| abstract |
Certain crystalline aluminum borate catalyst supports containing about 8-25 weight-percent of B2O3 are found to provide unusually stable and active catalysts for high-temperature chemical conversions, particularly exhaust gas conversion, when prepared by precalcining shaped composites of alumina and boria at temperatures between about 1250 DEG and 2600 DEG F, prior to the addition thereto of active metal or metals. Calcination at below 1250 DEG F is found to yield amorphous catalysts of inferior activity, while at temperatures above 2600 DEG F drastic reductions in surface area may occur. |