scholarly journals ON GUAIACOL SOLUTIONS

1934 ◽  
Vol 17 (4) ◽  
pp. 563-576 ◽  
Author(s):  
Theodore Shedlovsky ◽  
Herbert H. Uhlig
Keyword(s):  
Electrical Conductivity ◽  
Partition Coefficients ◽  
Dissociation Constants ◽  
Dielectric Constants ◽  
Weak Electrolytes ◽  
Strong Electrolytes ◽  
Theoretical Considerations ◽  
Sodium And Potassium

1. Measurements are reported on the distribution of sodium and potassium guaiacolates between guaiacol and water at 25°C. 2. The variation of the partition coefficients with the concentration is explained with the aid of the Debye-Hückel interionic attraction theory and the assumption that the salts are strong electrolytes in water and weak electrolytes in guaiacol. 3. The dissociation constants of sodium and potassium guaiacolates in guaiacol previously computed from electrical conductivity determinations are shown to be in agreement with the corresponding values obtained from the distribution measurements. 4. From theoretical considerations an equation is derived with which it is possible to predict the magnitude of the limiting partition coefficients from the dielectric constants of the solvents, the size of the solute ions, and the temperature.

scholarly journals ON GUAIACOL SOLUTIONS

1934 ◽  
Vol 17 (4) ◽  
pp. 549-561 ◽  
Author(s):  
Theodore Shedlovsky ◽  
Herbert H. Uhlig
Keyword(s):  
Electrical Conductivity ◽  
Dissociation Constants ◽  
Dielectric Constants ◽  
Conductivity Measurements ◽  
Ionic Equilibrium ◽  
Weak Electrolytes ◽  
Ionic Mobilities ◽  
Water Saturated ◽  
Limiting Equivalent Conductances ◽  
Sodium And Potassium

1. Measurements on the densities, viscosities, dielectric constants, and specific conductances of pure anhydrous and water-saturated guaiacol at 25°C. are reported. 2. The solubility of water in guaiacol at 25°C., and its effect on the electrical conductivity of a sodium guaiacolate solution is given. 3. Electrical conductivity measurements are reported on solutions of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C. 4. The decrease of electrical conductivity with increasing concentration for these salts is explained on the basis of an ionic equilibrium combined with the interionic attraction theory of Debye and Hückel. 5. The limiting equivalent conductances of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C., the corresponding limiting ionic mobilities, and the dissociation constants are computed from the conductivity measurements. The salts are found to be weak electrolytes with dissociation constants of the order of 5 x 10–6.

scholarly journals Investigation of temperature effect on the electrical conductivity of alcohol solutionssodium and potassium alcoholates

2020 ◽  
Vol 61 (1) ◽  
pp. 81-85
Author(s):  
Vera A. Petrukhina ◽  
◽  
Pavel I. Fedorov ◽  
Ksenia A. Konnova ◽  
Maria V. Yakimova ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Temperature Dependence ◽  
Isopropyl Alcohol ◽  
Effect Of Temperature ◽  
Inorganic Salts ◽  
Equivalent Conductivity ◽  
Solutions Of Electrolytes ◽  
Weak Electrolytes ◽  
Sodium And Potassium

Earlier, we studied the electrical conductivity of inorganic salts in a number of alcohols (ethanol, propanol-2, and butanol-1) at room temperature and found that alcoholic solutions of inorganic salts are weak electrolytes. It is known that an increase in the temperature of salt solutions leads to an increase in electrical conductivity due to an increase in the mobility of their ions in the solvent medium. To study the temperature dependence of the electrical conductivity of aqueous solutions of electrolytes, we proposed an approach based on the study of the effect of temperature on the equivalent electrical conductivity of solutions at infinite dilution λ∞. Using this approach, we studied the electrical conductivity of aqueous solutions of a number inorganic salts (nitrates, acetates, and phosphates), carboxylic acids, and amino acids as a function of temperature. It was found that for these solutions the dependence λ∞(Т) is described by the exponential Arrhenius equation λ∞ = Аexp(-E/(RT)). This equation was used to describe the temperature dependence of the ultimate equivalent conductivity for solutions of a number of inorganic salts (calcium and nitrate calcium, cadmium, lithium and potassium iodides, chloride, iodide and ammonium nitrate, silver nitrate and sodium bromide) in ethanol. This article investigated and demonstrated the possibility of describing the experimental data λ∞(Т) for solutions of ethylates, propylates and isopropylates of sodium and potassium in the corresponding alcohols (ethylates in ethanol, propylates in propanol, isopropylates in isopropyl alcohol) using the same equation.

scholarly journals THE EFFECT OF ISOELECTRIC AMINO ACIDS ON THE pH+ OF A PHOSPHATE BUFFER SOLUTION

1930 ◽  
Vol 13 (5) ◽  
pp. 509-527 ◽  
Author(s):  
Henry Borsook ◽  
Douglas A. MacFadyen
Keyword(s):  
Amino Acids ◽  
Dissociation Constants ◽  
Pure Water ◽  
Phosphate Buffer Solution ◽  
Dielectric Constants ◽  
Buffer Solution ◽  
Strong Electrolytes ◽  
Classical Conception ◽  
Zwitter Ion ◽  
Acetic Acids

The relative merits of the classical conception and of the Zwitter Ion conception of the dissociation of amphoteric electrolytes are discussed, and the following data are presented which confirm the Zwitter Ion hypothesis of Bjerrum, and which are not in accord with the classical view. 1. Amino acids in the isoelectric form resemble strong electrolytes in that they contribute to the ionic strength of the solution. 2. The dielectric constants of aqueous solutions of amino acids, like those of solutions of strong electrolytes greater than 0.02 normal, are considerably greater than that of pure water. 3. The magnitude of the dissociation constants of substituted acetic acids and of glycine, are more easily accounted for with the Zwitter Ion than with the classical conception.

Biologically Important Physicochemical Properties of Some Cephalosporins

1992 ◽  
Vol 57 (8) ◽  
pp. 1739-1746
Author(s):  
Katarína Škvareninová ◽  
Štefan Baláž ◽  
Ernest Šturdík ◽  
Miroslav Veverka ◽  
Jana Adamcová ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Partition Coefficients ◽  
Dissociation Constants ◽  
Transport Rate ◽  
Hydrolysis Rate ◽  
Antibacterial Effects ◽  
Oh Groups ◽  
Non Linear Equation ◽  
Cell Components ◽  
The Relationship

In the series of cephalosporin derivatives, consisting of eight 7-(R1-CH2-CO-NH)cephalosporanic acids and of seven analogical compounds with 3-acetoxymethyl replaced by 3-CH3, physicochemical properties, which are expected to play a role in their antibacterial effects (the transport rate parameters and partition coefficients in the systems 1-octanol-water and 1-octanol-buffer, dissociation constants of the 4-carboxyl group, reactivity towards L-glutathione imitating the nucleophilic groups of the cell components and hydrolysis rate parameters), were determined. Linear dependences were observed between the partition coefficients and the π-constants of the varying substituents as well as between reactivity towards SH-groups of L-glutathione and OH-groups. The relationship between the transport rate parameters and partition coefficients, both measured in buffered as well as non-buffered system, was described by a common non-linear equation.

Spectrophotometric study of the effect of sodium dodecyl sulphate on the acid-base behaviour of 4-(2-pyridylazo)-resorcinol

1991 ◽  
Vol 56 (4) ◽  
pp. 785-795 ◽  
Author(s):  
Jiří Bílý ◽  
Ludmila Čermáková ◽  
Jiří Knapp
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Sodium Dodecyl Sulphate ◽  
Azo Dye ◽  
Dissociation Constants ◽  
Sodium Dodecyl ◽  
Spectrophotometric Study ◽  
Acid Base ◽  
Strong Electrolytes ◽  
The Given

The values of the apparent dissociation constants of the azo dye 4-(2-pyridylazo)-resorcinol (PAR) have been found in the presence of sub- and supercritical concentrations of the anionogenic tenside sodium dodecyl sulphate (SDS) and the effects of the strong electrolytes NaCl and NaNO3 were also evaluated. In both electrolytes, the pKan values initially are independent of the SDS concentration and then increase. Spectrophotometric and surface tension measurements were employed to determine the critical micelle concentration (cmc) of SDS alone and in the presence of PAR and the given electrolytes. The determined cmc values were in the range 0.20–3.02 mmol l-1 and dependent on the type and concentration of the particular additive.

On the quantitative relations between structure and antiaggregation activity of ω-aryl-ω-oxoalkanoic acids

1986 ◽  
Vol 51 (11) ◽  
pp. 2617-2625 ◽  
Author(s):  
Miroslav Kuchař ◽  
Bohumila Brunová ◽  
Jaroslava Grimová ◽  
Václav Rejholec ◽  
Václav Čepelák
Keyword(s):  
Partition Coefficients ◽  
Dissociation Constants ◽  
Inhibitory Effect ◽  
Partition Chromatography ◽  
Linear Quadratic ◽  
Marked Influence ◽  
Methyl Group ◽  
Retention Characteristics ◽  
Anti Inflammatory

A series of ω-aryl-ω-oxoalkanoic acids, I-IV, has been prepared and investigated for dissociation constants in 80% methylcellosolve, retention characteristics in thin-layer partition chromatography and partition coefficients P in the system octanol-water. Also evaluated were their anti-inflammatory efficacy and inhibitory effect on the platelet aggregation induced by collagen. Analysing the relations between structure and antiaggregation effect, we obtained a non-linear, quadratic dependence of this effect on lipophilicity, the optimum being at log P = 3. The antiaggregation effect increased with shortening the chain between the carbonyl and the carboxyl, and with increasing acidity. It was also diminished by the presence of a methyl group on the interlinking chain. To assess the role of lipophilicity we used the RM values of partition chromatography. The relation between anti-inflammatory efficacy and structure was assessed only qualitatively. In this aspect, too, the nature of the chain between the carbonyl and carboxyl proved to have a marked influence. The anti-inflammatory activity proved considerably enhanced by the presence of another aromatic ring in ω-oxoalkanoic acids derived from biphenyl.

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