The synthesis of H[Fe,Al]ZSM-5 zeolites with uniform nanocrystals for dimethyl ether to gasoline reaction

The nanocrystalline H[Fe,Al]ZSM-5 zeolites with different crystallization time were synthesized by hydrothermal method, and the evolution process of nanocrystalline H[Fe,Al]ZSM-5 is divided into four stages. The zeolites with uniform nanocrystals could be synthesized at the short time of 4h, and the results of dimethyl ether to gasoline (DTG) reaction indicated that the nanocrystalline H[Fe,Al]ZSM-5 catalysts exhibited the outstanding catalytic performance in DTG process. • Nanocrystal H[Fe,Al]ZSM-5 zeolites with different crystallization time were prepared. • The effect of crystallization time on properties of zeolites was studied in detail. • Nanocrystalline H[Fe,Al]ZSM-5 can be crystalized at short crystallization time of 4 h. • Zeolite with crystallization time of 24 h exhibited the best catalytic performance. The conversion of dimethyl ether to gasoline (DTG) over acidic zeolite catalysts is an important non-petroleum route to obtain transportation fuels due to the current shortage of crude oil resources. Here, the H[Fe,Al]ZSM-5 zeolites with uniform nanocrystals were prepared using hydrothermal method and tested for DTG reaction, and the effects of crystallization time on the physicochemical properties of prepared zeolites were investigated by multiple characterization techniques, such as UV–Vis, 27 Al MAS NMR, XPS, XRD, FT-IR, ICP-AES, SEM, N 2 adsorption–desorption, NH 3 -TPD and Py-IR. The results indicated that the nanocrystalline H[Fe,Al]ZSM-5 zeolites with high crystallinity could be synthesized in the time of as short as 4 h, and Fe species in zeolite framework mainly exist in the form of isolated Fe 3+ in tetrahedral and octahedral coordination. The nanocrystalline H[Fe,Al]ZSM-5 zeolites with crystallization time of 14–48 h had the close and higher acid strength and amounts. The DTG reaction results indicated that the H[Fe,Al]ZSM-5 catalyst with crystallization time of 24 h exhibited the best catalytic performance due to its maximum amount of acid and higher B/L ratio, the DME conversion remained at 100% for about 125 h, and the gasoline yield and the isoparaffin selectivity reached up to 77% and 35.5%, respectively. While the selectivity of aromatics, durene and benzene could be controlled to a low level of about 40%, 2.1% and 0.45%, respectively. The obtained gasoline meets the standard of GB 17930-2011, which could be directly used as the transportation fuel.