Some properties of ammonium exchanged type L zeolite

Abstract

Various properties of ammonium exchanged type L zeolite have been studied. The deammoniation of NH₄–L and the following formation of acidic centres were examined by infrared spectroscopy. Most of the hydroxyl groups and pyridinium ions formed interact with lattice oxygens through hydrogen bonding. The activity of NH₄–L (33) for cumene cracking showed that deammoniation is complete around 350°C and that the dehydroxylation occurs between 500–600°C. The formation of sulphur dioxide anion radicals and perylene cation radicals revealed the charge transfer properties of the zeolite. NH₄–L zeolite with a high degree of exchange is not thermally stable even at 450°C.