Intracrystalline diffusivity of hydroxybenzenes in TS-1 and Al-free Ti-beta

Autor: E. van Steen, K.P. Möller, U. Wilkenhöner, W.L Duncan
Rok vydání: 2004
Předmět:
Zdroj: Microporous and Mesoporous Materials. 69:181-186
ISSN: 1387-1811
DOI: 10.1016/j.micromeso.2004.01.007
Popis: The diffusivity of phenol, catechol and hydroquinone was determined using zero length column chromatography (ZLC) with water and methanol as a solvent. With methanol as a solvent the diffusivity of phenol in TS-1 is larger than that of catechol and hydroquinone, which are approximately identical. When using water, the diffusivity of phenol in TS-1 is lower than that of catechol, which is lower than that of hydroquinone. The diffusivity of the various compounds can be correlated with the strength of adsorption, i.e. the higher the strength of adsorption the lower the diffusivity. The anomaly observed in the order of diffusivity of the hydroxybenzenes in TS-1 in water is ascribed to the polarisation of the aromatic ring in conjunction with the strong preferential adsorption of the hydroxybenzenes. The diffusivity was also determined as a function of the pore geometry. The phenol diffusivity in water is in zeolite TS-1 ca. 8 times lower than the diffusivity in zeolite Ti-beta.
Databáze: OpenAIRE
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