Process for preparing sulfonated arylphosphines
An aqueous catalyst solution comprising rhodium and an aqueous solution comprising sulfonated arylphosphines by reacting arylphosphines with oleum to form a sulfonation mixture, diluting the sulfonation mixture with water, extracting the diluted sulfonation mixture with a solution of a water-insoluble amine in a water-insoluble organic solvent, reacting the resulting water-immiscible organic phase with a solution of an inorganic base in water, adjusting the resulting aqueous solution of sulfonated arylphosphines of pH of up to 3 by addition of an acid, and passing an inert gas stream through the aqueous solution comprising sulfonated arylphosphines until sulfur dioxide is no longer liberated from the aqueous solution of sulfonated arylphosphines.
1 - 21 . (canceled)
22 . An aqueous catalyst solution comprising rhodium and an aqueous solution comprising sulfonated arylphosphines by reacting arylphosphines with oleum to form a sulfonation mixture, diluting the sulfonation mixture with water, extracting the diluted sulfonation mixture with a solution of a water-insoluble amine in a water-insoluble organic solvent, reacting the resulting water-immiscible organic phase with a solution of an inorganic base in water, adjusting the resulting aqueous solution of sulfonated arylphosphines of pH of up to 3 by addition of an acid, and passing an inert gas stream through the aqueous solution comprising sulfonated arylphosphines until sulfur dioxide is no longer liberated from the aqueous solution of sulfonated arylphosphines.