Volumetric and ultrasonic investigation of molecular interactions of l-serine and l-threonine in aqueous nicotinamide solutions at TÂ =Â (288.15-318.15) K

In this work, densities and speeds of sound have been measured for l-serine and l-threonine in aqueous solutions of nicotinamide at T = (288.15, 298.15, 308.15, 318.15) K and atmospheric pressure. The apparent molar volume (Vϕ), the limiting apparent molar volume (Vϕο) and limiting apparent molar volumes of transfer (ΔVϕο) for amino acids from water to aqueous nicotinamide have been calculated from density data. The limiting apparent molar expansibilities have also been calculated. Apparent molar isentropic compression (Kϕ , s), limiting apparent molar isentropic compression (Kϕ , sο) and limiting apparent molar isentropic compression of transfer (ΔKϕ , sο) have been calculated from speed of sound data. The pair and triplet interaction coefficients are obtained from limiting apparent molar volumes of transfer and limiting apparent molar isentropic compression of transfer. The present study deals with the structure-making and breaking behavior of l-serine and l-threonine in aqueous nicotinamide solutions.