US Patent 7446071 Catalytic naphtha cracking catalyst and process

A process is disclosed for enhancing the production of light olefins using a catalyst with small pores. The catalyst comprises a layered zeolite material comprising an inner layer having pores of 8 or 10 membered rings and an outer layer having pores of 10 membered rings. The pores in the outer layer overlaying the pores in the inner layer. The zeolite has a silicon to aluminum atomic ratio of about 20 to about 200 and its surface acid sites external to the pores have been substantially neutralized.