We claim:
1. In a process for the preparation of cyclohexanone by the selective hydrogenation of phenol in the vapor phase, the improvement which comprises carrying out the hydrogenation in the presence of a palladium catalyst on an aluminum spinel carrier obtained by annealing alumina with compounds of monovalent or divalent spinel forming metals followed by impregnation of the thus formed spinel carrier with a palladium salt which is subsequently reduced to the metal, said catalyst containing 0.1 to 10% by weight palladium.
2. Process of claim 1, carried out at 100°C to 350°C.
3. Process of claim 1, carried out at normal, reduced or elevated pressure.
4. Process of claim 1 wherein said spinel forming metals are selected from the group of lithium, magnesium, nickel, cobalt, mangenese and zinc.
5. Process of claim 1 wherein the amount of spinel formation in said carrier is at least 20%.
6. Process of claim 1 wherein said spinel carrier is formed from highly active alumina in the form of lumps having an internal surface area of 200-350 m2 /g.
7. Process of claim 1 wherein said spinel carrier has average 4 diameters of from 200-800 A.
8. Process of claim 1 wherein said spinel carrier has an internal surface area of from 20-120 m2 /g.
9. Process of claim 1 wherein the amount of palladium on said carrier is in the range of 0.1-10 percent by weigh