Patent GB-682157-A (GB)
Title: Improvements in or relating to the separation of mixtures comprising hydrocarbons
IPC: C10G21/22
Filed: 1948-06-08
Abstract: Mixtures comprising at least two hydrocarbons are separated into two fractions, one enriched in one hydrocarbon and the other enriched in another hydrocarbon, by solvent extraction or extractive distillation using a solvent comprising pentamethylene sulphone and/or a mono- or poly-methyl substitution derivative thereof, with or without tetramethylene sulphone and/or a mono- or polymethyl substitution derivative thereof or other solvent materials.  The process is applicable to the separation of paraffins from naphthenes, naphthenes from aromatics, paraffins from olefins and mono-olefins from dienes, but may also be employed in the extraction of aromatic concentrates from petroleum distillates.  In the examples, a benzine cut of petroleum, which cut contains paraffins, naphthenes and aromatics, is subjected to solvent extraction to separate an aromatic-enriched extract phase from a raffinate phase enriched in paraffins and naphthenes.  The solvent employed in these examples comprises either a mixture of pentamethylene sulphone and mono-methyl pentamethylene sulphone or a mixture of polymethyl tetramethylene sulphones and polymethyl pentamethylene sulphones, but for comparison purposes the use of a solvent comprising tetramethylene sulphone and monomethyl tetramethylene sulphones is described.  The various mixtures comprising sulphones employed as solvents in the examples are all prepared by oxidation of various sulphur missing pages number 53 to 56ALSO:Mixtures comprising at least two hydrocarbons are separated into two fractions, one enriched in one hydrocarbon and the other enriched in another hydrocarbon, by solvent extraction or extractive distillation using a solvent comprising pentamethylene sulphone and/or a mono- or poly-methyl substitution derivative thereof, with or without tetramethylene sulphone and/or a mono- or poly-methyl substitution derivative thereof or other solvent materials.  The process is applicable to the separation of paraffins from naphthenes, naphthenes from aromatics, paraffins from olefins and mono-olefins from dienes, but may also be employed in the refining of hydrocarbon lubricating oils and in the extraction of aromatic concentrates from petroleum distillates.  In the example, a benzine cut of petroleum, which cut contains paraffins, naphthenes and aromatics, is subjected to solvent extraction to separate an aromatic-enriched extract phase from a raffinate phase enriched in paraffins and naphthenes.  The solvent employed in these examples comprises either a mixture of pentamethylene sulphone and mono-methyl pentamethylene sulphone or a mixture of polymethyl tetramethylene sulphones and polymethyl pentamethylene sulphones but for comparison purposes the use of a solvent comprising tetramethylene sulphone and mono-methyl tetramethylene sulphones is described.  The various mixtures comprising sulphones employed as solvents in the examples are all prepared by oxidation of various sulphur-containing fractions obtained from straight-run benzine (see Group IV (b)).  According to the Provisional Specification the solvent may comprise a polymethylene sulphone or a mono- or polymethyl substitution derivative thereof or may comprise a dehydro derivative of pentamethylene sulphone or of a mono- or poly-methyl substitution derivative of pentamethylene sulphone.  The solvents may also, according to the Provisional Specification, be employed in the separation of sulphur-containing compounds from hydrocarbons as in the desulphurization of petroleum fractions.  Specifications 625,505 and 654,464, [Group IV (b)], are referred to