Process for the production of purified camphorsulfonic acid salts
AssigneeThe Upjohn Company
InventorDavid R. Buss
Life of this patent
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Abstract
A liquid ion exchange process for recovering a concentrated purified aqueous solution of a camphorsulfonic acid salt from a dilute impure solution of the same wherein the ion exchange medium is a liquid secondary amine and the pH of the mixture during the ion exchange is maintained at 3 - 6 by treating the mixture with a polyprotic acid having two pKs of less than 2.5.
Claims7
In a process of purifying an aqueous solution of a camphorsulfonic acid salt which comprises (a) mixing at a pH of 3-6 a dilute aqueous solution of the camphorsulfonic acid salt and a solution consisting of a water-immiscible organic solvent and a secondary amine that is liquid at room temperature, soluble in the organic water-immiscible solvent, and is ##STR3## wherein R is an aliphatic group having from 10 to 14 carbon atoms and R.sub.1, R.sub.2 and R.sub.3 are each alkyl and wherein the combined carbon atoms in R.sub.1, R.sub.2 and R.sub.3 total from 11 to 14, (b) separating the organic water-immiscible phase from the mixture, (c) mixing the organic water-immiscible phase with a volume of water that is less than half the original aqueous solution volume at a pH above 9 to form a second two-phase mixture, and (d) separating the aqueous phase from said two-phase mixture to provide a purified concentrated aqueous solution of the salt;
- the improvement consisting of sulfuric acid to control the pH of the mixture formed in Step (a).
In a process of recovering a purified aqueous solution of a camphorsulfonic acid salt from an impure dilute aqueous solution of said salt, said impurities comprising inorganic salts, which comprises (a) mixing at a pH of 3-6 an impure dilute aqueous solution of the camphorsulfonic acid salt and a solution consisting of a water-immiscible organic solvent and a secondary amine that is liquid at room temperature, soluble in the organic water-immiscible solvent, and is ##STR4## wherein R is an aliphatic group having from 10 to 14 carbon atoms and R.sub.1, R.sub.2 and R.sub.3 are each alkyl and wherein the combined carbon atoms in R.sub.1, R.sub.2 and R.sub.3 total from 11 to 14, (b) separating the organic water-immiscible phase from the mixture, (c) mixing the organic water-immiscible phase with a volume of water that is less than half the original aqueous solution volume at a pH above 9 to form a second two-phase mixture, and (d) separating the aqueous phase from said two-phase mixture to provide a purified concentrated aqueous solution of the salt;
- the improvement consisting of utilizing sulfuric acid to control the pH of the mixture formed in Step (a).
Dependencies are inferred from the claim text.