Abstract
The interactions between tetrapropylammonium cations and the silica nanoparticles present in silicalite-1 precursor solutions were characterized at 70 °C using in situ pulsed field gradient (PFG) NMR experiments. In situ PFG NMR results show that the organocation diffusion coefficients at 70 °C are larger than those at 25 °C. Although the adsorption isotherms calculated from the diffusion data present similar trends at both temperatures, the adsorption isotherms at 70 °C could not be accurately described using a Lineweaver–Burk analysis. Therefore, the Freundlich equation was used to fit the adsorption data and Gibbs free energies between 6 and 15 kJ/mol were obtained. Time evolution studies show that organocation diffusion coefficients increased with the time, reached a maximum at about 6 days, and trended to a plateau towards the end of the synthesis. This maximum in the diffusion coefficient of the organocation coincides in time with the exothermic–endothermic transition that is known to occur near the...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
