Co-conversion of methanol and n-hexane into aromatics using intergrown ZSM-5/ZSM-11 as a catalyst

The conversion of n-hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization.In this study,intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-1I zeolites.The physicochemical properties of ZSM-5/ZSM-l1 intergrown zeolite were analyzed using X-ray diffrac-tion,N2 isothermal adsorption-desorption,the tempera-ture-programmed desorption of ammonium,scanning clectron microscopy,Fourier transform infrared spectra of adsorbed pyridine,and nuclear magnetic resonance of 27AI,and compared with those of the ZSM-5 and ZSM-11 zeolites.The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and n-hexane under the fixed bed conditions of 400℃,0.5 MPa(N2),methanol:n-hexane=7:3(mass ratio),and weight hourly space velocity=1 h 1(methanol).Com-pared to the ZSM-5 and ZSM-11 zeolites,the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area,a unique crystal structure,moderate acidity,and suitable Brensted/Lewis acid ratio.The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate,n-hexane conversion rate,and aromatic selectivity.The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal.structure.The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.