Zeolite synthesis using 1,4-diazabicyclo[2,2,2]octane (DABCO) derivatives as structure-directing agents

A number of 1,4-diazabicyclo[2,2,2]octane (DABCO) derivatives are used as s tructure-directing agents in high-silica, zeolite syntheses in the presence and absence of Al3+, B3+ and Zn2+. Several high-silica products including phases with unknown structure are synthesized. The results suggest that the product selectivity can be influenced by methyl-substitution of the DABCO moiety. However, when using DABCO-polymers, the number of methylene carbon atoms between the DABCO units rather than methyl-substitution of DABCO has the largest effect on the final products formed. C-13-CP MAS NMR results sh ow that the signal attributed to the carbon atoms in the DABCO unit in both a DABCO polymer and 1,4-diazoniabicyclo [2,2,2]octane,1,4-dimethyl are spl it into two signals when these organics are guests in zeolites. The data su ggest that the ionic interactions between two cation sites of the DABCO uni t and the zeolite framework are different. (C) 1999 Elsevier Science B.V. A ll rights reserved.