Enhancing BTX selectivity of the syngas to aromatics reaction through silylation of CTAB pretreated ZSM-5

Abstract

Silylation of CTAB pretreated ZSM-5 combined with ceria–zirconia solid solution (CZS) was performed and this was used as a bifunctional catalyst for syngas conversion into light aromatics. The pretreatment with CTAB can significantly increase the external acidity of the zeolite, which can facilitate the formation of a dense SiO₂ layer in the subsequent silylation process. After the silylation, the external acidity was significantly reduced, which was proved by Py/DTBPy-IR and 1,3,5-TIPB cracking results. Meanwhile, the diffusion of trimethylbenzene was also inhibited, thus minimizing the side reactions. As a result, 82.2% fraction of light aromatics with a selectivity to total aromatics of 72.8% can be achieved with a CO conversion of 34.7% over the CZS/PZ5-Si3 bifunctional catalyst.