co-o-anisidine) thin films were investigated. Homo- and copolymer thin films were synthesized electrochemically, under cyclic voltammetric conditions in aqueous solutions of inorganic acids, viz., H2SO4, HCl, HNO3, H3PO4, and HClO4 and organic acids, viz., benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid, at room temperature. The films were characterized by cyclic voltammetry, ultraviolet (UV)–Visible spectroscopy, and conductivity measurements using four probe technique. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic supporting electrolytes used whereas, inorganic supporting electrolytes ES phase formed only with oxalic acid. It was also observed that the current density and conductivity of thin films are greatly affected by the nature and size of the anion present in the electrolyte. The formation of copolymer has also been confirmed by differential scanning calorimetry.

Ionic Solutions in the Binding Mean Spherical Approximation. Thermodynamics of Associating Electrolytes up to Very High Concentrations

A previous model, developed to describe the thermodynamic properties of associating electrolytes within the binding mean spherical approximation (BIMSA), is modified on the basis of a better representation of the pair. The ions are represented as charged hard spheres interacting through a sticky point potential, leading to the creation of pairs. In this version of the model, the species constituting the pair are allowed to have charges and sizes different from those of the free ions. New expressions for the osmotic and activity coefficients are proposed that account for these features. The equations were applied to fit the parameters in the model to osmotic data for a variety of aqueous solutions of inorganic acids, and for a base, NaOH, at 25 °C up to the highest concentrations for which data are available. In all cases, accurate representations could be obtained up to very high concentrations, such as 28 mol kg-1 for nitric acid, 45 mol kg-1 for hydrochloric acid, and 29 mol kg-1 for NaOH. The case of sulfuric acid could be treated consistently in the concentration range 0−27.7 mol kg-1 by considering the equilibrium between sulfate and bisulfate ions. In all cases, the new model represents an improvement over the previous BIMSA model.

Synthesis and characterization of conducting homopolymers and copolymers of o‐anisidine and o‐toluidine in inorganic and organic supporting electrolytes

AbstractThe influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o‐anisidine), poly(o‐toluidine), and poly(o‐anisidine‐co‐o‐toluidine) thin films was investigated. Homopolymer and copolymer thin films were synthesized electrochemically, under cyclic voltammetry conditions, in aqueous solutions of inorganic acids (H2SO4, HCl, HNO3, H3PO4, and HClO4) and organic acids (benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid) at room temperature. The films were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and conductivity measurements with a four‐probe technique. The ultraviolet–visible spectra were obtained ex situ in dimethyl sulfoxide. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic electrolytes used, whereas in organic acid supporting electrolytes, ES formed only with oxalic acid. Moreover, the current density and conductivity of the thin films was greatly affected by the nature and size of the anion present in the electrolyte. For the copolymer, the conductivity lay between the conductivity of the homopolymers, regardless of the supporting electrolyte used. The formation of the copolymer was also confirmed with differential scanning colorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2634–2642, 2003

Structural and Chemical Features of Extraction with Crown Ethers

AbstractFor Abstract see ChemInform Abstract in Full Text.

Influence of inorganic and organic supporting electrolytes on the electrochemical synthesis of polyaniline, poly( o-toluidine) and their copolymer thin films

The influence of inorganic and organic supporting electrolytes on electrochemical, optical and conducting properties of polyaniline (PA), poly( o-toluidine) (POT) and poly(aniline-co- o-toluidine) (PA–POT) thin films have been investigated. The films were synthesized electrochemically individually and then combinedly as copolymer under cyclic voltammetric conditions in aqueous solutions of inorganic acids viz. H 2SO 4, HCl, HNO 3, H 3PO 4 and HClO 4 and organic acids viz. benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid and adipic acid at room temperature. The electrosynthesized films were characterized by cyclic voltammetry, UV–visible spectroscopy and conductivity measurement using four-probe technique. It was observed that the current densities are strongly influenced by the size and the nature of the anion present in the electrolyte. The optical absorption spectra indicate the formation of the conducting emeraldine salt (ES) phase irrespective of the inorganic electrolytes, whereas it shows dependence on organic acid supporting electrolytes. Among organic acids, the formation of thin films by cyclic voltammetry and the conducting ES phase was observed only in the case of oxalic acid. It was also found that the conductivity of thin films is greatly affected by the nature and size of the anion present in the electrolyte.

Structural and Chemical Features of Extraction with Crown Ethers

Unlike linear extracting agents, in the extraction of metal salts from aqueous solutions of inorganic acids with crown ethers, the inclusion compounds, whose composition depends on several external and internal factors, go to the organic phase. The study of the molecular structure of the formed complexes by X-ray diffraction analysis showed that adducts of crown ethers with inorganic acids are host–guest complexes in which the hydroxonium ion is in the polyether macrocycle cavity. When the aqueous phase contains metal ions capable of displacing the hydroxonium ions from the macrocycle (K+, Pb2+, Hg2+, Sr2+, NH4+), complexes containing metal cations as the “guest” in the macrocycle cavity, according to X-ray diffraction data, go to the organic phase. In addition, metals forming ionic associates (AuCl4-, FeCl4-, GaCl4-) in an aqueous solution are extracted with crown ethers in accordance with the anion-exchange mechanism. A system in which traces of metals in the 2 M HNO3 +5 M HCl mixture serve as the aqueous phase was proposed for estimation of the general extraction ability of crown ethers. Such a system can be used for metal extraction via any possible mechanism. The stereochemical peculiarities of the extraction ability of crown ethers (compared to linear molecules) can be used for selective extraction and separation of metals.

Coefficient d'activité de l'acide sulfurique déterminé par titrage infrarouge

The titration of sulphuric acid by infrared spectroscopy using the attenuated total reflection (ATR) technique was made in the 0 to 14 pH range for solutions ranging from 1.89 to 0.01 M. The subtraction of the water spectrum was made using acidic, neutral, and basic waters which exhibit different spectra. The results gave the spectra of mixtures of the HSO–4 and SO2–4 ionic species in solutions. For each concentration, factor analysis (FA) sorted the spectra of the pure ionic species and gave through the multiplying factors (MF) the distribution of the species as a function of pH. This distribution is the same as that obtained from the equilibrium equations. The IR measurements gave directly the ratios of the activity coefficients of HSO–4 and SO2–4 ions. This ratio varies with the total concentration of both ions but is independent of the relative concentration. The fitting of the experimental and theoretical volumetric titration curves in the high and low pH regions gave the mean activity coefficients of the other species present in the solutions. The values obtained are comparable to those obtained by electrochemical measurements. These results show that it is possible to use IR spectroscopy to study aqueous solutions of inorganic acids from low to high concentrations.Key words : IR spectroscopy, sulfuric acid, aqueous solutions, factor analysis, ATR, principal spectra, solvation, activity coefficients, IR titration.

Coefficient d'activité de l'acide sulfurique déterminé par titrage infrarouge

The titration of sulphuric acid by infrared spectroscopy using the attenuated total reflection (ATR) technique was made in the 0 to 14 pH range for solutions ranging from 1.89 to 0.01 M. The subtraction of the water spectrum was made using acidic, neutral, and basic waters which exhibit different spectra. The results gave the spectra of mixtures of the HSO–4 and SO2–4 ionic species in solutions. For each concentration, factor analysis (FA) sorted the spectra of the pure ionic species and gave through the multiplying factors (MF) the distribution of the species as a function of pH. This distribution is the same as that obtained from the equilibrium equations. The IR measurements gave directly the ratios of the activity coefficients of HSO–4 and SO2–4 ions. This ratio varies with the total concentration of both ions but is independent of the relative concentration. The fitting of the experimental and theoretical volumetric titration curves in the high and low pH regions gave the mean activity coefficients of the other species present in the solutions. The values obtained are comparable to those obtained by electrochemical measurements. These results show that it is possible to use IR spectroscopy to study aqueous solutions of inorganic acids from low to high concentrations.Key words : IR spectroscopy, sulfuric acid, aqueous solutions, factor analysis, ATR, principal spectra, solvation, activity coefficients, IR titration.

Growth of α-PbF 2 single crystals from aqueous solutions of inorganic acids

Growth of α-PbF 2 crystals in 0.28M perchloric acid is described. The choice was based on an analysis of equilibria with the participation of fluoride ions and investigations of the solubility of lead fluoride in aqueous solutions. The enthalpy of dissolution of α-PbF 2 in 0.28M perchloric acid is 1.6 kJ/mol, which is close to the value for pure water (2.4 kJ/mol). Orthorhombic lead fluoride single crystals were grown at spontaneous crystallization by a slow cooling method in the shape of plates (3 × 3 × 0.1 mm 3) or prisms (4 × 1.5 × 0.2 mm 3), depending on the cooling rate, α-PbF 2 was grown on a seed crystal. The grown layer of about 1 mm in thickness has no visual inclusions and cracks.

ChemInform Abstract: PHOTOLYSIS OF SULFOANTHRAQUINONES AND SULFOANTHRAHYDROQUINONES IN AQUEOUS SOLUTIONS OF INORGANIC ACIDS

Chemischer InformationsdienstVolume 8, Issue 7 Preparative Organic Chemistry ChemInform Abstract: PHOTOLYSIS OF SULFOANTHRAQUINONES AND SULFOANTHRAHYDROQUINONES IN AQUEOUS SOLUTIONS OF INORGANIC ACIDS O. P. STUDZINSKII, O. P. STUDZINSKIISearch for more papers by this authorA. V. EL'TSOV, A. V. EL'TSOVSearch for more papers by this author O. P. STUDZINSKII, O. P. STUDZINSKIISearch for more papers by this authorA. V. EL'TSOV, A. V. EL'TSOVSearch for more papers by this author First published: February 15, 1977 https://doi.org/10.1002/chin.197707078Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume8, Issue7February 15, 1977 RelatedInformation

The Dissolution of Olivine in Aqueous Solutions of Inorganic Acids

Abstract The dissolution of olivine was studied in aqueous solutions of inorganic acids at temperatures of 35, 50, and 65°C in order to obtain basic information about the alteration and leaching processes in acid hot spring regions. The rates of dissolution have been determined by measuring the change in the concentrations of silica, magnesium, and the total iron leached in the solutions as a function of the time. Olivine dissolved in stirred aqueous solutions of 0.05–2n perchloric, hydrochloric, and sulphuric acids without any selective dissolution of components in the mineral. The rate at which olivine dissolved was found to be two-thirds of the reaction order with respect to the sample-powder (10–20 μ in diameter) weight (i.e., first order with respect to the surface area) and to decrease in the order of H2SO4>>HCl>HClO4. HSO4− enchanced the rate remarkably. The complexing affinity of the anions did not play an important part in the reaction with olivine powder.

A Theory of Surface Tension of Aqueous Solutions of Inorganic Acids

A Theory of Surface Tension of Aqueous Solutions of Inorganic Acids