| Popis: |
The catalytic pore size of ZSM-5 has been determined on the basis of the sizes of molecules converted during the dewaxing of waxy distillate chargestocks. From conversions of alkane and alkylbenzene molecular classes, ZSM-5 behaves in catalytic conversions as if it has an elliptical pore with the approximate dimensions of 0.55 × 0.7 nm and can in fact discriminate by both molecular size and shape. Other zeolites have been similarly examined: the catalytic pore sizes of mordenite and ZSM-23 are 0.9-1.0 nm and 0.45 × 0.65 nm, respectively. The catalytic pore sizes are always larger than computed crystallographic pore sizes, a phenomenon generally observed in adsorption measurements. |
