Flame hydrolysis of oxide supports

COLL 28

Dieter Kerner, Research, Development and Applied Technology, Research, Development and Applied Technology, Degussa AG, Aerosil & Silanes, Rodenbacher Chaussee 4, D-63457Hanau-Wolfgang, Germany
It is now sixty years after the invention of the flame hydrolysis of silicon tetrachloride to silicon dioxide (silica) by the Degussa chemist Harry Kloepfer. Still today, silica is the most prominent product made by flame hydrolysis with a great variety of applications, catalyst support being only one of them. The presentation will give a review of the principle of flame hydrolysis and its use for the production of pyrogenic oxides like silica, titania and alumina. Their properties will be discussed with emphasis on the use as catalyst supports. For this application, one important property is the relatively high purity compared to oxides made by other processes. Also, corresponding mixed oxides and doped oxides recently gained importance. A new approach is the flame reaction of organometallic compounds which gives access to almost all corresponding oxides of the periodic table of the elements. Quite often the oxide powders need further processing like granulation or pelletization to be used as catalyst support.