Azeotropic distillation of cyclic esters of hydroxy organic acids
OwnerMichael Charles Milner Cockrem, Istvan Kovacsinventors
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Abstract
Cyclic esters of hydroxy organic acids can be produced and recovered via azeotropic distillation. In certain embodiments cyclic esters, such as glycolide and lactide, can be produced from a fermentation broth or other feed stream that comprises a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid using azeotropic distillation. The hydroxy organic acid of the feed stream or the hydroxy organic acid derived from the feed stream by decomposition is reacted to produce the cyclic ester. In other embodiments a crude composition of a cyclic ester of an organic ester can be purified using azeotropic distillation.
Claims54
An azeotropic distillation process for the recovery of at least one cyclic ester of a hydroxy organic acid from a feed stream comprising at least one of a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid comprising the steps of:
- mixing a feed stream and at least one azeotroping agent, wherein the feed stream comprises at least one of a hydroxy organic acid, an ammonium salt of a hydroxy organic acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid and wherein the azeotroping agent is capable of forming at least one azeotrope comprising a cyclic ester of a hydroxy organic acid;
- heating at least one of the feed stream, the azeotroping agent, or the mixture comprising them, thereby producing a first vapor stream comprising at least one azeotrope comprising the cyclic ester of the hydroxy organic acid and the azeotroping agent;
- and
- separating the first vapor stream from the mixture.
The process of claim 1, wherein the cyclic ester is produced by a reaction that also produces a dimer or an oligomer of the hydroxy organic acid as a leaving group.
A process for recovering a cyclic ester of a hydroxy organic acid from a crude composition of a cyclic ester, comprising the steps of:
- mixing a crude composition of a cyclic ester of a hydroxy organic acid with an azeotroping agent that is capable of forming an azeotrope with the cyclic ester;
- heating the mixture to produce a vapor stream that comprises an azeotrope comprising the cyclic ester and the azeotroping agent;
- and
- condensing the vapor stream.
A process for the production of at least one cyclic ester of a hydroxy organic acid from a feed stream comprising at least one of a hydroxy organic acid, an ammonium salt of a hydroxy acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid, comprising the steps of:
- mixing a feed stream and at least one azeotroping agent, wherein the feed stream comprises at least one of a hydroxy organic acid, an ammonium salt of a hydroxy acid, an amide of a hydroxy organic acid, or an ester of a hydroxy organic acid, and wherein the azeotroping agent is capable of forming at least two azeotropes, a first azeotrope comprising a hydroxy organic acid, and a second azeotrope comprising a cyclic ester of a hydroxy organic acid;
- heating the mixture comprising the feed stream and the at least one azeotroping agent in a first column to produce a first vapor stream that comprises a first azeotrope comprising the hydroxy organic acid and the azeotroping agent;
- feeding the first vapor stream to a second column;
- and
- reacting the hydroxy organic acid of the first vapor stream in the second column to produce at least one cyclic ester of the hydroxy acid and water, wherein a second overhead vapor stream from the second column comprises water and azeotroping agent, and a bottoms stream from the second column comprises at least one cyclic ester of the hydroxy acid.
A process for the separation of a hydroxy organic acid from a cyclic ester thereof comprising the steps of:
- mixing a feed stream comprising a hydroxy organic acid and a cyclic ester thereof and at least one azeotroping agent that is capable of forming at least two azeotropes, a first azeotrope comprising the hydroxy organic acid and a second azeotrope comprising a cyclic ester of the hydroxy organic acid;
- heating at least one of the feed stream, the azeotroping agent, or the mixture thereof to produce a first vapor stream that comprises the first azeotrope comprising hydroxy organic acid and azeotroping agent;
- and
- separating the first vapor stream from the mixture, producing a bottoms stream comprising cyclic ester of the hydroxy organic acid and azeotroping agent.
A process for the separation of L-lactide from meso-lactide comprising the steps of:
- mixing a feed stream comprising L-lactide and meso-lactide and at least one azeotroping agent that is capable of forming at least two azeotropes, a first azeotrope comprising L-lactide, and a second azeotrope comprising meso-lactide;
- heating at least one of the feed stream, the azeotroping agent, or the mixture thereof to produce a first vapor stream that comprises a first azeotrope comprising L-lactide and azeotroping agent;
- and
- separating the first vapor stream from the mixture, producing a bottoms stream comprising meso-lactide and azeotroping agent.
Dependencies are inferred from the claim text.