Experiments for the Undergraduate Laboratory That Illustrate the Size-Exclusion Properties of Zeolite Molecular Sieves

• Autores: Jason Cooke, Eric J. Henderson
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 86, Nº. 5 (May), 2009, págs. 606-609
• Idioma: inglés
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• Resumen

  • Experiments are presented that demonstrate the size-exclusion properties of zeolites and reveal the reason for naming zeolites "molecular sieves". If an IR spectrometer is available, the adsorption or exclusion of alcohols of varying sizes from dichloromethane or chloroform solutions can be readily demonstrated by monitoring changes in the intensity of the alcohol OH band in the IR spectra. It is also possible to qualitatively illustrate whether solvents of varying sizes are able to enter the pores of different zeolites by observing the displacement of adsorbed nitrogen gas from within the pores. The volume of evolved gas is considerable and can be measured if desired.