Catalysts with high cobalt surface area

Abstract

A catalyst or precursor thereto comprising cobalt and/or a cobalt compound on a transition alumina support having a total cobalt content of at least 41% by weight and a cobalt surface area, after reduction, greater than 25 m 2 per gram of total cobalt. The catalyst or precursor may be made by slurrying a transition alumina powder having a pore volume of at least 0.7 ml/g with an aqueous cobalt ammine carbonate complex and heating the slurry to decompose the complex.

1 . A particulate catalyst precursor comprising cobalt compounds supported on a transition alumina support and having a total cobalt content of 20 to 85% by weight, a pore volume above 0.3 ml/g, and a surface-weighted mean diameter D[3,2] in the range 1 μm to 200 μm and which, upon reduction, has a cobalt surface area of at least 25 m 2  per gram of total cobalt.  
     
     
         2 . A catalyst precursor according to  claim 1  having a total cobalt content above 40% by weight.  
     
     
         3 . A catalyst precursor according to  claim 1  having a pore volume above 0.5 ml/g.  
     
     
         4 . A catalyst precursor according to  claim 1  having a surface-weighted mean diameter D[3,2] below 20 μm.  
     
     
         5 . A catalyst precursor according to  claim 1  having an average pore diameter of at least 8 nm.  
     
     
         6 . A catalyst precursor according to  claim 1  wherein the cobalt is present as cobalt oxides.  
     
     
         7 . A catalyst precursor according to  claim 1  having a total cobalt content above 50% by weight and wherein the alumina is a gamma alumina.  
     
     
         8 . A particulate catalyst comprising cobalt supported on a transition alumina support and having a total cobalt content of 20 to 85% by weight, a pore volume above 0.3 ml/g, a surface-weighted mean diameter D[3,2] in the range 1 μm to 200 μm, and a cobalt surface area of at least 25 m 2  per gram of total cobalt.  
     
     
         9 . A catalyst according to  claim 8  having a total cobalt content above 40% by weight.  
     
     
         10 . A catalyst according to  claim 8  having a pore volume above 0.5 ml/g.  
     
     
         11 . A catalyst according to  claim 8  having a surface-weighted mean diameter D[3,2] below 20 μm.  
     
     
         12 . A catalyst according to  claim 8  having an average pore diameter of at least 8 nm.  
     
     
         13 . A catalyst according to  claim 8  having a total cobalt content above 50% by weight and wherein the alumina is a gamma alumina.  
     
     
         14 . A catalyst according to  claim 8  wherein at least 50% of the cobalt is present as metallic cobalt.  
     
     
         15 . A method of making a catalyst precursor containing 20 to 85% by weight of total cobalt comprising slurrying a transition alumina powder having a pore volume above 0.7 ml/g with an aqueous solution of a cobalt ammine complex, heating the slurry to cause the cobalt ammine complex to decompose with the deposition of an insoluble cobalt compound, filtering the solid residue from the aqueous medium and drying the solid residue.  
     
     
         16 . A method according to  claim 15  wherein the slurry is heated for a period of not more than 200 minutes to cause the cobalt ammine complex to decompose.  
     
     
         17 . A method according to  claim 15  wherein the alumina powder has a surface-weighted mean diameter D[3,2] in the range 1 μm to 200 μm.  
     
     
         18 . A method according to  claim 15  wherein the transition alumina powder has a surface-weighted mean diameter D[3,2] below 20 μm.  
     
     
         19 . A method according to  claim 15 , wherein the transition alumina powder has an average pore diameter of at least 10 nm.