Synthesis, characterization, and catalytic properties of interlayer expanded aluminosilicate IEZ-PLS-3

An interlayer expanded zeolite IEZ-PLS-3 was postsynthesized from the lamellar precursor of PLS-3 aluminosilicate by interlayer silylation with diethoxydimethylsilane (DEDMS) in HCl-EtOH solution at 443 K for 20 h. The resulting material was characterized by various techniques such as XRD, SEM, adsorption of N₂, water, and benzene, and IR and NMR spectroscopies, and its catalytic properties were investigated by comparison to those of other zeolites with similar Si/Al ratios in m-xylene isomerization/disproportionation, Friedel-Crafts alkylation of anisole with benzyl alcohol, and acylation of anisole with acetic anhydride. The interlayer expansion created new 12 × 10-membered ring (MR) pores in IEZ-PLS-3. IEZ-PLS-3 showed a larger adsorption capacity of benzene than conventional PLS-3 with 10 × 8-MR channels. In the m-xylene isomerization/disproportionation reaction, IEZ-PLS-3 showed a higher conversion than PLS-3 and gave an isomerization to disproportionation ratio close to that of Beta zeolite, characteristic of shape-selective properties of 12-MR zeolites. IEZ-PLS-3 was more active than Beta in Friedel-Crafts alkylation and acylation reactions, implying that it is a promising solid acid catalyst for processing bulky molecules.