Density, viscosity, ultrasonic and thermoacoustic studies of aqueous nicotinamide (Vitamin B3) binary mixtures: Temperature dependence

Abstract

The density ($\rho$) and ultrasonic velocity ($u$) measurements were performed for nicotinamide (Vitamin B₃) in a water medium with various concentrations (0.101 to 1.111) mol·kg⁻¹ in the temperatures range of 298.15 K to 323.15 K. Experimental data is used to estimate volumetric parameters such as apparent molar volume ($V_{\Phi }$), partial molar volume ($V_{\varnothing }^o$), thermoacoustic parameters like adiabatic compressibility ($\beta$), acoustic impedance ($Z$), intermolecular free length ($L_f$), ultrasonic attenuation ($\frac{\alpha }{f^2}$), relative association (RA), relaxation time ($\tau$), and internal pressure (${\pi }_i$). In addition, thermodynamic parameters such as Gibbs free energy ($\Delta G$), Enthalpy ($\Delta H$), and Entropy ($\Delta S$) are also evaluated to interpret the molecular interaction in the medium. The single-point energy calculation is also determined in a gaseous state and an aqueous medium using the IEFPCM model at HF, DFT/B3LYP, and MP2 methods using 6-311G ++(d,p) basis set to estimate the strength of the hydrogen bond. The results are interpreted in terms of structure-making or structure-breaking effects of drug molecules in the mixtures.