A process for producing xylenes, in particular para-xylene that is less energy intensive than conventional processes is provided. In an embodiment the process comprises contacting a feed mixture in an isomerization zone with a catalyst at isomerization conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomerization can also be coupled with a p-xylene extraction process, where the raffinate (p-xylene deprived stream) from the extraction process is fed to an isomerization reactor to produce p-xylene. In an embodiment, the process can comprise: a) providing a feed stream comprising a mixture of xylene isomers including p-xylene; b) extracting p-xylene from the feed stream using a separator to separate the feed stream into a p-xylene rich stream and a p-xylene deprived stream; and c) delivering the p-xylene deprived stream to an isomerization unit, the isomerization unit including an acidic sulfonated catalytic membrane, and using the isomerization unit to produce an isomerized product comprising a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomerization unit. In any one or more aspects, the isomerization unit can be operated at a temperature in the range of less than 350°, for example about 20° C. to about 200° C.

A process for producing xylenes, in particular para-xylene that is less energy intensive than conventional processes is provided. In an embodiment the process comprises contacting a feed mixture in an isomerization zone with a catalyst at isomerization conditions and producing an isomerized product comprising a higher proportion of p-xylene than in the feed mixture, wherein the catalyst comprises an acidic sulfonated catalytic membrane. Xylene isomerization can also be coupled with a p-xylene extraction process, where the raffinate (p-xylene deprived stream) from the extraction process is fed to an isomerization reactor to produce p-xylene. In an embodiment, the process can comprise: a) providing a feed stream comprising a mixture of xylene isomers including p-xylene; b) extracting p-xylene from the feed stream using a separator to separate the feed stream into a p-xylene rich stream and a p-xylene deprived stream; and c) delivering the p-xylene deprived stream to an isomerization unit, the isomerization unit including an acidic sulfonated catalytic membrane, and using the isomerization unit to produce an isomerized product comprising a higher proportion of p-xylene than in the p-xylene deprived stream delivered to the isomerization unit. In any one or more aspects, the isomerization unit can be operated at a temperature in the range of less than 350, for example about 20 C. to about 200 C.

A flexible process for gasoline refineries is described. The process can vary depending on the available feedstock and the desired products. At one time, the process can involve disproportionating pentanes to a product mixture including isobutane and isohexane. At other times, by switching the feedstock and operating conditions, the process can convert a mixture of C.sub.4 and C.sub.7 paraffins to a low aromatic blendstock with suitable octane and a vapor pressure lower than butanes. The process can be performed in separate stand-alone units operated at different times, or a single unit can be operated according to one process at one time and according to the other process at another time.

A flexible process for gasoline refineries is described. The process can vary depending on the available feedstock and the desired products. At one time, the process can involve disproportionating pentanes to a product mixture including isobutane and isohexane. At other times, by switching the feedstock and operating conditions, the process can convert a mixture of C.sub.4 and C.sub.7 paraffins to a low aromatic blendstock with suitable octane and a vapor pressure lower than butanes. The process can be performed in separate stand-alone units operated at different times, or a single unit can be operated according to one process at one time and according to the other process at another time.