Steam and acid dealumination of mordenite Characterization and influence on the catalytic performance in linear alkylbenzene synthesis

摘要

A systematic study of both acid and steam dealumination of mordenite has been carried out aiming to obtain a mordenite featuring high acid strength active sites along with a secondary mesoporous system,in order to maximize both catalytic performance and time-on-stream stability of the material in solid-acid catalyzed alkylation of benzene with 1-dodecene.Detailed assessment of the textural (XRD,N_2 adsorption-desorption) and acid (FTIR of pyridine adsorption) properties of the obtained materials was performed.It has been found that catalysts obtained by combined steam dealumination and acid washing show a dramatic increase in the intrinsic activity and a significantly lower tendency to suffer deactivation when compared to the parent zeolite and samples obtained by acid treatments.This improved behaviour of the steam-treated sample is attributed to its increased mesoporous surface area,lower acid sites concentration and less hydrophilic surface.