A process is described for preparing a catalyst comprising at least one zeolite with a modified EUO structure type, at least one matrix and at least one metal from group VIII of the periodic classification of the elements. Said catalyst is used in a process for the isomerization of an aromatic feed comprising at least one compound containing eight carbon atoms per molecule.

Disclosed are processes for conversion of a feedstock comprising C.sub.8+ aromatic hydrocarbons to lighter aromatic products in which the feedstock and optionally hydrogen are contacted in the presence of the catalyst composition under conversion conditions effective to dealkylate and transalkylate said C.sub.8+ aromatic hydrocarbons to produce said lighter aromatic products comprising benzene, toluene and xylene. The catalyst composition comprises a zeolite, a first metal, and a second metal, and is treated with a source of sulfur and/or a source of steam.

Disclosed are processes for conversion of a feedstock comprising C.sub.8+ aromatic hydrocarbons to lighter aromatic products in which the feedstock and optionally hydrogen are contacted in the presence of a first and a second catalyst composition under conversion conditions effective to produce said lighter aromatic products comprising benzene, toluene and xylene. In the process, the C.sub.8+ aromatic hydrocarbons are dealkylated to form C.sub.6-C.sub.7 aromatic hydrocarbon and the C.sub.2+ olefins formed are saturated. The remaining C.sub.8+ aromatic hydrocarbons are transalkylated with the C.sub.6-C.sub.7 aromatic hydrocarbon. The first and second catalyst compositions each comprise a zeolite, a first metal, and optionally a second metal, and are treated with a source of sulfur and/or a source of steam.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a first zeolite having a constraint index of 3 to 12, a second zeolite comprising a mordenite zeolite synthesized from TEA or MTEA, at least one first metal of Group 10 of the IUPAC Periodic Table, and at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

A hydroisomerization catalyst comprising a molecular sieve belonging to the ZSM-48 family of zeolites; an inorganic oxide support; one or more first modifiers selected from Groups 8 to 10; and one or more second modifiers selected from the group consisting of calcium (Ca), chromium (Cr), magnesium (Mg), lanthanum (La), barium (Ba), praseodymium (Pr), strontium (Sr), potassium (K) and neodymium (Nd). The molecular sieve comprises: a silicon oxide to aluminum oxide mole ratio of about 40 to about 220; at least about 70% polytype 6 of the total ZSM-48-type material present in the product; and an additional EUO-type molecular sieve phase in an amount of between about 0 and about 7.0 percent by weight of the total product. The molecular sieve has a morphology characterized as polycrystalline aggregates comprising crystallites collectively having an average aspect ratio of between about 1 and about 8.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a mordenite zeolite synthesized from TEA or MTEA, optionally at least one first metal of Group 10 of the IUPAC Periodic Table, and optionally at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

Disclosed are a catalyst system and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst system comprises (a) a first catalyst bed comprising a first catalyst composition, said first catalyst composition comprising a zeolite having a constraint index of 3 to 12 combined (i) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (ii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table; and (b) a second catalyst bed comprising a second catalyst composition, said second catalyst composition comprising (i) a meso-mordenite zeolite, combined (ii) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (iii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said meso-mordenite zeolite is synthesized from TEA or MTEA and having a mesopore surface area of greater than 30 m.sup.2/g and said meso-mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

Disclosed are a catalyst system and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst system comprises (a) a first catalyst bed comprising a first catalyst composition, said first catalyst composition comprising a zeolite having a constraint index of 3 to 12 combined (i) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (ii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table; and (b) a second catalyst bed comprising a second catalyst composition, said second catalyst composition comprising (i) a meso-mordenite zeolite, combined (ii) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (iii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said meso-mordenite zeolite is synthesized from TEA or MTEA and having a mesopore surface area of greater than 30 m.sup.2/g and said meso-mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.