In a process for producing para-xylene, a feed stream comprising C.sub.6+ aromatic hydrocarbons is separated into a toluene-containing stream, a C.sub.8 aromatic hydrocarbon-containing stream and a C.sub.9+ aromatic hydrocarbon-containing stream. The toluene-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the C.sub.8 aromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C.sub.9+-containing stream with a transalkylation catalyst under conditions effective to convert C.sub.9+-aromatics to C.sub.8−-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

In a process for producing para-xylene, a feed stream comprising C.sub.6+ aromatic hydrocarbons is separated into a toluene-containing stream, a C.sub.8 aromatic hydrocarbon-containing stream and a C.sub.9+ aromatic hydrocarbon-containing stream. The toluene-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the C.sub.8 aromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C.sub.9+-containing stream with a transalkylation catalyst under conditions effective to convert C.sub.9+-aromatics to C.sub.8−-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

The invention relates to a p-xylene separation process wherein at least a portion of ethylbenzene present in an aromatics-containing feed is removed prior to isomerization. Aspects of the invention provide a process for producing p-xylene. The process includes providing a first mixture comprising ≧5.0 wt. % of aromatic C.sub.8 isomers, the C.sub.8 isomers comprising p-xylene and ethylbenzene. A p-xylene-containing portion and an ethylbenzene-containing portion are separated from the first mixture in a first separation stage to form a p-xylene-depleted raffinate. The first separation stage can include at least one simulated moving-bed adsorptive separation stage. At least a portion the p-xylene-depleted raffinate in the liquid phase is reacted to produce a reactor effluent comprising aromatic C.sub.8 isomers. The first mixture can be combined with ≧50.0 wt. % of the reactor effluent's aromatic C.sub.8 isomers. The combining can be carried out before and/or during the separating of the p-xylene and ethylbenzene portions.

The invention relates to a p-xylene separation process wherein at least a portion of ethylbenzene present in an aromatics-containing feed is removed prior to isomerization. Aspects of the invention provide a process for producing p-xylene. The process includes providing a first mixture comprising ≧5.0 wt. % of aromatic C.sub.8 isomers, the C.sub.8 isomers comprising p-xylene and ethylbenzene. A p-xylene-containing portion and an ethylbenzene-containing portion are separated from the first mixture in a first separation stage to form a p-xylene-depleted raffinate. The first separation stage can include at least one simulated moving-bed adsorptive separation stage. At least a portion the p-xylene-depleted raffinate in the liquid phase is reacted to produce a reactor effluent comprising aromatic C.sub.8 isomers. The first mixture can be combined with ≧50.0 wt. % of the reactor effluent's aromatic C.sub.8 isomers. The combining can be carried out before and/or during the separating of the p-xylene and ethylbenzene portions.

Embodiments of zeolite composite catalysts and methods of producing the zeolite composite catalysts are provided, where the methods comprise dissolving in an alkaline solution a catalyst precursor comprising at least one mesoporous zeolite while heating, stirring, or both to yield a dissolved zeolite solution, where the mesoporous zeolite has a molar ratio of SiO.sub.2/Al.sub.2O.sub.3 of at least 30, where the mesoporous zeolite comprises zeolite beta, adjusting the pH of the dissolved zeolite solution, aging the pH adjusted dissolved zeolite solution to yield solid zeolite composite from the dissolved zeolite solution, and calcining the solid zeolite composite to produce the zeolite composite catalyst, where the zeolite composite catalyst has a mesostructure comprising at least one disordered mesophase and at least one ordered mesophase, and where the zeolite composite catalyst has a surface area defined by the Brunauer-Emmett-Teller (BET) analysis of at least 600 m.sup.2/g.

Embodiments of zeolite composite catalysts and methods of producing the zeolite composite catalysts are provided, where the methods comprise dissolving in an alkaline solution a catalyst precursor comprising at least one mesoporous zeolite while heating, stirring, or both to yield a dissolved zeolite solution, where the mesoporous zeolite has a molar ratio of SiO.sub.2/Al.sub.2O.sub.3 of at least 30, where the mesoporous zeolite comprises zeolite beta, adjusting the pH of the dissolved zeolite solution, aging the pH adjusted dissolved zeolite solution to yield solid zeolite composite from the dissolved zeolite solution, and calcining the solid zeolite composite to produce the zeolite composite catalyst, where the zeolite composite catalyst has a mesostructure comprising at least one disordered mesophase and at least one ordered mesophase, and where the zeolite composite catalyst has a surface area defined by the Brunauer-Emmett-Teller (BET) analysis of at least 600 m.sup.2/g.

The present disclosure provides compositions and methods for metathesizing a first alkenyl or alkynyl group with a second alkenyl or alkynyl group, the composition comprising a ruthenium metathesis catalyst and a photo-redox catalyst that is activated by infrared light.

The present disclosure provides compositions and methods for metathesizing a first alkenyl or alkynyl group with a second alkenyl or alkynyl group, the composition comprising a ruthenium metathesis catalyst and a photo-redox catalyst that is activated by infrared light.

The present disclosure provides compositions and methods for metathesizing a first alkenyl or alkynyl group with a second alkenyl or alkynyl group, the composition comprising a ruthenium metathesis catalyst and a photoredox catalyst that is activated by visible light.

The present disclosure provides compositions and methods for metathesizing a first alkenyl or alkynyl group with a second alkenyl or alkynyl group, the composition comprising a ruthenium metathesis catalyst and a photoredox catalyst that is activated by visible light.