Ketones in Silicalite

Inclusion of the different ketones in Silicalite was achieved as described previously (14,15), using 2,2,4-trimethylpentane (isooctane) as a solvent for the ketones. In our study of substituent effects we have used 120 mg of ketone per gram of Silicalite in all inclusion attempts. The quantities used would yield samples in which up to 60% of the void volume of Silicalite (0.19 mL/g) could be occupied. The actual yields (and therefore the efficiency of inclusion) were determined by microanalysis, and the results are listed in Table I. 

Site Inhomogeneity. In all cases where we observed phosphorescence emission from ketones in Silicalite the decay of this luminescence was non-exponential. In this respect, it should be noted that lifetimes given in Table I and in earlier papers in this series refer to the first observable lifetime following a 10 ys excitation pulse and a 20 ys delay. All values are comparable and probably reflect a similar degree of immobilization. Non-exponential decays... 

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