The effect of zeolite structure ont he disproportionation of trimethylbenzenes to xylenes and tetramethylbenzenes

摘要

The effect of dimensionality and channel geometry of different structural types of zeolites on the conversion and selectivity in the disproportionation of 1,3,5- and 1,2,4- trimethylbenzenes was investigated. Large pore zeolites of MOR, FAU and BEA structures exhibit high activity in this disproportionation, however, FAU is not stable in long time-on-stream experiments due to a severe deactivation. In addition, significant dealkyation of trimethylbenzenes was found for MOR and FAU. The results indicate that the reaction rate is strongly influenced by the transport of bulky trimethylbenzenes. BEA with high conversion and selctivity to xylenes and tetramethylbenzenes was shown to be a stable catalyst in time with high resistance to deactivation particularly at shorter contact times.