Petaloid ZnAlOx/HZSM-5 catalyst with metal modification for highly selective conversion of syngas to value-added aromatics

Syngas can be efficiently converted to multimethylbenzenes by integrating a methanol synthesis catalyst with HZSM-5 zeolites, where 1,2,4,5-tetramethylbenzene (durene) is a high value-added product used in polyimide synthesis. Here, we synthesized a Mn modified ZnAlOx catalyst with petaloid structure and integrated with HZSM-5 as a bifunctional catalyst for targeting the high selectivity durene. Various characterization approaches including XRD, BET, XPS, SEM, TEM, TPD, TPR, and in-situ FTIR were adopted to illustrate the deeper analysis of highly efficient catalyst. It was demonstrated that the strong synergy of ZnAlOx staggered sheet and nanoclusters MnOx caused higher concentration of H3CO* species and methanol/DME intermediates, which promote the methylation of trimethylbenzene over HZSM-5 zeolites. The combination 7%Mn-ZnAlOx/ HZSM-5 exhibited a high CO conversion of 56.4% and 44.6% tetramethylbenzene selectivity at 360 ℃ and 5.0 MPa, with an excellent stability of 100 h. In addition, through trace methanol co-feeding experiment, it was proposed that there is an appropriate amount of methyl intermediates to match with the synthesized zeolite to obtain a maximum selectivity to tetramethylbenzene.