This study aims to compare the catalytic performance of ZSM-5 and SAPO-34 zeolite catalysts in the conversion of ethanol. Through experiments conducted at different temperatures (773 and 673 K)

it was found that SAPO-34 initially exhibits superior propylene selectivity compared to ZSM-5. However

the propylene yield on SAPO-34 gradually decreases

while the ethylene yield increases with time on stream. Density functional theory calculations were employed for the investigation of the reaction mechanism. The results indicate that the SAPO-34 catalyst surface favors propylene desorption

which is beneficial for its initial high propylene selectivity. Nevertheless

the smaller pore structure of SAPO-34 limits the effective diffusion of products

leading to product accumulation within the pores and potentially causing catalyst coking and deactivation. By combining the experimental results with theoretical calculations

this study not only explored the selectivity difference between SAPO-34 and H-ZSM-5 in ethanol conversion reaction but also revealed the influence of different molecular sieve catalyst structures on product distribution and catalyst stability.