Patent ID: 9248381
Filing Date: 2016-02-02
CPC Classification: B01D,C07C

Claim Text:
1. A process for purifying a dicarboxylic acid comprising: a) ozonizing a mixture comprising an ethylenically unsaturated compound having between 6 to 24 carbons with an ozone-containing gas to form a plurality of ozonization products; b) cleaving the plurality of ozonization products under oxidative conditions in the presence of a suitable catalyst to form mixed oxidation products, wherein the mixed oxidation products comprise a mixture of C2 to C22 monocarboxylic acids and C2 to C22 dicarboxylic acids that includes the dicarboxylic acid; c) distilling the mixed oxidation products to provide a first distillate comprising a portion of the C2 to C22 monocarboxylic acids, and a first residue of the mixed oxidation products, wherein the first residue of the mixed oxidation products comprises the dicarboxylic acid and a plurality of impurity acids; d) distilling the first residue of the mixed oxidation products to provide a second distillate and a second residue of the mixed oxidation products, wherein the second distillate comprises the dicarboxylic acid and a first fraction of the plurality of impurity acids; (e) partitioning the second distillate between water and an organic solvent, wherein the water is at a temperature within the range of about 175° F., 79° C. to about 230° F., 110° C.; wherein water and the organic solvent are substantially immiscible to thereby form an aqueous layer containing the dicarboxylic acid and an organic solvent layer containing a second fraction of the plurality of impurity acids; f) separating the organic solvent layer from the aqueous layer; g) lowering the temperature of the aqueous layer to crystallize at least a portion of the dicarboxylic acid from the aqueous layer to provide a crystallized dicarboxylic acid solid and a mother liquor containing uncrystallized dicarboxylic acid and a major portion of a third fraction of the plurality of impurity acids; h) separating the crystallized dicarboxylic acid solid from the mother liquor to provide a first batch of the dicarboxylic acid comprising the crystallized dicarboxylic acid solid; i) melting the first batch of the dicarboxylic acid to form a liquid comprising the dicarboxylic acid; and j) distilling the liquid comprising the dicarboxylic acid to provide a purified dicarboxylic acid.