Solutions Of Ammonium Salts Research Articles

Viscous flow in aqueous solution of quaternary ammonium salts: high concentration range

By introducing the condition that the viscosity of solutions η → η 0, the viscosity of the solvent as the concentration of the salt N → 0, we have recast Angell's equation in the following form, ln η rel = kN/[ N o( N o  N)]. This equation has been found to represent satisfactorily the viscosity behaviour of quaternary ammonium halides in aqueous solution up to high concentration and the values of N 0, the hypothetical concentration at which the solution becomes a glass, agree with those obtained from Angell's equation. The relationship with Vand's equation of fluidity is also discussed.

Stabilization of the ternary complex EF-Tu.GTP.valyl-tRNA val by ammonium salts

In a search for crystallizing conditions for the ternary complex EF-Tu.GTP.valyl-tRNAval, the influence of various salts on its stability has been examined by measuring the rate of deacylation of the aminoacyl-tRNA in the complex. The most striking result is the general higher stability in solutions of ammonium salts and, in particular, the enhancement of this effect by sulphate and citrate. Thus sodium sulphate and citrate lead to destabilization of the complex, as expected from conventional considerations of adding salt, whereas the corresponding ammonium salts stabilize the complex as shown, for example, by an increase in the half-life of the valyl-tRNAval in the complex from about 20 hours to at least 300 hours in the presence of 1.2 M ammonium sulphate. These results suggest that ammonium sulphate and ammonium citrate might be very suitable precipitants for crystallization studies of the ternary complex.

Effect of cation size on the enthalpy of dilution of alkali-metal salts of carboxymethylcellulose

The intermediate and integral enthalpies of dilution of aqueous solutions of lithium, sodium, potassium, ammonium and caesium salts of carboxymethylcellulose have been measured at 25 °C. Constant values for the intermediate enthalpies of dilution are obtained with the lithium and sodium salts within the concentration range investigated, but the potassium, ammonium and caseium salts give progressively more exothermic values as the initial concentration is reduced. The integral enthalpies of dilution are in the order Li+ > Na+ K+= NH+4= Cs+. Comparison with the corresponding series of salts of polyacrylic acid and poly(styrenesulphonic acid) shows a greater similarity with the latter group of salts.

Molar volumes of ammonium chloride—ammonium salt solutions

The apparent molar volume of ammonium bromide and ammonium nitrate has been determined in various solutions of ammonium chloride at 30°C from density measurements using an hydrostatic balance. The molar volumes show a linear function of concentration. The values of NH4Br, NH4NO3 are larger in NH4Cl solutions than in pure water and this has been attributed to the increase in the interactions of NH4Br and NH4NO3 with NH4Cl. The mean apparent molar volume of NH4Br−NH4Cl and NH4NO3−NH4Cl solutions have also been estimated directly from density measurements as well as from pure water data using Young's rule. The deviations are approximately studied as excess volume of mixing of NH4Br and NH4NO3 with NH4Cl.

Effect of ethacrynic acid on the permeability of the mitochondrial membrane in rat liver mitochondria

The effects of the diuretic agent ethacrynic acid on some mitochondrial reactions have been investigated using rat liver mitochondria. Ethacrynic acid inhibits the oxidation of succinate in a competitive manner, whereas non-competitive inhibition by ethacrynic acid is found on the translocation of cis-aconitate and oxoglutarate as measured by fluorimetry. Ethacrynic acid causes mitochondrial swelling in solution of ammonium salts of several “non-penetrant” anions. Swelling depends on the reactivity of ethacrynic acid with thiols of the mitochondrial membrane. These results suggest a general ability of ethacrynic acid to inhibit mitochondrial carriers and influence the membrane conformation and permeability. These conclusions are discussed in the light of the effect of this diuretic agent on mitochondrial and cellular activity and of the location of thiols in the carriers of citric cycle intermediates.

23Na relaxation in polyelectrolyte solutions

In order to get a better insight into the layer of “condensed” counterions, 23Na relaxation measurements have been carried out upon progressive addition of ClNa to a solution of the tetramethyl ammonium salt of polyacrylic acid. They show that for r = Na +/TMA + < 1, the relaxation rate is a fast decreasing function of r.

Diffusivities and Solubilities of NH&lt;SUB&gt;3&lt;/SUB&gt; Gas in Aqueous Solutions of Ammonium Salts

Diffusivities and Solubilities of NH&lt;SUB&gt;3&lt;/SUB&gt; Gas in Aqueous Solutions of Ammonium Salts

Improvement of Carob Pods as Feed by Solid‐substrate Fermentation

Chopped carob pods were autoclaved in an ammonium salt solution. The solution was absorbed by the pods during autoclaving. The material was inoculated with either Rhizopus oligosporus or Monascus ruber and incubated for 3 d at 30 °C. The growing mycelium penetrated the particles to form a cake‐like structure containing ca. 7% protein. The fermentation product contained 73–83% of the original carob sugars, whereas the amount of tannins was considerably lower than in the pods.

Study of combined electroreflectance and double layer effects at lead electrodes

Reflectance changes at lead electrodes have been measured as a function of surface charge at 45° and 70° angles of incidence using solutions of sodium fluoride and quaternary ammonium salts. These solutions were chosen so as to provide quite different composition for the inner layer at the metal/solution interface, and hence different optical contributions there from. Linear reflectance-surface charge relation has been observed for NaF solutions only at a number of wavelengths. The optical effects from the inner layer has been recognized but could not be separated out from the main er effect by comparative measurements at two angles of incidence. This has been rationalized on the basis of similar variation of the er effect and the optical effect from the double-layer as a function of angle of incidence of light.

Preparation of an inner membrane-matrix fraction from yeast mitochondria

Treatment of yeast mitochondria with digitonin was used in order to prepare an inner membrane-matrix fraction preserving its permeability properties. The incubation time of mitochondria with digitonin was an essential parameter for the selective solubilization of the outer membrane. The incubation of mitochondria for l min at different concentrations of digitonin led to a three-step release of mitochondrial enzymes: (a) at low concentrations of digitonin, adenylate kinase was released; (b) higher concentrations were required to solubilize kynurenine hydroxylase, an outer membrane marker; (c) inner membrane markers (succinate dehydrogenase and oligomycin-sensitive adenosine triphosphatase) and matrix markers (fumarase and isocitrate dehydrogenase) were significantly released at concentrations of digitonin higher than 0.4 mg/mg of protein. The electron microscopic aspects of yeast mitoplasts (inner membrane-matrix fraction obtained by treatment with 0.4 mg of digitonin) showed an orthodox and a twisted configuration. These new organelles retained respiratory control when assayed with ethanol as the substrate. Their selective permeability properties were preserved as shown by isoosmotic swelling in potassium or ammonium salt solutions.

ABSORPTION OF NITROGEN OXIDES WITH AMMONIUM SALTS

Abstract Absorptions of an equimolar mixture of NO and NO2 in an aqueous solution of ammonium salts and with a cation-exchange resin substituted by ammonium ion were investigated by a flow method. Ammonium salts such as phosphate, benzoate, and oxalate were found effective for the removal of nitrogen oxides. Effects of temperature and time of contact were examined.

Metastable equilibria in the system copper sulphidesulphuric acidammoniawater at 25°C

Potential-pH metastable equilibria diagrams for the system Cu 2− x SH 2SO 4NH 3H 2O at 25°C have been elaborated. New equations describing the potential of the nonstoichiometric copper sulphide electrode are presented. Potentiometric measurements were carried out on electrodes made of synthetic deficient chalcocite in solution of ammoniacal ammonium salts with a variable concentration of Cu(II) ions, free ammonia and environmental pH. Good agreement was found between the obtained experimental results and the relations established thermodynamically. On the basis of potentiometric measurements carried out in acidic solutions the value of the Gibbs standard free energy of the formation of djurleite Cu 1.965S was determined as − 20.33 kcal/mol.

THE HYDRATION OF AROMATIC QUATERNARY AMMONIUM SALTS DEDUCED FROM THE MEASUREMENTS OF DENSITY AND NMR

The densities of aqueous solutions of aromatic quaternary ammonium salts have been measured at 6°, 15°, 25°, 35° and 45°C. The infinite dilution molal expansibility _??_, has been calculated from the partial molal volume _??_, at various temperatures. The ∂_??_/∂t values are found to be positive for all of the salts. The ∂2_??_/∂t2 values are found to be zero for all of the salts except TMPA+ with the negative one. This negative value suggests that the TMPA+ is a structure breaker.The experimental Sv values for all of the salts do not agree with that predicted by the Debye-Huckel theory. This deviation of Sv is interpreted by the influence of the salts on the water structure on the basis of the correlation with the water proton chemical shifts of the salt solutions.

PROTON CHEMICAL SHIFT OF WATER IN QUATERNARY AMMONIUM SALT-ELECTROLYTE MIXTURES

The proton chemical shifts of water were measured in solutions of mixtures of quaternary ammonium salts (Me4NCl and Me3BeNCl) and metal chlorides (LiCl, KCl, CsCl and MgCl2) as a function of the metal chloride molality. Two additivity rules were examined: (1) eq. (1) which evaluates the contribution of the metal salt by the actual concentration in the mixture solution. where Δν′_??_ means the difference between the chemical shifts of the mixture solution and the reference ammonium salt solution, a1, b1 are the constants, x1 is the mole fraction of the metal chloride and mt is the molality of the salt mixture in solution, and (2) eq. (2) which evaluates the metal salt contribution per mole by the total concentration of the salt mixture. The difference, Δν′_??_, for the mixtures including Me4NCl was explained by rule (2), but not by rule (1). On the other hand, the difference for the mixtures including Me3BeNCl was not accounted for by either rule. We suggest that this divergence may be related to Me3BeN+-Me3BeN+ interaction in the relevant solutions.

Conductance‐Viscosity Studies on Some Moderately Concentrated Nonaqueous Electrolyte Solutions from −50° to 125°C: II . Solutions of ,, and in Propylene Carbonate

Matching conductance, viscosity, and density data at 25° intervals between −50° and 125°C have been determined and analyzed for moderately concentrated solutions of three quaternary ammonium halides in propylene carbonate. Detailed results are presented for the fitting of experimental data as functions of molal concentration and temperature to appropriate equations by computer least squares procedures. Calculated results related to moles of solvent displaced per mole of solute and also apparent molal volumes indicate the lack of significant ion‐solvent interactions in the solutions of the quaternary ammonium salts in propylene carbonate. Additionally, conductance‐viscosity products and activation energies of viscous flow and conductance have been calculated and discussed. Throughout the broadly varying experimental conditions over the 175°C range, the conductances of the three salts have been found to be fairly closely proportional to the fluidity, or reciprocal of the viscosity, of the medium.

Effects of microscopic and macroscopic viscosity on the rate of renaturation of DNA.

AbstractThe effect of solvent viscosity on DNA renaturation rates has been investigated as a function of temperature for a number of solvent systems. The results are all consistent with a microscopic viscosity limitation of the rate determining step. Rates of renaturation in perchlorate and quaternary ammonium salt solutions are also discussed. Increasing the macroscopic viscosity with dissolved neutral or anionic polymers increases, rather than decreases, renaturation rates due to the excluded volume of the dissolved polymers.

Differential capacitance of polycrystalline zinc: Part I. Effect of pH and ammonium ions

Summary Differential capacity measurements have been made using a polished polycrystalline zinc electrode in aqueous solutions of NaClO 4 and NH 4 ClO 4 at various pH's. In solutions of NaClO 4 at pH values >3.4 strong OH − ion interaction with the electrode is confirmed. In NH 4 ClO 4 solutions this interaction is not appreciable until the pH is raised to about 8.6. This is thought to be due to the weakly acidic nature of the ammonium ion, which produces an increase in the local acidity at the zinc surface. To a first approximation the differential capacitance of the zinc electrode in neutral solutions of ammonium salts can be identified with the double layer capacity, since the characteristics of the electrode in the additional presence of tetrabutylammonium cations are very similar to those observed for zinc single crystals. This paper therefore re-emphasises the importance of solution pH in the determination of the double layer capacity of polished polycrystalline zinc.

Formation of solid solutions of ammonium and cesium salts by explosion

Solid solutions of NH4Cl-CsCl and NH4I-CsI were obtained by the explosion compression method. The theory was expressed that the synthesis of the solutions took place at the time of the action of the high pressure.

15N chemical shifts in concentrated aqueous solutions of ammonium salts

15N n.m.r. spectra have been recorded from salts of 15N enriched ammonium ions in aqueous solution. Shifts of the resonance frequency have been attributed to direct interaction between the ammonium and its counter ion in solution.

Reduction of α-ω dibromoalkanes on aluminium and mercury cathodes

1,3-Dibromopropane and 1,4-dibromobutane have each been reduced from non-aqueous solutions of quaternary ammonium salts on cathodes of mercury and aluminium. Product analysis and kinetic measurements have shown that reduction on mercury proceeds through adsorbed radicals whereas on aluminium products are explained in terms of free radical reactions initiated by solvated electrons. Products on mercury include solid organomercury polymer and dibutylmercury from dibromobutane and by contrast cyclopropane and propane from dibromopropane. The difference is explained in terms of the kinetic facility of formation of cyclopropane and the greater stability of the adsorbed butyl diradical relative to its propyl analogue. Products on aluminium cathodes include higher bromides and dibromides.