Cyclohexane extraction to remove chlorodibenzo-p-dioxins
OwnerDavid B. Hatcherinventor
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Abstract
Chlorodibenzo-p-dioxin impurities are removed from a polychlorophenol that contains at least one chlorodibenzo-p-dioxin as an impurity by preparing an aqueous solution of a water-soluble alkaline salt of the polychlorophenol, mixing the aqueous solution with cyclohexane to extract the dioxins therefrom, decanting the purified aqueous solution from the cyclohexane phase, neutralizing the purified aqueous solution to precipitate the purified polychlorophenol, and separating the precipitate.
Claims7
A method of removing chlorodibenzo-p-dioxin impurities from a water-soluble alkaline salt of a polychlorophenol that contains up to about two parts of at least one chlorodibenzo-p-dioxin per thousand parts of polychlorophenol, as an impurity, comprising the steps of preparing an aqueous solution of such a salt having a polychlorophenol content from about 0.5% to about 30%, at a temperature from room temperature to the boiling point of the solution, mixing the aqueous solution with one-tenth to ten times its volume of cyclohexane to extract the dioxins therefrom, and decanting the purified aqueous solution from the cyclohexane phase.
Dependencies are inferred from the claim text.