Carbonate-promoted carboxylation reactions for the synthesis of valuable organic compounds

1. A method for synthesizing a dicarboxylate compound containing an aromatic heterocycle, comprising:

providing a carboxylic acid containing an aromatic heterocycle;

providing a CO 3 2− salt with Cs + cations to form a mixture, which converts the carboxylic acid containing an aromatic heterocycle to a carboxylate containing an aromatic heterocycle;

providing a CO 2 gas to the mixture; and

heating the mixture to a temperature to at least partially melt the carboxylate containing an aromatic heterocycle.

2. The method as recited in claim 1 , where the dicarboxylate compound is thiophene-2, 5-dicarboxylate, and wherein the carboxylic acid containing an aromatic heterocycle is thiophene-2-carboxylic acid, and wherein the carboxylate containing an aromatic heterocycle is thiophene-2-carboxylate.

3. The method as recited in claim 1 , where the carboxylic acid containing an aromatic heterocycle and more than one-half equivalent of CO 3 2− salt are combined to form the mixture of carboxylic acid containing an aromatic heterocycle salt and CO 3 2− salt prior to heating under CO 2 .

4. The method as recited in claim 1 , wherein the mixture has K + cations.

5. The method as recited in claim 1 , wherein the mixture only has K + cations and further comprising providing an additional carboxylate salt with K + cations, to aid melting at a lower temperature.

6. The method as recited in claim 1 , where the temperature is between 100° C. and 450° C.

7. The method as recited in claim 1 , where the temperature is between 200° C. and 350° C.

8. The method as recited in claim 1 , where the temperature is between 200° C. and 300° C.

9. The method, as recited in claim 1 , further comprising isolating and recovering the Cs + anions.

10. The method, as recited in claim 9 , wherein the isolating and recovering the Cs + anions, comprises:

generating a CsCl aqueous solution;

using a bipolar membrane electrodialysis to covert CsCl into HCl and CsOH solutions; and

combining the CsOH solution with CO 2 gas to form Cs 2 CO 3 .