Industrial & Engineering Chemistry Research, Vol.58, No.42, 19446-19455, 2019
Methanol Aromatization over Mg-P-Modified [Zn,Al]ZSM-5 Zeolites for Efficient Coproduction of para-Xylene and Light Olefins
In this work, a series of [Zn,Al]ZSM-5 zeolites was synthesized via isomorphous substitution using different Zn precursors, and the as-obtained zeolites were further subjected to Mg-P surface modification for efficient production of p-xylene and light olefins (C-2(=) approximate to C-4(=)) from methanol. The synthesized [Zn,Al]ZSM-5 zeolites are highly active in methanol to aromatics (MTA) reaction. Ascribed to the uniformly dispersed Zn species and greatly enhanced dehydro-cyclization reaction, [ZnS]ZSM-5 synthesized from ZnSO4 exhibited the most efficient MTA performance (similar to 62 wt % aromatics yield). Through fine modulation of zeolite pore openings and acidic properties, the subsequent Mg-P comodification improved the shape selectivity to p-xylene and also led to abundant coproduction of light olefins. The resultant Mg-P/[ZnS]ZSM-5 catalyst showed an outstanding performance for methanol aromatization in both this work and the open literature, directly yielding similar to 23 wt % p-xylene (similar to 187% para-selectivity) from methanol feedstock.