Transalkylation of heavy aromatic hydrocarbon feedstocks

A catalyst system comprising:

• (a) a first catalyst bed comprising (i) a first molecular sieve having a Constraint Index in the range of about 3 to about 12 and (ii) at least one metal selected from platinum, palladium, iridium, and rhenium, in an amount between about 0.001 and about 5 wt % of the first catalyst, and at least one metal selected from copper, silver, gold, ruthenium, iron, tungsten, molybdenum, cobalt, nickel, tin and zinc, in an amount between about 0.001 and about 10 wt % of the first catalyst;
• and
• (b) a second catalyst bed comprising (i) a second molecular sieve having a Constraint Index less than 3 and (ii) at least one metal selected from platinum, palladium, iridium, and rhenium, in an amount between about 0.001 and about 5 wt % of the second catalyst, and at least one metal selected from copper, silver, gold, ruthenium, iron, tungsten, molybdenum, cobalt, nickel, tin and zinc, in an amount between about 0.001 and about 10 wt % of the second catalyst;
• wherein the weight ratio of said first catalyst to said second catalyst is in the range of about 5:95 to about 75:25 and wherein said first catalyst bed is located upstream of said second catalyst bed when the catalyst system is brought into contact with said C9+ aromatic hydrocarbon feedstock and said C6-C7 aromatic hydrocarbon in the presence of hydrogen;
• (c) a third catalyst bed comprising a third molecular sieve having a Constraint Index in the range of about 3 to about 12,
• said catalyst system further characterized as comprising, in series, said first catalyst bed, then said second catalyst bed, then said third catalyst bed.