Synthesis and interlayer structure reconstruction of a new layered zeolitic aluminosilicate

A novel layered zeolitic aluminosilicate precursor ECNU-39(P) was hydrothermally synthesized in the fluoride system by using 1-decyl-2,3-dimethylimidazole as an organic structure-directing agent (OSDA) under optimized conditions. ECNU-39(P) was demonstrated to be composed of the MTF layers intercalated by the OSDA cations, possessing a relatively wide interlayer distance. A series of interlayer-expanded zeolites IEZ-ECNU-39 were then readily obtained by post-treating ECNU-39(P) with different silylation reagents in HCl-EtOH solution under suitable temperatures. Various characterizations proved that the silane molecules were inserted into the layer spaces, condensing with the laminate to form interlayer expanded structures. Possessing large interlayer space, the interlayer expansion of ECNU-39(P) was successfully realized by using not only the monomeric silane diethoxydimethylsilane, but also dimeric one 1,1,3,3-tetramethoxy-1,3-dimethylsilane or even four-membered ring silane 2,4,6,8-tetramethylcyclotetrasiloxane. IEZ-ECNU-39 with an enlarged external surface showed a significantly enhanced conversion rate in the acylation reaction of anisole and acetic anhydride.