Quantitative Structure-Property Relationship: X. General Form of the Structure-Property Relationship and Its Use for Estimating Boiling Points of Saturated Hydrocarbons

A general form of the structure-property relationship was obtained, corresponding to the most general definition of a property and serving as a basis for constructing approximate structure-property relationships. The potential and limitations of this approach were demonstrated by the example of estimation of the boiling points of various saturated hydrocarbons.     

Quantitative structure-property relationship: XXVII. Estimation of the free energy of formation of host-guest complexes of α-cyclodextrin with benzene derivatives

A structure-property relationship was used to estimate the free energy of formation of host-guest complexes of α-cyclodextrin with monosubstituted benzene and phenol derivatives and with symmetrical 1,4-disubstituted benzene derivatives, in which various nonvalent interactions (hydrophobic, van der Waals, donor-acceptor) play a significant role. The calculated values are well consistent with the experiment.     

Quantitative Structure-Property Relationship: XIII. Properties of Aliphatic Alcohols

A simple quantitative structure-property relationship was used to calculate a set of properties of aliphatic alcohols including the boiling point; enthalpy of vaporization; heat capacity of liquids at constant pressure; entropy, enthalpy, and free energy of formation; free energy of transfer from the gas phase to water; distribution factor in the octanol-water system; dielectric constant; surface tension; viscosity; thermal conductivity; diamagnetic susceptibility; ionization potential; self-association index; distribution factor between the gas and hexadecane; distribution factor between water and dodecyl sulfate mixelles; solubility of HCl in alcohols; and solvatochromic parameter. The rate constants, activation entropies, and activation energies of the Menshutkin reaction in alcohols were also calculated. The calculated values are in good agreement with the experimental data. The suggested relationship well reproduces the proton affinites of a series of alcohols calculated by rigorous methods.     

Application of the Bjerrum function to the potentiometric tritration of aluminum by fluoride ions

The theoretical grounds and analytical characteristics of two analytical methods, titration to a given potential and the linearized graph method, are compared using the titration of aluminum by fluoride ions in the presence of a LaF₃ electrode as an example. It is shown that there is no fundamental difference between these two methods. The linearized graph method is simpler and more accurate than the titration to a given potential. An equation is proposed for processing the results obtained using the linearized graph. This equation eliminates systematic errors due to the retarded kinetics of complexation.     

Quantitative Structure-Property Relationship: XIV. Properties of Derivatives of Saturated Hydrocarbons and Benzene,Containing Several Polar Groups

The previously suggested quantitative structure-property relationship was applied to estimate the properties of derivatives of saturated hydrocarbons and benzene, containing several polar groups. The boiling points, logP values (where P is the distribution factor in the octanol-water system), and solvatochromic parameters were calculated for a series of polyhydric alcohols, polyphenols, and isoelectronic chloro derivatives of saturated hydrocarbons and benzene. The calculated values are in good agreement with the experiment. A satisfactory correlation between these properties allows in some cases estimation of properties using a quantitative property-property relationship instead of a structure-property relationship.     

New liquid crystal derivatives of thiazole

2-(4-Alkoxybenzylidenamino)-4-(4-nitrophenoxy)thiazoles, which possess monotropic mesomorphism of the nematic type over the range 68–160°C, have been synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 546–548, April, 1996.     

Phase Diagrams of Semicrystalline Polymer–Crystalline Substances: Polyolefins–1,2,4,5-Tetrachlorobenzene

The full phase diagrams of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and isotactic polypropylene (i-PP) mixtures with 1,2,4,5-tetrachlorobenzene (TeCB), including the solubility curve of TeCB in a solid polymer, were constructed by an optical method. The diagrams contain a eutectic point that corresponds to the situation when the crystallization of TeCB out of its solution in a polyolefin is accompanied by the crystallization of monomer units of the macromolecules. As a result, the polymer acquires a gel structure with crystallites as crosslinks and amorphous regions saturated with TeCB. It is demonstrated that the eutectic point position on the phase diagram can be used for ranking polymers with respect to their thermodynamic affinity to a solvent. For the studied systems, the affinity to TeCB was decreased in the order i-PP, HDPE, and LDPE. Direct experimental evidence was obtained that TeCB crystals can be dissolved in a solid polymer via a vapor phase mechanism, which leads to the polymer amorphization.