343
13-P-14 - D y n a m i c behaviour of acetonitrile molecules adsorbed in ALPO45 and S A P O - 5 studied by solid N M R method S. Ishimaru, M. Ichikawa, K. Gotoh and R. Ikeda
Department of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan We studied characteristics of micropores in molecular sieves A1PO4-5 and SAPO-5 by observing IH and 2H NMR to detect dynamic behaviour of acetonitrile molecules adsorbed in the pores. From 2H spectra and ~H relaxation times, it was shown that the molecular motion was strongly affected by the existence o f - O H groups on the pore-wall of SAPO-5. The details of the motions are discussed from ~H NMR TI and T2 data.
13-P-15 - D e t e r m i n a t i o n of the Si/A! ratio of faujasite-type zeolites C.H. Rtischer l*, J.-C. Buhl I and W. Lutz 2
llnstitut fiir Mineralogie, Universit~itHannover, Welfengarten 1 Hannover, Germany. *C.Ruescher@mineralogie. uni-hannover,de 2WITEGA Angewandte Werkstoff-Forschungg. GmbHBerlin, Germany Zeolites Y dealuminated by Si/A1 substitution using SIC14 (DAY-S) and dealuminated thermochemically in steam (DAY-T) were investigated by X-ray powder diffraction, infrared spectroscopy and wet chemical methods. The dependence of lattice constants (a) on the molar ratio x = (I+Si/A1) z show non-ideal solid solution behaviour. In a first approximation the change in a (in nm) can be described as: a = 0.187x+2.412, for 0.1 < x < 0.5. For x < 0.1 the change in lattice constant saturates towards a = 2.425 nm. A similar shift in the double ring mode (WDR)is observed, tailing off.
13-P-16 - Theoretical investigation toluene adsorbed on zeolite X
of the chemical shift anisotropy
of
A. Simperler (a), A. Philippou (b), D.-P. Luigi (b), R.G. Bell (a) and M.W. Anderson (b)
a The Royal Institution of Great Britain, London, United Kingdom,
[email protected] b UMIST Centre for Microporous Materials, Manchester, United Kingdom Adsorption of toluene on zeolites Li-X, Na-X, K-X, Rb-X, and Cs-X has been investigated with quantum chemical methods. Calculations of geometries, Mulliken partial charges, and 13C chemical shift parameters of clusters representing the catalytically active site are presented. The polarisation of the toluene carbons is the first step in alkylation reactions catalysed by zeolites and, at an early stage, will influence the outcome of the reaction. We show the simultaneous influence of the Lewis acidic cation and the basicity of the zeolite is responsible for altering the electron distribution within the toluene and thus affecting the outcome of an alkylation reaction.