Disclosed are a bifunctional catalyst and a preparation method therefor, the bifunctional catalyst being suitable to produce high-value aromatic hydrocarbons by subjecting alkylaromatic hydrocarbons to a disproportionation/transalkylation/dealkylation reaction while suppressing aromatic loss or subjecting C8 aromatic hydrocarbons to an isomerization reaction while suppressing xylene loss.

A modified UZM-14 zeolite is described. The modified UZM-14 zeolite has a Modification Factor of 6 or more. The modified UZM-14 zeolite may have one or more of: a Si/Al.sub.2 ratio of 14 to 30; a total pore volume in a range of 0.5 to 1.0 cc/g; at least 5% of a total pore volume being mesopores having a diameter of 10 nm of less; a cumulative pore volume of micropores and mesopores having a diameter of 100 Å or less of 0.25 cc/g or more; or a Collidine IR Bronsted acid site distribution greater than or equal to an area of 3/mg for a peak in a range of 1575 to 1700 cm.sup.−1 after desorption at 150° C. Processes of making the modified UZM-14 zeolite and transalkylation processes using the modified UZM-14 zeolite are also described.

A catalyst suitable for the conversion of aromatic hydrocarbons is described. The catalyst comprises UZM-54 zeolite; a mordenite zeolite; a binder comprising alumina, silica, or combinations, thereof; and a metal selected from one or more of: Groups VIB(6) VIIB(7), VIII(8-10) and IVA(14) of the Periodic Table. A process for transalkylation using the catalyst is also described.

A transalkylation process co-feeds benzene at a relatively high proportion with C9+ aromatics in a feed stream to a transalkylation reactor. At lower proportions (≤5 wt %) of benzene, ring loss is greater for benzene than toluene and ring loss is increased by increasing the proportion of benzene in the feed stream. When the benzene is co-fed in a proportion sufficiently greater than 5 weight percent of the feed stream, ring loss is unexpectedly reduced.

A method of producing a purified mixed xylene comprising: introducing toluene and methanol to an alkylation reactor; reacting the toluene and the methanol in the alkylation reactor to form a hydrocarbon stream comprising a first mixed xylene, wherein the alkylation reactor comprises an alkylation catalyst; separating the hydrocarbon stream into a toluene stream and a separated C.sub.8+ stream; introducing the toluene stream to a transalkylation reactor with a transalkylation catalyst to produce a transalkylated stream comprising a second mixed xylene; adding the transalkylated stream to the hydrocarbon stream; and separating a C.sub.8 product stream comprising the purified mixed xylene from the separated C.sub.8+ stream.

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.

A process for producing benzene and xylenes comprising introducing hydrocarbon liquid stream to hydroprocessor to yield first gas stream and hydrocarbon product (C.sub.5+); optionally introducing hydrocarbon product to first aromatics separating unit to produce saturated hydrocarbons (C.sub.5+) and first aromatics stream (C.sub.6+); feeding hydrocarbon product and/or saturated hydrocarbons to reformer to produce reformer product, second gas stream, and hydrogen stream; introducing reformer product to second aromatics separating unit to produce a non-aromatics recycle stream and second aromatics stream comprising C.sub.6+ aromatics; recycling non-aromatics recycle stream to reformer; introducing first aromatics stream and/or second aromatics stream to third aromatics separating unit to produce first C.sub.6 aromatics (benzene), C.sub.7 aromatics (toluene), C.sub.8 aromatics (xylenes&ethylbenzene), C.sub.9 aromatics, C.sub.10 aromatics, and C.sub.11+ aromatics; introducing C.sub.7 aromatics, C.sub.9 aromatics, C.sub.10 aromatics, or combinations thereof to disproportionation and transalkylation unit to yield third aromatics stream (benzene and xylenes); and conveying C.sub.11+ aromatics to hydroprocessor.

Disclosed are a catalyst and a preparation method therefor, the catalyst being able to maintain a high production yield of C8 aromatic hydrocarbons in the process of converting a feedstock containing alkyl aromatics to C8 aromatic hydrocarbons such as mixed xylene through disproportionation/transalkylation/dealkylation while reducing a content of ethylbenzene in the products.

Co-feeding sulfolane into a transalkylation reactor along with the aromatic hydrocarbon feed(s) can improve benzene purity of the benzene product stream produced from the transalkylation product mixture, especially at the beginning phase of a catalyst cycle.

A modified UZM-14 zeolite is described. The modified UZM-14 zeolite has a Modification Factor of 6 or more. The modified UZM-14 zeolite may have one or more of: a Si/Al.sub.2 ratio of 14 to 30; a total pore volume in a range of 0.5 to 1.0 cc/g; at least 5% of a total pore volume being mesopores having a diameter of 10 nm of less; a cumulative pore volume of micropores and mesopores having a diameter of 100 or less of 0.25 cc/g or more; or a Collidine IR Bronsted acid site distribution greater than or equal to an area of 3/mg for a peak in a range of 1575 to 1700 cm.sup.1 after desorption at 150 C. Processes of making the modified UZM-14 zeolite and transalkylation processes using the modified UZM-14 zeolite are also described.