had contained sodium at least 18 wt barium and up to 28 wt barium is incorporated into the zeolite structure 13x zeolite with a silica to alumina ratio of 5 is mixed with a saturated manganese nitrate solution and heated to 80 u00b0 c for 4 hours the solids are filtered then washed then calcined at 740 u00b0 c for 2 hours the process is repeated at least 2 more times the resulting material has manganese occupying sites that had contained sodium at least 21 wt manganese and up to 31 wt manganese is incorporated into the zeolite structure zsm 5 type zeolite support having a silica to alumina ratio of about 25 to about 80 a ratio of about 25 is preferred is mixed with an saturated nickel tetraamine solution and heated to 80 u00b0 c for 4 hours the solids are filtered then washed then calcined at 700 u00b0 c for 2 hours the resulting material has nickel occupying sites that had contained sodium at least 0 1 wt to about 2 0 wt is incorporated into the zeolite structure zsm 5 type zeolite support having a silica to alumina ratio of about 25 to about 80 a ratio of about 80 is preferred is mixed with an saturated palladium tetraamine solution and heated to 80 u00b0 c for 4 hours the solids are filtered then washed then calcined at 700 u00b0 c for 2 hours the resulting material.