Thermal salt-splitting of (alkyl)ammonium 3-hydroxypropionate

摘要

A salt-splitting liquid (SSL) and a process that uses the SSL to “split” (alkyl)ammonium 3-hydroxypropionate salts into ammonia (or amines) and 3-hydroxypropionic acid (3-HP) that minimizes increases in viscosity and condensation reactions of the 3-HP. Converting (alkyl)ammonium 3-hydroxypropionate in an aqueous mixture to 3-HP includes admixing a polar aprotic organic solvent and an azeotroping solvent with the aqueous mixture. The azeotroping solvent forms an azeotrope mixture with water of the aqueous mixture. The SSL is heated to convert the (alkyl)ammonium 3-hydroxypropionate to 3-HP and ammonia, where heating produces a vapor phase containing at least water, ammonia and the azeotroping solvent. At least a portion of the water and the ammonia is removed from the vapor phase during the heating, and at least a portion of the azeotroping solvent is returned from the vapor phase back to SSL to maintain the azeotrope mixture with the water.

主权项

1. A process of converting an (alkyl)ammonium 3-hydroxypropionate in an aqueous mixture to 3-hydroxypropionic acid (3-HP), the process comprising:
admixing a polar aprotic organic solvent and the aqueous mixture, where the (alkyl)ammonium 3-hydroxypropionate and the 3-HP are soluble in the polar aprotic organic solvent; admixing an azeotroping solvent and the aqueous mixture and the polar aprotic organic solvent, where the azeotroping solvent forms an azeotropic mixture with water of the aqueous mixture and the aqueous mixture, the polar aprotic organic solvent and the azeotroping solvent form a salt-splitting liquid; heating the salt-splitting liquid to convert the (alkyl)ammonium 3-hydroxypropionate to 3-HP and ammonia, where heating the salt-splitting liquid produces a vapor phase containing at least water, ammonia and the azeotroping solvent; removing at least a portion of the water and the ammonia from the vapor phase during the heating; and returning at least a portion of the azeotroping solvent from the vapor phase back to the salt-splitting liquid to maintain the azeotrope mixture with the water of the aqueous mixture.