Investigations of the structure orienting role of acyclic molecules containing (—OCH2CH2—) groups in the synthesis of high-silica faujasitelike zeolites

The possible structure-directing role of acyclic (—OCH2CH2—)-containing molecules in the synthesis of faujasitelike zeolites was investigated. FAU silica-rich frameworks were obtained by using tris(3,6-dioxaheptyl)amine (TDA-1) and poly(ethylene oxides) (PEO) with a molecular weight ranging from 2000 to 8000. The solids were characterized by chemical analysis, thermal analysis, and MAS n.m.r. spectroscopy. The Si/Al molar ratios (3.4–3.6) are higher than those of conventional Y zeolite (2.7) but slightly lower than the Si/Al ratio of a FAU zeolite prepared in the presence of 15-crown-5 (3.8). The acid properties of the materials synthesized with PEO 3400, TDA-1, and 15-crown-5 were studied comparatively by NH3 STD.