The effects of sodium chloride on the diffusion of sulfonated resorcinarenes in aqueous solutions

• Published in: Fluid phase equilibria Vol. 518; p. 112629
• Main Authors: Galindres, Diana M., Ribeiro, Ana C.F., Esteso, Miguel A., Vargas, Edgar F., Leaist, Derek G., Rodrigo, M. Melia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2020
• Subjects: Diffusion coefficient; Sulfonated resorcinarenes; Taylor dispersion; Tracer diffusion; Transport properties; Tracer diffusion; Sulfonated resorcinarenes; Taylor dispersion; Transport properties; Diffusion coefficient
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2020.112629

The effect of sodium chloride on the diffusion of aqueous Na4ETRA (tetrasodium 5,11,17,23-tetrakissulfonatemethylen-2,8,14,20-tetra(ethyl)resorcin[4]arene) and Na4PRRA (tetrasodium 5,11,17,23-tetrakissulfonatemethylen-2,8,14,20-tetra(propyl)resorcin[4]arene) are investigated by using the Taylor dispersion technique to measure diffusion in aqueous resorcinarene solutions with and without added NaCl. In binary solutions of Na4ETRA or Na4PRRA (no added NaCl), the ETRA4− and PRRA4− ions diffuse at the same speed as the Na+ counterions to maintain electroneutrality. As a result, the binary diffusion coefficients of the resorcinarenes are weighted averages of the diffusion coefficients of the ETRA4− or PRRA4− ions and the relatively mobile Na+ ions. As the NaCl concentration is raised, the diffusion coefficients of Na4ETRA and Na4PRRA drop to the tracer diffusion coefficients of ETRA4− or PRRA4− ions in a supporting NaCl electrolyte solution. Coupled diffusion of Na4ETRA and Na4PRRA with NaCl is significant, driven primarily by the electric field (diffusion potential) generated by concentration gradients in Na4ETRA, Na4PRRA and NaCl. Tracer diffusion coefficients for Na4ETRA and Na4PRRA in aqueous systems containing NaCl. [Display omitted] •Tracer diffusion coefficients for Na4ETRA and Na4PRRA in water.•Tracer diffusion coefficients for Na4ETRA and Na4PRRA in aqueous systems containing sodium chloride.•Coupled diffusion by using Nernst equations.