Effect of alkaline earth on crystal sizes of ZSM-5 type zeolites and theircatalytic properties for alkylation of toluene with methanol

Various ZSM-5 type zeolites containing alkaline earth metals with SiO2/Al2O 3 ratio 160 were synthesized by varing the OH . /SiO2 ratio in the synthesi s mixture. The crystal shape, acidity, steaming durabilities and catalytic properties for the alkylation of toluene with methanol were investigated. Pyridine TPD showed that the total amount of acid sites is equal to the amo unt of Al in H-ZSM-5 structure regardless of containing alkaline earth meta ls. H-ZSM-5 containing alkaline earth metals had the same amount of total a cid sites, however it had larger crystal size and larger amount of weak aci d sites than H-ZSM-5 without alkaline earth metals. H-ZSM-5 containing alka line earth metals had larger total amount of acid sites, especially weak ac id sites after steaming treatment at 973 K than H-ZSM-5 without alkaline ea rth metals. H-ZSM-5 containing alkaline earth metals had better catalytic alkylation ac tivities of toluene with methanol. H-ZSM-5 containing Mg especially showed superior p-xylene selectivity to equilibrium p-xylene selectivity in xylene products.