NaClO4 Aqueous Solution Research Articles

Complex formation of beryllium(II) with salicylate and hydroxide ions in 1 mol dm–3sodium perchlorate aqueous solution at 25 °C

The complex formation of Be2+ with salicylate (L2–) and hydroxide ions was investigated at 25 °C in 1 mol dm–3 NaClO4 by potentiometry using a glass electrode. The e.m.f. measurements were performed under the conditions 2.7 ⩽–log [H+]⩽ 8, 0.002 ⩽cM⩽ 0.01 mol dm–3, 0.002 ⩽cL⩽ 0.015 mol dm–3, and 1 ⩽cL/cM⩽ 7, where cM, and cL, denote the total concentrations of BeII and salicylic acid, respectively. The e.m.f. data were explained with the three major species [Be(HL)L]–, [BeL], and [BeL2]2– and at least one or even all of the four minor species [Be(HL)]+, [Be(HL)2], [Be(OH)L]–, and [Be3(OH)3L3]3–. The hydrolytic reactions of BeII in 1 mol dm–3 NaClO4, data on which were used for the analysis of the above beryllium(II)–salicylate-hydroxide system, were also studied by separate potentiometric titrations. It was found that [Be2(OH)]3+, [Be3(OH)3]3+ and [Be6(OH)8]4+ occur in 1 mol dm–3 NaClO4 aqueous solution.

Electrochemical Properties of Electropolymerized Poly(1-pyrenamine) Films

Abstract The electropolymerization of 1-pyrenamine (PA) in an acetonitrile solution led to the polymeric film formation on electrode surfaces. The chemical, spectroscopic, electrical and electrochemical characterization of the resulting poly(1-pyrenamine) (PPA) films was carried out. The number-average molecular weight of the PPA film, measured by gel permeation chromatography, was 1.8×103, corresponding to the degree of the polymerization of ca. 8. The PPA films were polymer-anion composites which contained ca. 0.3 anions (e.g., BF4−) per repeating aromatic unit, which is considered to be composed of three PA molecules. The oxidized form of the PPA film displayed the ESR response. The g factor was 2.0082 and the concentration of radical in the PPA film was determined to be 4.8×1019 e−g−1. The conductivities of the PPA films in the dry state at 300 K were in the range 10−11–10−10 S cm−1. The PPA film was electroactive in an aqueous solution as well as in a non-aqueous solution. The cyclic voltammetric responses depended on pH of aqueous solutions and supporting electrolyte in non-aqueous solutions. The thickness(φ) of the PPA film and the surface concentration(Γ) of the electroactive site in the PPA film were proportional to the amount (Q) of the charge passed during the electrolysis (when Q<ca. 120 mC cm−2). The volume concentrations of the electroactive site were 9.7×10−4 and 1.7×10−3 mol cm−3 for the PPA films prepared in the NaClO4 and TBABF4 (tetrabutylammonium tetrafluoroborate) electrolytes, respectively. From the normal pulse voltammetric, potential-step chronoamperometric and potential-step chronocoulometric experiments of the PPA films in a 0.2 M NaClO4 aqueous solution (pH 1.0), the effective apparent diffusion coefficient (Dapp) for the diffusion-like charge transport within the PPA films, and the standard rate constant (k°) and anodic transfer coefficient (αa) of the heterogeneous electron-transfer reaction between the In2O3 electrode and the electroactive site in the PPA film were estimated to be (1.5±0.5)×10−10 cm2 s−1, (1.9±0.4)×10−5 cm s−1 and 0.67±0.03, respectively.

Near-infrared spectra of water and aqueous electrolyte solutions at high pressures

The near-infrared spectra (9500 to 11000 cm−1) of pure water and aqueous solutions of alkali halides, MgCl2, NaClO4, and R4NBr were measured at temperatures between 10 and 55°C and pressures up to 500 MPa. From the analysis of the absorption spectra the following conclusions are drawn. (1) The ice I-like open structure is destroyed and the packed structure is formed as the pressure is increased. (2) The open structure of water is destroyed by the addition of alkali halides and MgCl2 and water molecules are restricted around the ions by ion-dipole interactions. This results in a loosening of the O−H bond. (3) The perchlorate ion destroys the open structure of water and the ion-dipole interaction with water is insignificant. (4) The Bu4N+ ion forms water structure around the ion similar to that of the clathrate open structure.

Partition of Carboxylic Acids between Benzene and Aqueous Solution as Considered from the Regular Solution Theory

Abstract The partition of carboxylic acids between benzene and 0.1 mol dm−3(H,Na)ClO4 aqueous solution has been studied at 25 °C. Carboxylic acids used include acetic, propanoic, butanoic, pentanoic, hexanoic, and decanoic acids. The hydration of monomeric acids in benzene being taken into account, the hydration-corrected partition constant has been calculated. The effect of the chain length on the partition is accounted for with the aid of the newly estimated solubility parameters and empirical binary coefficients. Applicability of the empirical solubility parameter of water (35.89 J1⁄2 cm−3⁄2) has also been discussed.

Infrared Absorption of Concentrated Aqueous NaClO4 Solutions to High Pressures and Temperatures

The infrared absorption of the O-D stretching fundamental of HDO in concentrated aqueous (HDO/H2O)NaClO4 solutions up to 20 mole% salt has been measured. The data for the wave-number of maximum absorption, ν̅(max), and for the integrated molar absorptivity B up to pressures and temperatures of 2800 bar and 250 °C, respectively, demonstrate the importance of non-hydrogen-bonded interactions in aqueous perchlorate solutions. A non-continuous dis­tribution of the states of water molecules is clearly evident from the experimental spectra. A band separation using three Gaussian components proves the close similarity between the high-pressure high-temperature vibrational O-D infrared spectra of aqueous perchlorate solutions and the O-D Raman spectra of water and aqueous solutions. Results of the band separation together with literature Raman data provide some evidence that a transition from “water-like” to “melt-like” behaviour occurs in a fairly narrow concentra­tion region between 10 and 15 mole% salt.

Raman Spectra of Aqueous NaClO4 and NaBF4 Solutions

AbstractThe OD stretching vibration band in Raman spectra of liquid HOD containing ClO4− or BF4− ions is splitted into two components. The higher frequency band vw is assigned to ODw groups which are weakly H‐bonded to neighbouring anions (A): ODw = (OD... A). In Raman spectra of fully deuterated aqueous NaClO4 or NaBF4 solutions the vw band is splitted once again. The higher frequency band v3, wb is attached to the partially antisymmetric stretching vibration of unsymmetrically H‐bonded D2O molecules with a weak H‐bond at one OD group and a strong H‐bond at the other OD group (= bDODw). The lower frequency band must be assigned to the symmetric stretching vibration of D2O weakly H‐bonded to anions with both OD groups (= wDODw). The bands were separated into Gaussian‐Lorentzian product functions. The OD and D2O concentration were calculated from the band areas.

Extraction of some metals into solutions of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 in freon 113

The partition of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (HA) between aqueous solutions of HClO4 and NaClO4, ionic strength 0.1, and Freon 113 or its 2 : 1 mixture with benzene was studied. The logarithms of the HA distribution constants are 2.84 ± 0.10 and 3.39 ± 0.15 for the two organic phases, respectively. The extraction curves of cerium(III) and europium(III) revealed that in dependence on the pH of the aqueous phase, the metals are transferred into the organic phase in the form of the MA3 complexes (M = Ce, Eu). The stability constants of the complexes MAn in the aqueous phase were determined along with their distribution and extraction constants. For cobalt, zinc, and hafnium, a part of the extraction curves could only be studied, only the extraction constants were therefore determined. The sparing solubility of HA in Freon 113 can be circumvented by using a Freon-benzene mixture 2 : 1, which is still practically incombustible.

The Temperature Dependence of the Solubilities of 1-Phenyl-1,3-butanedione and 4,4,4-Trifluoro-1-phenyl-1,3-butanedione in Water and Aqueous Electrolyte Solutions

Abstract The temperature dependence of the solubilities of 1-phenyl-1,3-butanedione (benzoylacetone) and 4,4,4-tri-fluoro-1-phenyl-1,3-butanedione (benzoyltrifluoroacetone) in water and in 1.0 mol l−1 aqueous solutions of HClO4, HCl, NaClO4, KCl, NaBr, NaCl, BaCl2, and Na2SO4 was determined over the temperature ranges of 20 to 45°C for benzoylacetone and of 15 to 30°C for benzoyltrifluoroacetone. From these data, the thermodynamic quantities associated with the dissolution in water and with the transfer from water to the aqueous electrolyt solutions were estimated. Both the enthalpy and the entropy of solution of benzoyltrifluoroacetone in water were much smaller than those for benzoylacetone. This was interpreted by assuming a higher hydrophobic hydration for the less polar benzoyltrifluoroacetone. The thermodynamic quantities of the transfer of benzoyltrifluoroacetone from water to the aqueous perchloric acid solution showed characteristic features compared with those of the other electrolyte solutions. The overall salt effect on the dissolution of benzoylacetone and benzoyltrifluoroacetone is discussed in terms of the change in the thermodynamic quantities.

Heat capacities of aqueous perchloric acid and sodium perchlorate at 298�K: ?C p o of ionization of water

We have used a Picker flow calorimeter for measurements leading to apparent molal heat capacities of dilute aqueous solutions of HClO4 and NaClO4 at 298°K. Results have been used to derive φ c ° =−27.1J-°K−1-mole−1 for HClO4 (aq.), φ c ° =15.2J-°K−1-mole−1 for NaClO4 (aq.), and ΔCp=−213.8J-°K−1-mole−1 for ionization of water.

Thermal behavior of the near ir absorption of H2O and NaClO4 aqueous solutions

The IR absorption spectrum of water and NaClO4 solutions in the 1.45 μ region was studied as a function of temperature and salt concentration. Band profile synthesis with Gaussian components shows the existence of three such components. The temperature and concentration dependence of their intensities, peak frequencies, and widths is analyzed and discussed.

Separation of hydration isomers of51CrCl3·6H2O by thin-layer chromatography and its application to the investigation of isomeric transitions occurring in the titration of these isomers with a base

A thin-layer chromatographic method was elaborated for the separation of hydration isomers of51CrCl3·6H2O. The layer consists of Dowex 50WX4 and microcrystalline cellulose. As developing solvent the aqueous solution of NaClO4 and NaCl is used. The precision of the method for the determination of the amounts of the dark-and light-green isomers is ±2 abs %., and for that of the violet isomer ±0.5 abs %. The method was used in the study of changes occurring in the aqueous solutions of pure isomers in the course of titration with NaOH or in back titration with HCl. From the results obtained it follows that the transitions of hydration isomers of CrCl3·6H2O from dark- and light-green to the violet form or the basic forms of chromium(III) chloride or chromium(III) hydroxide is irreversible in aqueous solutions.

The stimulated Raman spectrum of water and its relationship to liquid structure

Stimulated Raman spectra (SRS) of H2O, D2O, H2O–D2O mixtures, and aqueous solutions of NaClO4 have been measured using a mode-locked, stabilized Nd glass laser operating in the TEM00 mode. Spectra with relatively narrow peaks were obtained in all cases, as predicted by the first order theory of SRS. Other effects (such as multiple peaks, broadened spectra, and shifted peaks), which have been interpreted as evidence for a mixture model of water, are reconsidered, and it is argued that they are either artifacts arising from modulation by stimulation in the hydrogen bond bending region or arise from disruption of thermal equilibrium in filaments due to the high electric fields present in the focused laser beam.

Anomalies in the temperature dependence of the 1.2-? absorption of liquid water

The weakly absorbed 1.2-μ combination band of water was accurately studied as a function of temperature, in both its profile and first derivative, to obtain information on the bulk properties of liquid water. Arrhenius plots of integrated component intensity ratios showed well aligned experimental points, except for a neatly defined break occurring in the 30 to 40°C temperature interval for pure water A similar break, shifted by some 18°C towards lower temperature, was found in the case of 1M NaClO4 aqueous solutions. The breaks are tentatively assumed to result from abrupt though subtle changes involving low-frequency modes. This tentative, assumption appears independent of specific models and assignments and, although in agreement with available neutron-scattering and NMR data, needs more direct verification.

Differential capacitance of polycrystalline zinc Part II. Effect of amalgamation and tetraalkylammonium ions

Differential capacity measurements have been made in aqueous solutions of NaClO4 and in these solutions containing Pr4NCl and Bu4NBr using a polished polycrystalline zinc electrode amalgamated to three different microgram levels. It is postulated that mercury has the effect of etching the zinc surface probably by preferentially attacking the grain boundaries and this change in the physical state of the electrode influences not only the extent of adsorption of tetraalkylammonium cations but also their general adsorption characteristics. It is also suggested that amalgamation does not appreciably affect the chemical nature of the electrode since in neutral solutions strong OH− ion interaction with the surface occurs at the same potential as that for an unamalgamated electrode. This paper therefore re-emphasises the importance of the physical state of the electrode surface in the determination of the characteristic double layer capacity of solid electrodes.

Differential capacitance of polycrystalline zinc: Part II. Effect of amalgamation and tetraalkylammonium ions

Summary Differential capacity measurements have been made in aqueous solutions of NaClO4 and in these solutions containing Pr4NCl and Bu4NBr using a polished polycrystalline zinc electrode amalgamated to three different microgram levels. It is postulated that mercury has the effect of etching the zinc surface probably by preferentially attacking the grain boundaries and this change in the physical state of the electrode influences not only the extent of adsorption of tetraalkylammonium cations but also their general adsorption characteristics. It is also suggested that amalgamation does not appreciably affect the chemical nature of the electrode since in neutral solutions strong OH− ion interaction with the surface occurs at the same potential as that for an unamalgamated electrode. This paper therefore re-emphasises the importance of the physical state of the electrode surface in the determination of the characteristic double layer capacity of solid electrodes.

Vinyl polymerization by metal complexes. III. Vinyl polymerization initiated by oligoamide and cupric ion system

AbstractPolymerization of methyl methacrylate and other vinyl monomers was studied in the presence of oligoamide (ϵ‐aminocaproic acid, its dimer, trimer, tetramer, and pentamer) and cupric ion in aqueous media. The polymerization was found to be of free‐radical character and selective for the type of vinyl monomer. Carbon tetrachloride can accelerate the polymerization. The initiation mechanism of the polymerization is discussed. Spectroscopic measurements were indicative of formation of 1:1 complex between oligoamides and cupric ion in aqueous NaClO4 solution. Some chemical and physical properties of the resulting polymers were measured.

NMR Studies of Aqueous Electrolyte Solutions. III. Hydration of Sodium Perchlorate, Hydrochloric Acid, and Perchloric Acid from Temperature Effects on Proton Shifts

Proton resonance shifts of aqueous solutions of NaClO4 and HCl are measured as a function of temperature and concentration. In each case the proton spectrum consists of a single resonance line which is sensitive to both temperature and concentration. The shift is considered to be an average of the proton in its various environments; namely, bulk water and ionic hydrates. At low concentrations the total hydration numbers of NaClO4, HCl, and HClO4 are determined to be 3.0 ± 0.2, 3.4 ± 0.4, and 2.6 ± 0.4, respectively. Assignments of individual hydration numbers to H+, Na+, Cl−, and ClO4− ions are discussed.

Nuclear Magnetic Relaxation in Ionic Solution. I. Relaxation of 23Na in Aqueous Solutions of NaCl and NaClO4

The relaxation time of the nuclei of sodium ions has been measured for aqueous solutions of sodium chloride and sodium perchlorate at 25°. The longitudinal and transverse relaxation times are equal and depend on solution composition according to the rate law T1−1=17.55+0.55cNaCl+11.95cNaClO4±0.30,with T1 in seconds and cX in moles of X per liter, for single and mixed electrolyte solutions at concentrations less than 1M. Deviations from the equation are small up to 3M total concentration, and also in D2O if the coefficients are first multiplied by the ratio of solvent viscosities. The limiting value of T1 at low concentration agrees roughly with the calculation of the effect of fluctuating electric-field gradients due to reorientational Brownian motion of water molecules coordinated to the sodium ion, but there are some very uncertain factors in the calculation. The coefficients of the rate law may be related to the distance of closest approach of the ions in various ways, with the result that this distance is much smaller for Na+ClO−4 than for Na+Cl−.