Aromatization

Catalysis

Engineering

Petrochemical

Biochemistry

Methanol

Chemical engineering

Toluene

Hydrogen

Organic chemistry

Oxygen

Zeolite

Partial pressure

Chemistry

Selectivity

Dehydration

Benzene

Coke

ACS Catalysis

In the current petrochemical market, the global demand for aromatics, especially benzene, toluene, and xylenes (BTXs), has increased sharply. The methanol-to-aromatic conversion (MTA) over ZSM-5 is among the most promising routes to satisfy this ever-growing demand. In this work, we show that high-pressure operation during MTA leads to a large increase in aromatic selectivity while enhancing stability on-stream. Stable operation along with a very high selectivity to aromatics (up to 50%, with 20% BTXs) can be achieved on a commercial high-silica ZSM-5 (SiO2/Al2O3 = 280) at 400 °C, 30 bar total pressure, and WHSV = 8 h–1. The high partial pressure of primary olefins and the promoted methanol-induced hydrogen-transfer pathway result in an exponential increase in aromatization, while the high partial pressure of steam generated via dehydration of methanol leads to in situ coke removal and, therefore, to a much slower deactivation of the zeolite.

Highly Selective and Stable Production of Aromatics via High-Pressure Methanol Conversion