ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A volumetric study of ionic interactions of ammonium sulfate in water and aqueous DMF at different temperatures

Syed Muhammad Saqib Nadeem

Public Sector Organization, Karachi, Pakistan

E-mail: smsaqibnadeem@gmail.com

Received: 2 October 2021  Accepted: 5 March 2022

Abstract:

Densities of ammonium sulfate solutions in water and aqueous dimethylformamide were measured at temperatures of 303.15, 308.15, 313.15, 318.15, and 323.15 K. The range of ammonium sulfate concentration was from 1.02 × 10^–2 to 9.19 × 10^–2 mol kg⁻¹. The density data were used for the calculation of apparent molar volumes (V_ϕ). A Masson’s equation was fitted to the apparent molar volumes for the evaluation of limiting apparent molar volumes. The structure-making or structure-breaking ability of ammonium sulfate was determined by studying the variation of limiting apparent molar volume (V_ϕ^o) with temperature by calculating the Hepler’s constant (δ²V_ϕ^o/δT²)_P. The value of Hepler’s constant confirmed the structure-breaking behavior of ammonium sulfate in water and aqueous DMF in the specified temperature range. The limiting apparent molar volume of transfer (Δ_tV_ϕ^o) and limiting apparent molar expansibilities (E_ϕ^o) were calculated to explain solute–solvent interactions in terms of solvation behavior of ammonium sulfate concerning temperature. Isobaric thermal expansion coefficients (α_p) were calculated to provide supporting evidence. The results are interpreted in terms of structural and electrostatic interactions.

Graphical abstract

Keywords: Limiting apparent molar volume; Dimethylformamide; Ammonium sulfate; Hepler’s constant; Solute–solvent interactions

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02172-6

Chemical Papers 76 (7) 4419–4429 (2022)