Volume 219, Issue 12 - 12

This study aims at investigating the possibility of association of twelve aliphatic and substituted benzoic acids by physical methods, namely the UV, IR spectra, melting point and distribution method. The mechanisms of association of these acids in benzene are proved by either hydrogen bonding alone or hydrogen bonding in addition to ion-induced dipole association method. The idea of ion-induced dipole interaction on carboxylic acid system is founded here for the first time, as confirmed from the collected experimental data. The thermodynamic parameters calculated of conversion of acid polymer →  n monomer are proved to be nonspontaneous (+Δ G ), endothermic (+Δ H ) and accompanied by an increase of entropy (+Δ S ). The degree of association ( n ) of the studied carboxylic acids are found to depend on the structure or the type of the substituent group of acid and the temperature. Finally, a suitable interpretation is given for any point as supported by reference, scheme … etc.

Equations were developed for the calculation of the stoichiometric (molality scale) dissociation constants, K m , of ammonium ion in aqueous KCl solutions at 298.15 K from the thermodynamic dissociation constant, K a , of this acid and the ionic strength, I m , of the solutions. Excess KCl was used in the solutions considered so that this salt in practice determined the ionic strength of these solutions. Equations for K m were based on the single-ion activity coefficient equations of the Hückel type. Potentiometric titration data measured with a glass electrode cell were used in the estimation of the parameters for the Hückel equations. By means of the calculation method suggested in this study, K m can be obtained almost within experimental error up to I m of 1.0 mol kg −1 for KCl solutions. The K m values obtained by this method were compared to the literature results obtained from the Harned cell data of Bates and Pinching (1949) and from the concentration cell data of Everett and Wynne-Jones (1938) measured with hydrogen electrodes on cells containing two liquid junctions.

The experimentally determined activation energy of the static fatigue at elevated temperatures (creep fatigue) of specimens made of an unalloyed steel is interpreted as the energy converted into the surface (internal) energy of a crack growing in the process of fracture. In the case of iron it has been found that the activation energy amounts nearly the half of the sublimation enthalpy. In this paper the molar surface (internal) energy for solid iron is calculated from the measured activation energy of creep fatigue. This value is compared with the data of the molar surface (internal) energy of iron given by other authors.

The hydrogen bonding between methyl methacrylate and primary, secondary and tertiary alcohols has been studied by using FTIR spectroscopic method. The most likely association complex between alcohol and methyl methacrylate is 1 : 1 stoichiometric complex through the hydroxyl group of alcohol and the carbonyl group of methyl methacrylate. The formation constant of the 1 : 1 complexes has been calculated using Nash method. It appears that the primary alcohols have larger formation constant than the secondary and tertiary alcohols. The results show that the proton donating power of the alcohols decreases in the order primary > secondary > tertiary and the association constant increases with the increase in carbon chain of the alkyl group of alcohols.

Integrals being dependent on the limits only are denominated potentials. According to Hilbert’s Independence Theorem potentials are given by the limits of an action integral. Whereas the upper limit presents the actual action the lower limit concerns the least action . The action can be a constant , the least action can be zero or can be given by a finite value. As to thermodynamics the latter is true as found by Planck. According to Hilbert the path of integration must be taken along the geodesic slope as resulting from the Euler equations. Changing from dynamics to thermodynamics we change from single mass points to a system of mass points. In this case according to Caratheodory the amount as well as the direction of the geodesic slope of the components must be taken into account. As to the latter condition we consider the integrand of the action integral presented by a chain of vectors of the coordinated canonical variables. Searching according to calculus of variation for conditions that furnish a minimum value of the action integral the choice of the elliptic transcendente yields a sufficient condition. Since the latter can be reduced as shown by Legendre to three kinds of irreducible elliptic integrals the transition from the Lagrange representation into the Hamilton representation yields an irreducible action . It can be taken as compatible with the least action of Planck. Whereas the action integral presents the actual time the integrand presents the energy state. As recognized already by Gauss the reverse function must be considered to get the familiar representation.

The dielectric relaxation time (τ) of binary mixtures of different molar concentrations of pyridine (C 5 H 5 N) and nitrobenzene (C 6 H 5 NO 2 ) in benzene solution has been calculated by using standard microwave techniques and Gopala Krishna’s single frequency (9.875 GHz) concentration variational method at different temperatures (25, 30, 35 and 40 °C). It is found that the dielectric relaxation time (τ) varies non-linearly with the increasing molar concentration of pyridine in the binary mixture of pyridine and nitrobenzene. Dielectric relaxation has been found to be an activated process. Energy parameters (Δ H ε , Δ F ε , Δ S ε ) for this activated process have been calculated and compared with the parameters (Δ H η , Δ F η , Δ S η ) of viscous flow process. Based upon above results solute–solvent and solute–solute molecular associations have been proposed.

Fermat’s principle of least time and Ostwald’s law of intermediate stages are postulates concerning the physical processes that deal with light and heat energy flows, respectively. A comparative analysis of these processes shows that there is a close analogy between them. This suggests that the principle of least time can be applied to phase transitions of first kind concerned Ostwald’s law. This supposition has been proven using the Maxwell–Boltzmann distribution law and an assumed correlation between two parameters of solids (heat conductivity and activation energy of molecules). Thus, a modification of Fermat’s principle is obtained, which can be named Fermat–Ostwald principle.