Synthesis of four monodimentional medium-pore molecular sieves and their hydroisomerization performances of n-dodecane

摘要

SAPO-11, SAPO-41, ZSM-22, ZSM-12 were synthesized by the hydrothermal method and characterized by XRD, SEM and NH_3-TPD. Effects of pore channel, the number of acid sites and acid strength on hydroisomerization of n-dodecane were examined over Pt-loaded corresponding zeolites. The results indicate that the selectivity to isomers in hydroisomerization of n-dodecane is highly influenced by channel structure in zeolites and the conversion activity of n-dodecane is dependent on acidity of zeolites. Monodimensional ten-ring molecular sieves are ideal catalytic materials for higher isomerization selectivity in hydroisomerization of n-dodecane regardless of acid strength, such as SAPO-11, SAPO-41 and ZSM-22.