Device and process for the conversion of a feedstock of aromatic compounds, in which the feedstock is treated notably by means of a fractionation train (4-7), a xylene separation unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO.sub.2 and H.sub.2; a reverse water gas shift RWGS reaction section (50) treats the pyrolysis gas and produces an RWGS gas enriched in CO and in water; a fermentation reaction section (52) treats the RWGS gas enriched in CO and in water, and produces ethanol.

The present invention relates to a catalyst for isomerization of alkylated aromatics such as mixed xylenes, using xylene isomerization catalyst particles including post-framework modified USY zeolite in which zirconium atoms and/or titanium atoms and/or hafnium atoms form a part of a framework of an ultra-stable Y-type zeolite.

A process and related system for producing para-xylene (PX). In an embodiment, the process includes (a) separating a feed stream comprising C.sub.6+ aromatic hydrocarbons into a toluene containing stream and a C.sub.8+ hydrocarbon containing stream and (b) contacting at least part of the toluene containing stream with a methylating agent in a methylation unit to convert toluene to xylenes and produce a methylated effluent stream. In addition, the process includes (c) recovering PX from the methylated effluent stream in (b) to produce a PX depleted stream and (d) transalkylating the PX depleted stream to produce a transalkylation effluent stream. The transalkylation effluent stream includes a higher concentration of toluene than the PX depleted stream. Further, the process includes (e) converting at least some ethylbenzene (EB) within the C.sub.8+ hydrocarbon containing stream into toluene and (f) flowing the toluene converted in (e) to the contacting in (b).

A process and related system for producing para-xylene (PX). In an embodiment, the process includes (a) separating a feed stream comprising C.sub.6+ aromatic hydrocarbons into a toluene containing stream and a C.sub.8+ hydrocarbon containing stream and (b) contacting at least part of the toluene containing stream with a methylating agent in a methylation unit to convert toluene to xylenes and produce a methylated effluent stream. In addition, the process includes (c) recovering PX from the methylated effluent stream in (b) to produce a PX depleted stream and (d) transalkylating the PX depleted stream to produce a transalkylation effluent stream. The transalkylation effluent stream includes a higher concentration of toluene than the PX depleted stream. Further, the process includes (e) converting at least some ethylbenzene (EB) within the C.sub.8+ hydrocarbon containing stream into toluene and (f) flowing the toluene converted in (e) to the contacting in (b).

Processes for making phenol and xylenes from a phenols-containing feed are described. The processes involve transalkylation of alkylphenols to form phenol and alkylbenzenes. The phenol is separated from the alkylbenzenes, and the alkylbenzenes may be separated into benzene, toluene, xylenes, and heavy alkylbenzene streams. The benzene stream may be recycled to the transalkylation reaction zone. The toluene may be sent to a disproportionation reaction zone, and the product is sent back to the aromatic separation zone. The toluene can also be recycled to the transalkylation zone. The xylenes are separated into a p-xylene stream and a mixed xylene stream comprising m-xylene and o-xylene. The mixed xylene stream is isomerized and the isomerized product is sent back to the aromatic separation zone. The heavy alkylbenzenes are dealkylated and separated, with the aromatic stream being recycled to the aromatic separation zone.

Processes for making phenol and xylenes from a phenols-containing feed are described. The processes involve transalkylation of alkylphenols to form phenol and alkylbenzenes. The phenol is separated from the alkylbenzenes, and the alkylbenzenes may be separated into benzene, toluene, xylenes, and heavy alkylbenzene streams. The benzene stream may be recycled to the transalkylation reaction zone. The toluene may be sent to a disproportionation reaction zone, and the product is sent back to the aromatic separation zone. The toluene can also be recycled to the transalkylation zone. The xylenes are separated into a p-xylene stream and a mixed xylene stream comprising m-xylene and o-xylene. The mixed xylene stream is isomerized and the isomerized product is sent back to the aromatic separation zone. The heavy alkylbenzenes are dealkylated and separated, with the aromatic stream being recycled to the aromatic separation zone.

A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt % of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt % of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.

A process for oxidizing methyl-substituted biphenyl compounds comprises contacting a mixture comprising isomers of at least one methyl-substituted biphenyl compound with a source of oxygen, wherein the mixture comprises at least 20 wt % of isomer(s) having a methyl group at a 2-position or a 3-position on at least one benzene ring and at least 50 wt % of isomer(s) having a methyl group at a 4-position on at least one benzene ring, wherein said percentages are based on the total weight of the at least one methylbiphenyl compound in the mixture.

A method for retrofitting a system for recovering paraxylene. The system is retrofitted with a pressure swing adsorption unit and a second isomerization reactor. The retrofit lowers the variable cost of the plant, while providing the opportunity to maintain existing equipment and furnace and refrigeration duty.

Processes are described for separating 3,4- and 4,4-dimethylbiphenyl from a mixture comprising at least 3,3-, 3,4- and 4,4-dimethylbiphenyl. In the processes, the mixture is cooled to produce a crystallization product comprising at least of the 4,4-dimethylbiphenyl from the feed mixture and a first mother liquor product. The first mother liquor product is distilled to produce a bottoms stream enriched in 4,4-dimethylbiphenyl as compared with the first mother liquor product and an overhead stream deficient in 4,4-dimethylbiphenyl as compared with the first mother liquor product. The overhead stream is then cooled to produce a second crystallization product comprising at least part of the 3,4-dimethylbiphenyl from the overhead stream and a second mother liquor product.