Eastman Chemical Company

Keith B Terhune

Kevin John Fontenot

David Carl Attride

The invention relates to a process for isolating a phenyl ester salt from a mixture comprising sulfolane (tetrahydrothiophene-1,1-dioxide). The invention includes adjusting the temperature of a mixture comprising a phenyl ester salt and sulfolane to a temperature of about 100-150&deg; C. This step leads to the formation of a mixture comprising a solid phenyl ester salt and sulfolane. Next, the solid phenyl ester salt is separated, while maintaining the temperature of the mixture at about 100-150&deg; C. The invention also relates to a process that includes adding a sufficient amount of a solvent to a mixture comprising a phenyl ester salt and sulfolane to decrease the viscosity or the density of the mixture. The solvent added has a density less than about 1.20 g/cm at 100&deg; C. or a viscosity of less than about 2.56 centipoise at 100&deg; C. The embodiments of the invention may be used alone or in combination. This invention may be used for the isolation of a variety of phenyl ester salts, including but not limited to sodium 4-sulfophenyl-6-&lsqb;(1-oxynonyl)amino&rsqb;hexanoate, sodium 4-(nonanoyloxy) benzenesulfonate, and sodium benzoyloxybenzenesulphonate.

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Batesville, AR, United States of America

Keith B Terhune