What is shape selective catalysis?
Answer:
The catalytic reaction that depends upon the pore structure of the catalysis and the size of the reactant and product moecule is called shape selective catalysis.
A shape selective catalyst has a variety of active sites of different shape and size. Zeolite acts as a shape selective catalyst. In the crystal of a zeolite the pore size usually varies form 260 pm to 740 pm. If the reactant molecules are too large they can not fit into pores of zeolite and no reaction takes place. On the other hand. If the reactant molecules ZSM-5 is used as shape selective catalyst to produce gasoline of high octane number from methanol.
where, x varies form 5 to 10. ZSM-5 stands for zeolite sieve of molecular porosity-5.
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