CHARACTERIZATION OF SMALL-PORE AND INTERMEDIATE-PORE ZEOLITES BY MEANS OF TEMPERATURE-PROGRAMMED DESORPTION OF AMINES

This paper presents results of temperature-programmed desorption (TPD) as a method for studying the acid and shape-selective properties of s mall- and intermediate-pore zeolites. A combination of an in situ infr ared spectrometer and a downstream gas chromatograph for analyzing the desorption products is used to detect the desorption process. This is followed by a separate, newly installed microbalance facility. The st udies show that a part of the amines, esp. dimethylamine (DMA) and tri methylamine (TMA), adsorbed on the zeolites undergo decomposition, dis proportionation and carbonization reactions during the TPD measurement at elevated temperatures. Comparison of the microbalance measurements and the gas chromatographic results give a good picture of the extent of these reactions.