chapter  2
16 Pages

Amine-Assisted Synthesis of Aluminum Oxide

WithAlexander I. Kozlov, Mayfair C. Kung, Wen-Mei Xue, Harold H. Kung, Shandong Yuan

Abstract .................................................................................................................... 15 2.1 Introduction .................................................................................................... 15 2.2 Preparation and Properties of Amine-Al Alkoxide Complexes.................... 17 2.3 Hydrolysis of Al(OBut)3(C8H17NH2) and

Al(OBut)3(Pipy) to Form Al2O3-Amine......................................................... 22 2.4 Characterization of Al2O3-Amine .................................................................. 23

2.4.1 NMR Spectroscopy of the Dried Hydrolyzed Solid ......................... 23 2.4.2 IR Measurements ............................................................................... 24

2.5 General Discussion ........................................................................................ 27 Acknowledgments.................................................................................................... 29 References................................................................................................................ 29

Alumina prepared by conventional hydrolysis of aluminum compound precursors is covered by surface hydroxyl groups. High-temperature calcination is needed in order to expose the surface coordination unsaturation of Al ions. A new method, which involves stoichiometric hydrolysis of an amine-Al alkoxide monomeric complex, can generate alumina with a surface that is covered with far fewer hydroxyls without high-temperature postsynthesis treatment. In this method, the coordination unsaturation site of Al is protected with an amine throughout the preparation process. The bound amine on the alumina surface can be exchanged with other bases, and the final solid is a Lewis-acid catalyst and catalyzes reactions such as aminolysis of epoxide. The chemistry in the preparation of such an alumina is described.