Membrane solvent extraction process

Abstract

The instant invention relates to a membrane solvent extraction and reaction system. More particularly it pertains to an improvement in the membrane solvent extraction system wherein a solute is extracted through a polymeric membrane from one solvent liquid phase to an extracting solvent liquid without direct contact between the liquid phases which are separated by the membrane and in which the extracting solvent has no greater solubility and usually substantially less solubility for the solute than the feed solvent. The impovement comprises converting the solute permeating across the membrane to a different chemical compound, whereby a high concentration gradient for the solute across the membrane is maintained to improve the separation of the solute from the feed solvent liquid phase. This improved process is particularly useful for the separation of partially oxygenated hydrocarbons from admixture with hydrocarbons and conversion of the permeating oxygenated hydrocarbons by oxidation in an extracting aqueous solvent containing an oxidizing agent, and in which extracting solvent the oxygenated hydrocarbon solute is less soluble than in the hydrocarbon solvent. This process is especially useful for the separation of the oxidation products of cyclohexane, e.g., cyclohexanol and cyclohexanone, by permeation through a hydrophilic membrane, e.g., fluorocarbon polymers containing pendant sulfonic acid and/or carboxylic acid groups and the salts thereof, into an aqueous solvent comprising an oxidant, e.g., nitric acid. In this embodiment, the oxidation products of cyclohexane may be continuously separated from unoxidized cyclohexane and converted into adipic acid.

Dependencies are inferred from the claim text.