Synthesis of durene from methanol over alkali and acid modified HZSM-5

Alkali and acid modified HZSM-5 molecular sieves were prepared through treating with different alkali solutions together with nitric acid of different concentrations; four catalysts, i.e. H(0.2)-Na-ZSM-5, H(0.5)-Na-ZSM-5, H(0.2)-K-ZSM-5 and H(0.5)-K-ZSM-5 were obtained. These catalysts were characterized by means of XRD, NH₃-TPD, ICP, FT-IR and Py-IR; their performance in the synthesis of durene from methanol was investigated in a fixed-bed down-flow reactor. The results showed that the highest selectivity to durene for methanol aromatization is achieved over the H(0.2)-K-ZSM-5 catalyst, which should be ascribed to its large pore size and abundant weak B acid sites arising from the alkali and acid modification.