| abstract |
In a process for modifying the shape selectivity of an aluminosilicate zeolite catalyst having a silica to alumina molar ratio less than 500, the catalyst is exposed to at least two ex situ selectivation sequences, wherein each ex situ selectivation sequence includes the steps of contacting the catalyst with a selectivating agent, normally an organosilicon compound, in a carrier and subsequently calcining the catalyst. |