Hydroformylation process using catalyst comprising platinum group metal on support having separate alumina phase

In a process for the hydroformylation reaction of an aliphatic monoolefin hydrocarbon of 2 to about 16 carbon atoms in the liquid phase, the improvement which comprises conducting said hydroformylation reaction in contact with a catalyst composition which comprises a minor, catalytically effective amount of a noble metal selected from;

• the group consisting of rhodium, ruthenium, platinum, and palladium on a major amount of a solid, acidic, silica-based support of silica-alumina containing a separate phase of alumina, the total catalyst composition containing 0.001 to 1 weight per cent of said noble metal, said support being calcined and comprising 45 to 95 weight per cent amorphous acidic silica-alumina having a Cat-A activity of at least 20 and about 5 to 55 weight per cent of said separate phase of alumina, said alumina resulting from the calcination of a mixture of amorphous hydrous alumina, and alumina monohydrate, the total alumina content of said support being about 20 to 70 weight per cent, said support being prepared by mixing together a separate phase alumina hydrogel with a silica-alumina hydrogel, dewatering the mixture to provide a gel slurry of about 14 weight per cent solids, spray-drying said slurry, washing the spray-dried material, pelletting the washed material, and calcining the pellets at about 1350.degree.F. for about 3 hours to provide calcined particles, said support containing less than 1.5 weight per cent sodium, said reaction being conducted at a temperature of from about 100.degree. to 550.degree.C. at a pressure up to about 2500 psig at an hourly velocity of weight of aliphatic monoolefin hydrocarbon per weight of catalyst of from about 0.5 to about 10, the hydrogen to carbon monoxide mol ratio being from about 1:1 to about 5:1.