A carbon molecular sieve (CMS) membrane having improved separation characteristics for separating olefins from their corresponding paraffins is comprised of carbon with at most trace amounts of sulfur and a group 13 metal. The CMS membrane may be made by pyrolyzing a precursor polymer devoid of sulfur in which the precursor polymer has had a group 13 metal incorporated into it, wherein the metal is in a reduced state. The pyrolyzing for the precursor having the group 13 metal incorporated into it is performed in a nonoxidizing atmosphere and at a heating rate and temperature such that the metal in a reduced state (e.g., covalently bonded to carbon or nitrogen or in the metal state).

A membrane separator comprising a membrane is used to separate various streams in processes for separating aromatic hydrocarbons from non-aromatic hydrocarbons. Such streams can be a lean-solvent stream, a rich-solvent stream, or a hydrocarbon stream comprising both aromatic and non- aromatic hydrocarbons. The membrane separator is advantageously used in combination with an extraction sub-system including a liquid—liquid distillation column and/or an extraction distillation column.

A membrane separator comprising a membrane is used to separate various streams in processes for separating aromatic hydrocarbons from non-aromatic hydrocarbons. Such streams can be a lean-solvent stream, a rich-solvent stream, or a hydrocarbon stream comprising both aromatic and non- aromatic hydrocarbons. The membrane separator is advantageously used in combination with an extraction sub-system including a liquid—liquid distillation column and/or an extraction distillation column.

A membrane separator comprising a membrane is used to separate various streams in processes for separating aromatic hydrocarbons from non-aromatic hydrocarbons. Such streams can be a lean-solvent stream, a rich-solvent stream, or a hydrocarbon stream comprising both aromatic and non- aromatic hydrocarbons. The membrane separator is advantageously used in combination with an extraction sub-system including a liquid—liquid distillation column and/or an extraction distillation column.

The extraction of benzene from benzene/cyclohexane mixture described herein is a process that removes benzene from a benzene/cyclohexane mixture with high selectivity, resulting in an enriched cyclohexane content in the retentate. The process involves adding an aqueous solution of poloxamer 188 to the benzene/cyclohexane mixture and waiting for the mixture to partition into an organic layer above an aqueous layer. Benzene, being more polar than cyclohexane, is selectively drawn into the aqueous layer. Benzene is then removed from the aqueous layer by pervaporation through a composite PDMS (polydimethylsiloxane)/polystyrene membrane. Cyclohexane is recovered from the retentate by drawing off the organic layer of the retentate by any known method. About 97% of benzene has been removed from a 50-50 wt % mixture by pervaporation in the static mode, and about 99% by pervaporation in the continuous mode.

The extraction of benzene from benzene/cyclohexane mixture described herein is a process that removes benzene from a benzene/cyclohexane mixture with high selectivity, resulting in an enriched cyclohexane content in the retentate. The process involves adding an aqueous solution of poloxamer 188 to the benzene/cyclohexane mixture and waiting for the mixture to partition into an organic layer above an aqueous layer. Benzene, being more polar than cyclohexane, is selectively drawn into the aqueous layer. Benzene is then removed from the aqueous layer by pervaporation through a composite PDMS (polydimethylsiloxane)/polystyrene membrane. Cyclohexane is recovered from the retentate by drawing off the organic layer of the retentate by any known method. About 97% of benzene has been removed from a 50-50 wt % mixture by pervaporation in the static mode, and about 99% by pervaporation in the continuous mode.

The extraction of benzene from benzene/cyclohexane mixture described herein is a process that removes benzene from a benzene/cyclohexane mixture with high selectivity, resulting in an enriched cyclohexane content in the retentate. The process involves adding an aqueous solution of poloxamer 188 to the benzene/cyclohexane mixture and waiting for the mixture to partition into an organic layer above an aqueous layer. Benzene, being more polar than cyclohexane, is selectively drawn into the aqueous layer. Benzene is then removed from the aqueous layer by pervaporation through a composite PDMS (polydimethylsiloxane)/polystyrene membrane. Cyclohexane is recovered from the retentate by drawing off the organic layer of the retentate by any known method. About 97% of benzene has been removed from a 50-50 wt % mixture by pervaporation in the static mode, and about 99% by pervaporation in the continuous mode.

A separation method includes a separation step of using a zeolite membrane composite to separate a branched diolefin from a branched hydrocarbon mixture containing the branched diolefin and at least one branched hydrocarbon in which the number of carbon-carbon double bonds is 1 or less and that is of an equivalent carbon number n to the branched diolefin. The zeolite membrane composite used in this step is a zeolite membrane composite that includes a porous support and a FAU-type zeolite membrane formed on at least one surface of the porous support, and in which the FAU-type zeolite membrane is a silylated FAU-type zeolite membrane including a silyl group at the surface thereof.

A separation method includes a separation step of using a zeolite membrane composite to separate a branched diolefin from a branched hydrocarbon mixture containing the branched diolefin and at least one branched hydrocarbon in which the number of carbon-carbon double bonds is 1 or less and that is of an equivalent carbon number n to the branched diolefin. The zeolite membrane composite used in this step is a zeolite membrane composite that includes a porous support and a FAU-type zeolite membrane formed on at least one surface of the porous support, and in which the FAU-type zeolite membrane is a silylated FAU-type zeolite membrane including a silyl group at the surface thereof.

A separation method includes a separation step of using a zeolite membrane composite to separate a branched diolefin from a branched hydrocarbon mixture containing the branched diolefin and at least one branched hydrocarbon in which the number of carbon-carbon double bonds is 1 or less and that is of an equivalent carbon number n to the branched diolefin. The zeolite membrane composite used in this step is a zeolite membrane composite that includes a porous support and a FAU-type zeolite membrane formed on at least one surface of the porous support, and in which the FAU-type zeolite membrane is a silylated FAU-type zeolite membrane including a silyl group at the surface thereof.