Solid acids as catalysts for cumene cracking: heteropolyacids as compared with zeolites. Part. 1. Reaction and coke formation

The catalytic properties of dodecatungstosilicic acid H(4)SiW(12)O(40 (HPA) and NaHY-88 zeolite in cumene cracking reaction were compared. HPA exhibits catalytic activity at temperatures lower (below 160° C) than NaHY-88 (above 170°C) but its deacti-vation is faster. Mass balance shows that in both cases a certain deficit exists due to the formation of carbonaceous deposits. It has been shown that in the formation of deposits both chain hydrocarbons ("propylene deposit") and aromatic ones ("cumene deposit") participate. In the case of both catalysts the course of catalytic reaction and deposit formation were influenced by the contact time. The results enabled us also to propose some conclusions concerning the geometry of deposit distribution in both catalysts.