Zeolite transitional form of selective restriction

Some reaction, reactant molecules and their molecular products are not subject to restrictions window catalyst pore diffusion of knowledge within the required holes or due to a larger cage cavity space to form the corresponding transition states, or is restricted so that the reaction can not be ; on the contrary, some of the reactions yo ah just a small space of the transition state would not accept that kind of restriction, which constitutes a selective type catalytic transition state restrictions.
ZSM-5 zeolite used in this transition state selectivity of catalytic reactions, the biggest advantage is to prevent coking. Because ZSM-5 zeolite 5a having a smaller than the other bore, is not conducive to Jiaosheng Cheng precursor polymerization reaction requires a large transition state formed. Thus has a longer life than other molecular sieves and amorphous catalyst.