u03b3 al 2 o 3 support was impregnated in the solution aged for 12 hours dried for 4 hours at 200 u00b0 c and calcinated for 3 5 hours at 400 u00b0 c to obtain a catalyst c to 300 g of modified u03b3 al 2 o 3 powder 8 4 ml of phosphoric acid and 140 ml of water were added blended and extruded into a strip dried in the air at 120 u00b0 c and calcinated for 6 hours at 560 u00b0 c to obtain a modified u03b3 al 2 o 3 support containing phosphorus at 25 u00b0 c to a mixed solution of 50 ml of aqueous ammonia and 9 ml of triethylenetetramine 28 01 g of cobalt acetate was added and dissolved under stirring then 14 21 g of ammonium molybdate and 18 8 g of ammonium metatungstate were added and dissolved under stirring followed by addition of aqueous ammonia to adjust the volume of the solution to 95 ml 100 g of modified u03b3 al 2 o 3 support containing phosphorus was impregnated in the solution aged for 12 hours dried for 5 hours at 100 u00b0 c and calcinated for 5 hours at 350 u00b0 c to obtain a catalyst d at 30 u00b0 c to 60 ml of aqueous ammonia 14 21 g of cobalt acetate was added.