Study of Thermodynamic Parameters and Viscosity Behavior of Substituted Pyrazolines in 70% Dioxane-Water-Part—II*

Abstract

Viscosity measurements have been made on system comprising
1-carboxamido-3-(2'-hydroxy-3'-bromo-5'-chlorophenyl)-5-phenyl
Δ²-pyrazoline (ligand 1) and 1-carboxamido-3-(2'-hydroxy-3'-nitro-
5'-chlorophenyl)-5-phenyl-Δ²-pyrazoline (ligand 2) in 70% dioxanewater
mixture solvent at different temperatures. The data have been
used to calculate viscosity and thermodynamic parameters, such as
ΔG*,  ΔH* and  ΔS*. We have also studied the effect of solvent on
the viscosity at 30°C. It has been found that viscosity increases with
increase in the percentage of dioxane. Also viscosity increases due
to increase in the concentration of ligand 1 and ligand 2 in 70%
dioxane-water mixture. In the presnt investigation  β-coefficient
value of ligand 2 is greater than the value of ligand 1 in dioxane-water
mixture. We have also calculated the thermodynamic
parameters  ΔG*,  ΔH* and  ΔS* for ligand 1 and ligand 2 which
showed that the process is spontaneous and irreversible.