Promoted catalytic behavior over γ-Al2O3 composited with ZSM-5 for crude methanol conversion to dimethyl ether

γ-Al 2 O 3 was composited with ZSM-5 molecular sieve to improve its catalytic performance and hydrothermal stability during the conversion of crude methanol into dimethyl ether (DME). When prepared by a liquid-phase coating chemical compounding, the ZSM-5/γ-Al 2 O 3 composite catalyst reached an excellent methanol conversion of 91.9% and DME selectivity of 100%. The DME yield was increased by about 13% compared to only using γ-Al 2 O 3 . Partial desiliconization and dealumination of the ZSM-5 molecular sieve effectively reduced the surface acid center strength and increased the mesoporous ratio. The special composite phase interface effectively decreased surface charge density of γ-Al 2 O 3 and formed the B (Brønsted) - L (Lewis) synergistic active centers. All these factors contribute to improving the catalytic performance, hydrothermal stability and resistance to deactivation of ZSM-5/γ-Al 2 O 3 during the conversion of crude methanol to DME.