Process for modifying the shape selectivity of a zeolite catalyst and use of the mofified catalyst

IN A PROCESS TO MODIFY THE SELECTIVITY OF A ZEOLITO ALUMINOSILICATE CATALYZER THAT HAS A MOLAR INDEX OF ALUMINUM SILICOS LESS THAN 500, THE CATALYST IS EXPOSED TO AT LEAST TWO SEQUENCES OF EX SITU SELECTIVATION, WHERE EACH OF THESE PASSES CONTACT THE CATALYST WITH A SELECTIVE AGENT, NORMALLY AN ORGANOSILICONE COMPOUND, IN A CARRIER AND SUBSEQUENTLY CALCINATE THE CATALYST.