| abstract |
Thermally stable composite precipitates containing aluminum phosphate and alumina and having a surface area of from about 100 to about 200 m2/g together with an average pore radius of from 75 to 150 A are defined. These materials are prepared by neutralizing an aqueous solution of aluminum cations and PO4 anions at a controlled pH of between 7 and 10.0, and wherein the neutralizing medium is either ammonia or certain defined amine based materials such as ammonium hydroxide, ammonium carbonate or urea. There is a stoichiometric excess of aluminum to phosphorus over that required to form AlPO4. Due to their thermal stability these alumina-aluminum phosphates are particularly useful as catalyst supports for various reactions, including polymerization of ethylene. |