Patent ID: 6555726
Filing Date: 2003-04-29
Classification: C07C

Abstract:
A process for separating hydrocarbon compounds of similar boiling points by extractive distillation, comprising the steps of:a) contacting a feed mixture with an extractive distillation composition within an extractive distillation zone, wherein the feed mixture comprises at least i) a first hydrocarbon compound, and ii) a second hydrocarbon compound comprising an aromatic residue; and b) distilling the feed mixture to at least partially separate the feed mixture into an overhead stream enriched in the first hydrocarbon compound, and a bottoms stream enriched in the second hydrocarbon compound; and wherein the extractive distillation composition comprises i) sulfolane and/or a sulfolane derivative having the formula: wherein S1, S2, S3, and S4 are independently hydrogen or an alkyl having one to six carbon atoms, andii) at least one compatibility agent, wherein the at least one compatibility agent: (1) has a Hansen's Solubility Polar Parameter from about 2.7 to about 6.4 (calories/cm3)Â½, and a Hansen's Solubility Hydrogen Bonding Parameter from about 1.0 to about 4.4 (calories/cm3)Â½: (2) has a boiling point higher than the boiling point of the mixture of hydrocarbon compounds; and (3) does not comprise an N-substituted-2-thiopyrrolidone compound or residue.