日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

The catalytic performance of various solid acids was investigated for cracking of paraffin into light olefins (ethylene and propylene) using n-butane as a substrate. The MFI type zeolites showed the highest yield of olefins among the catalysts studied. The modification of the MFI zeolites with the transition metals such as Fe, Co, Zn stimulated the dehydrocyclization of paraffin into aromatics and the yield of olefins was lowered. It was found that the high selectivity of olefins was achieved using the alkaline earth-modified and the rare earth-modified MFI zeolites. The NH₃-TPD analyses proved that the acid characters of the zeolite were changed with the alkaline earth-modification, while those with the rare earth-modification were almost unaffected. It was suggested that the other factors than acid such as changes in adsorption characters on zeolite affected the olefin selectivities.