Wyniki wyszukiwania - BazTech

Ograniczanie wyników

3 International Letters of Chemistry, Physics and Astronomy

3 2015

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Ultrasonic speed, density, viscosity and associated acoustical parameters of chloroform solutions of symmetric double Schiff bases at 308.15K

Gangan B. J., Parsania P. H.

International Letters of Chemistry, Physics and Astronomy

2015

Vol. 45

16--23

The density, viscosity and ultrasonic speed (2MHz) of chloroform and symmetric double Schiff bases have been investigated at 308.15K. Various acoustical parameters such as specific acoustical impedance(Z), adiabatic compressibility(Кa), Rao’s molarsound function(Rm), Vander Waals constant(b), internal pressure(π), free volume(Vf), intermolecular free path length(Lf), classical absorption coefficient(α/f2)Cl) and viscous relaxation time(τ) were determined using ultrasonic speed(U), viscosity(ƞ) and density(ƿ) data of Schiff bases solutions and correlated with concentration. Increasing linear or nonlinear trends of ( Z, Rm, b, τ and (α/f2)Cl) and decreasing trend of Кa, Lf, π and Vf with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions and solvophilic nature of the Schiff bases, which is further supported by the positive values of solvation number. The nature and position of substituent also affected the strength of molecular interactions.

Thermo-acoustical study of biologically active 1,1’-bis(3-methyl-4-carboxyethylphenoxy) cyclohexane at four different temperatures

Dhaduk B. B., Parsania P. H.

International Letters of Chemistry, Physics and Astronomy

2015

Vol. 47

1--14

Density (ρ), viscosity (η), ultrasonic speed (U), and thermo-acoustical parameters such as specific acoustical impedance (Z), adiabatic compressibility (κa), internal pressure (π), free volume (Vf), inter molecular free path length (Lf), Van der Waals constant (b), viscous relaxation time (τ), classical absorption coefficient (α/f2)cl, Rao’s molar sound function (Rm), solvation number (Sn), Gibbs free energy of activation (ΔG*), enthalpy of activation (ΔH*) and entropy of activation (ΔS*) of biologically active 1,1’-bis(3-methyl-4-carboxyethylphenoxy)cyclohexane (BMCPC) in 1,4-dioxane (DO), ethyl acetate (EA), tetrahydrofuran (THF) have been studied at four different temperatures: 298, 303, 308 and 313 K to understand the molecular interactions in the solutions. A good to excellent correlation between a given parameter and concentration is observed at all temperatures and solvent systems studied. Linear increase or decrease [except (α/f2)cl ] of acoustical parameters with concentration and temperature indicated the existence of strong molecular interactions. ΔG* decreased linearly with increasing concentration and temperature in DO and EA systems and increased with temperature in THF system. ΔH* and ΔS* are found practically concentration independent in case of DO and EA system but both are found concentration dependent in THF system.

Synthesis, Thermal and Crystallographic analysis of 1,1’-diylbis(2-methyl-4-phenylene)bis(2-nitrobenzoate)cyclohexane

Bhavin B. Dhaduk, Chirag B. Patel, Parsania P. H.

International Letters of Chemistry, Physics and Astronomy

2015

Vol. 45

32--41

The crystal structure of 1,1’-diylbis (2-methyl-4-phenylene) bis (2-nitrobenzoate) cyclohexane (NBM-2) has been determined by X-ray crystallographic technique. Single crystals were grown by slow evaporation technique. NBM-2 crystallized in the triclinic crystal lattice having space group P-1. Both the phenyl rings are perpendicular to the cyclohexane ring having chair conformation. NBM-2 showed both inter-and intramolecular interactions. The structure of NBM-2 has also been supported by FT-IR, 1HNMR, 13C NMR, MS techniques. The thermal behaviour of NBM-2 were studied by TGA and DSC techniques at heating rate of 10oC min-1 in nitrogen atmosphere. Thermal stability and kinetic parameters were determined according to Anderson-Freeman method and discussed .