Patent ID: 6455462
Filing Date: 2002-09-24
Classification: B01J

Abstract:
A process for preparing a catalyst precursor, which process comprisessubjecting, in an initial treatment stage, a slurry comprising a porous oxidic catalyst support or carrier, an active catalyst component or its precursor, and water, to treatment at a temperature T1 where 60Â° C.&lE;T1&lE;95Â° C. and at a sub-atmospheric pressure P1 where P1 ranges from atmospheric pressure >P1&gE;20 kPa(a) when T1=60Â° C. to atmospheric pressure >P1&gE;83 kPa(a) when T1=95Â° C., such that impregnation of the support or carrier with the active catalyst component or its precursor and partial drying of the impregnated support or carrier occurs, with the initial treatment stage not continuing beyond a point where the impregnated carrier or support has a loss on ignition (LOI) which is less than 1.2 times its loss on ignition at incipient wetness (LOIiw); thereafter, in a subsequent treatment stage, subjecting the partially dried impregnated support or carrier to treatment at a temperature T2 and at a sub-atmospheric pressure P2 such that 60Â° C.2&lE;95Â° C. and T2>T1 and/or P2<20 kPa(a) and P21, thereby to obtain more vigorous drying of the impregnated support or carrier in the subsequent treatment stage than in the initial treatment stage, with a dried impregnated carrier or support thereby being produced; and calcining the dried impregnated carrier or support, to obtain the catalyst precursor.