An NMR Study on the Dynamic Behavior of Triethylamine Included in AFI Crystals - Influence of Acid Sites on the Motional State of Triethylamine Molecules -

The 1H NMR spin-lattice relaxation times (T1) of triethylamine (TEA) molecules included in five kinds of AFI crystals with different concentrations of Si atoms in the wall were measured. The temperature and Larmor frequency dependences of T1 were well explained by introducing a distributed motional correlation time ((tau)) for the pseudo-C3 TEA reorientation. An obtained linear decrease in the (tau) distribution width with an increase of the Si concentration, i.e., the number of Bronsted acid sites, was shown to be related to the orientations of TEA molecules in channels.