Sorption of mono-, di-, and trimethylamine on ZK-5 and Y zeolites studied by deuterium NMR

Deuterium NMR is used to study the sorption complexes formed by (methyl-deuterated) mono-, di-, and trimethylamine (MMA-d{sub 3}, DMA-d{sub 6}, and TMA-d{sub 9}) in the acid forms of the zeolites HZK-5 and HY, as well as in dehydroxylated HY and DHY, obtained by high-temperature calcination of HY. The measurements were made in the range {minus}140 to 160{degree}C on samples loaded up to twice the equivalent of the number of Al atoms per unit cell. For HZK-5 the uptake of MMA and DMA is rapid at room temperature, but sorption of TMA requires thermal activation. In HY and DHY all amine gases are readily absorbed upon exposure at room temperature.