2 Materials and methods
2.1 Chemicals
Aluminum sulfate octadecahydrate
(Al2(SO4)3.18H2O),
silica sol (40 wt% aqueous solution) and sodium chloride (NaCl) were
purchased from Aladdin Co., Ltd. Tetrapropylammonium hydroxide (TPAOH,
25 wt% aqueous solution) was purchased from Innochem Co., Ltd.
C4-olefin was provided from Shanghai Petrochemical Company.
2.2 Catalyst preparation
Four operating processes for the synthesis of ZSM-5 zeolites, including
RPB premix - static crystallization, RPB premix - dynamic
crystallization, STR premix - static crystallization, and STR premix -
dynamic crystallization, are schematically showed in Fig. 1.