Studies on synthesis, volume and conductivity behaviors of three novel pharmaceutical salts [CnPy][AceSA] (n = 8, 10, 12)

Abstract

In the present work, three new pharmaceutical salts based on N-alkyl-pyridinium ([CnPy]+, n = 8, 10, 12) as the cations and acetyl-sulfacetamide ([AceSA]-) as an anion were synthesized. The thermal stability was measured by synchronous thermal analyzer. The solvation and micellization behaviors in aqueous solution were investigated by experimental density and conductivity data at different temperatures. These data were used to calculate the apparent molar volume at infinite dilution, V2,φ0, the apparent molar expansibility at infinite dilution, Eφ0, limiting molar conductivity, Ʌ0, critical micelle concentration, cmc, and the relative thermodynamic functions for the micellization of [CnPy][AceSA] in aqueous solution. The effect of the aliphatic chain length of N-alkyl-pyridinium cation and temperature on the estimated properties was examined. The obtained results confirmed that [CnPy]+(n = 8, 10, 12) cations with longer alkyl chain exhibit higher decomposition temperature, large V2,φ0, low cmc and Ʌ0 values. The results were discussed in terms of solute–solvent interactions and structural changes of [CnPy][AceSA] in water.