Preparation of porous materials with nitrogen in the framework

Authors:

• Stanisław Kowalak,
• K. Held,
• R. Kociński,
• Ł. Szymański,
• Ewa Agnieszka Janiszewska

Abstract

The binary porous materials containing nitrogen (imido-, nitrido- groups) as a bridging anions between the framework atoms such as Si, Al, P, Sn, Zn, B have been prepared mostly by joint ammonolysis of chlorides of respective elements. The products comprising two different framework elements (e.g. Si/Al, Al/P) were also obtained by separate ammonolysis of substrates followed by mixing of resulting amides or imides. The products were always amorphous, but after thermal removal of NH₄Cl they showed high surface area and some ordering of mesoporous system. The attempts to crystallize them in liquid ammonia or other aprotic solvents with contribution of alkalis (e.g. NaNH ₂) usually did not result in products of distinct crystallinity, moreover their porosity was always drastically decreased. Some of the samples (particularly binary Si/Al, Al/P systems) showed a noticeable catalytic activity in propan-2-ol decomposition, which reflected the presence of acid sites. © 2005 Elsevier B.V. All rights reserved.