RECOVERY OF ORGANIC ACID USING A COMPLEX EXTRACTION SOLVENT
A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. An amine, C02 and a water immiscible solvent are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and the amine that is soluble in both an aqueous and a solvent phase. The complex is extracted into the solvent phase which is than distilled to recover the acid or an ester of the acid in a concentrated form.
1 . A method for the recovery of an organic acid from an aqueous salt solution, wherein the cation of the salt forms an insoluble carbonate salt, comprising:
a. introducing an amine, carbon dioxide and a solvent to the aqueous salt solution to form a mixture comprising an insoluble carbonate salt phase, an aqueous phase, a solvent phase and an acid/amine complex; and
b. recovering the acid from the solvent phase to form an acid-depleted solvent phase.
2 - 5 . (canceled)
6 . The method of claim 1 , wherein the amine is selected from the group consisting of tributylamine, dicyclohexyl methyl amine, di-isopropyl ethyl amine, and mixtures thereof.
7 - 9 . (canceled)
10 . The method of claim 1 , wherein the solvent is polar.
11 - 12 . (canceled)
13 . The method of claim 1 , wherein the solvent further comprises an enhancer.
14 - 16 . (canceled)
17 . The method of claim 1 , wherein the step of recovering comprises separating at least a portion of the solvent phase from at least a portion of the aqueous phase, wherein both the separated solvent phase and the separated aqueous phase comprise acid/amine complex.
18 . (canceled)
19 . The method of claim 17 , further comprising distilling acid from the separated solvent phase to produce an acid-containing distillate and a bottoms fraction.
20 - 42 . (canceled)
43 . The method of claim 1 , further comprising
combining the aqueous phase and the acid-depleted solvent phase, whereby acid/amine complex in the aqueous phase is transferred to the acid-depleted solvent phase to form an acid-depleted aqueous phase and an acid-enriched solvent phase.
44 . The method of claim 43 , further comprising separating the acid depleted aqueous phase and the acid-enriched solvent phase.
45 . The method of claim 44 , further comprising intruding the acid-enriched solvent phase to the aqueous salt solution.
46 - 80 . (canceled)
81 . A method for the recovery of an organic acid from an aqueous salt solution, wherein the cation of the salt forms an insoluble carbonate salt, comprising:
a. introducing an amine, carbon dioxide and a solvent to the aqueous salt solution in a first reactor stage to form a mixture comprising an insoluble carbonate salt phase, an aqueous phase, a solvent phase and an acid/amine complex;
b. recovering the acid from the solvent phase from the first reactor stage;
c. combining the aqueous phase from the first reactor stage with an acid-enriched solvent phase from a liquid-liquid extraction in a second reactor stage to form an aqueous phase and a solvent phase;
d. separating the aqueous phase from the second reactor stage and the solvent phase from the second reactor stage;
e. introducing the aqueous phase from the second reactor stage to the liquid-liquid extraction; and
f. introducing the solvent phase from the second reactor stage to the first reactor stage.
82 - 85 . (canceled)
86 . The method of claim 81 , wherein the amine is selected from the group consisting of tributylamine, dicyclohexyl methyl amine, di-isopropyl ethyl amine, and mixtures thereof.
87 - 89 . (canceled)
90 . The method of claim 81 , wherein the solvent is polar.
91 - 92 . (canceled)
93 . The method of claim 81 , wherein the solvent further comprises an enhancer.
94 - 96 . (canceled)
97 . The method of claim 81 , wherein the step of recovering comprises separating at least a portion of the solvent phase from at least a portion of the aqueous phase, wherein both the separated solvent phase and the separated aqueous phase comprise acid/amine complex.
98 - 122 . (canceled)
123 . A method to recover an acid in the form of an ester from a solution of an organic acid salt, wherein the cation of the salt forms an insoluble carbonate salt, the method comprising:
a. introducing an amine, carbon dioxide and a solvent to the organic acid salt solution to form a mixture comprising an insoluble carbonate salt phase, an aqueous phase, a solvent phase and an acid/amine complex;
b. recovering the acid from the solvent phase;
c. reacting the acid with an alcohol to form an ester.
124 - 129 . (canceled)
130 . The method of claim 123 , wherein the amine is selected from the group consisting of tributylamine, dicyclohexyl methyl amine, di-isopropyl ethyl amine, and mixtures thereof.
131 - 133 . (canceled)
134 . The method of claim 123 , wherein the solvent is polar.
135 - 136 . (canceled)
137 . The method of claim 123 , wherein the solvent further comprises an enhancer.
138 - 140 . (canceled)
141 . The method of claim 123 , wherein the step of recovering comprises separating at least a portion of the solvent phase from at least a portion of the aqueous phase, wherein both the separated solvent phase and the separated aqueous phase comprise acid/amine complex.
142 . (canceled)
143 . The method of claim 141 , further comprising distilling the separated solvent phase to produce a distillate containing the acid and the alcohol, and a bottoms fraction comprising solvent and the amine obtained from the acid/amine complex.
144 . The method of claim 143 , further comprising reacting the acid with the alcohol in the distillate to form an ester.
145 - 166 . (canceled)
167 . A method for the recovery of organic acids from an aqueous salt solution, wherein the cation of the salt forms an insoluble carbonate salt, comprising:
a. introducing an amine, carbon dioxide and a solvent to the aqueous salt solution to form a mixture comprising an insoluble carbonate salt phase, an aqueous phase, a solvent phase, a first acid/amine complex comprising a first organic acid, and a second acid/amine complex comprising a second organic acid, wherein the first and second organic acids are not the same organic acid; and
b. recovering the organic acids from the solvent phase.
168 . The method of claim 167 , wherein the acids are recovered as a mixture of organic acids.
169 . The method of claim 167 , wherein the acids are recovered as compositions comprising individual organic acids.