Selective disproportionation catalyst and process

摘要

An improved catalytic composite and process are disclosed for the selective disproportionation of toluene. The process uses a layered composite comprising a catalytically active core which comprises a zeolitic aluminosilicate having a SiO2:Al2O3 ratio of 8 to 50 and a relatively inactive protective mantle which preferably comprises boralite. Optionally, the composite is selectively precoked prior to toluene disproportionation. The composite and process provide improved selectivity for the production of paraxylene.