TEMPERATURE-PROGRAMMED DESORPTION OF METHYLNAPHTHALENE FROM ALKALI-METAL FAUJASITES

Interaction between 1-methylnaphthalene and alkali-metal X and Y zeoli tes has been investigated using TPD. All spectra show only a single pe ak, the temperature of which changes with the nature and amount of the alkali-metal cation and the Si/Al ratio of the faujasite. A correlati on between peak temperature and average charge of structural oxygen at oms of the zeolite is shown. On the basis of the atomic charge distrib ution in the 1-methylnaphthalene molecule. it is suggested that adsorp tion is initiated by interaction between the alkali-metal cation and t he carbon atom of the methyl group. Simultaneously, an interaction inv olving hydrogens atoms of the aromatic rings and structural oxygen ato ms of the zeolite occurs, except for X samples containing high amounts of large alkali-metal cations.