Methods for producing alkyl hydroxyalkanoates

Patent metadata

Field	Value
Publication number	US-9944586-B2
Application number	US-201415029376-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Oct 17, 2013
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Methods and systems for producing alkyl hydroxyalkanoate from hydroxy carboxylic acid recovery bottoms. The methods generally comprise the steps of obtaining a hydroxy carboxylic acid recovery bottom, adding a mono-alcohol to the hydroxy carboxylic acid recovery bottom to obtain a first mixture, heating the first mixture in the presence of a catalyst to form a reaction product, distilling the reaction product, and recovering an alkyl hydroxyalkanoate fraction.

First claim

The invention claimed is:

1. A method for producing ethyl lactate, comprising:
a) obtaining a hydroxyalkanoate containing composition, comprising:
(i) at least 40 percent by weight hydroxyalkanoate equivalents;
(ii) greater than 0 and less than 45 percent by weight free hydroxyalkanoates;
(iii) at least 1 percent by weight saccharide equivalents; and
(iv) less than 15 percent by weight water;

b) mixing ethanol in a molar ratio of from about 1.1 to 1.0 to about 10.0 to 1.0 of ethanol to hydroxyalkanoate equivalents present in the hydroxyalkanoate containing composition to obtain a first mixture;
c) heating the first mixture to form a reaction product;
d) distilling the reaction product and recovering an ethyl lactate fraction comprising:
(i) at least 90 percent by weight ethyl lactate;
(ii) less than 1 percent by weight lactic acid;
(iii) less than 1 percent by weight water; and
(iv) less than 0.5 percent by weight saccharide equivalents.

2. The method of claim 1 , wherein step (d) further comprises separating the reaction product into a first fraction enriched in the ethanol and water, and a second fraction enriched in the ethyl lactate, wherein the ethyl lactate fraction is recovered from the second fraction.

3. The method of claim 1 , wherein step (d) comprises:
a first step to provide a first fraction enriched in water and ethanol and a second fraction enriched in the ethyl lactate and the saccharide equivalents; and
a second step to fractionate the second fraction into a saccharide equivalents enriched fraction, and the ethyl lactate fraction.

4. The method of claim 1 , wherein step (d) comprises:
a first step to provide a first fraction enriched in water, ethanol, and ethyl lactate and a second fraction enriched in saccharide equivalents; and
a second step to fractionate the first fraction into a water and ethanol enriched fraction and the ethyl lactate fraction.

5. The method of claim 1 , wherein the first mixture is heated to a temperature of from about 50° C. to about 300° C.

6. The method of claim 1 , wherein the pressure in step (c) ranges from 1 atm to 100 atm.

7. The method of claim 1 , wherein the hydroxyalkanoate containing composition comprises at least 50 percent by weight of hydroxyalkanoate equivalents.

8. The method of claim 1 , wherein the hydroxyalkanoate containing composition comprises between 0.5 and 40 percent free hydroxyalkanoates.

9. The method of claim 1 , wherein the hydroxyalkanoate containing composition comprises at least 2 percent by weight saccharide equivalents.

10. The method of claim 1 , wherein the hydroxyalkanoate containing composition comprises less than 15 percent by weight water.

11. The method of claim 1 , wherein a pressure below atmospheric pressure is utilized during step (d) to recover the ethyl lactate fraction.

12. The method of claim 1 , wherein the percent yield of ethyl lactate from hydroxyalkanoate equivalents is greater than 50%.

13. The method of claim 1 , wherein the percent yield of ethyl lactate from the hydroxyalkanoate equivalents is greater than 90%.

14. The method of claim 1 , wherein percent recovery of ethyl lactate from hydroxyalkanoate equivalents is greater than 50%.

15. The method of claim 1 , wherein the ethyl lactate fraction comprises less than 0.1 by weight saccharide equivalents.

Assignees

• Cargill Inc

Inventors

• Abraham Timothy Walter
• Duran Anthony Louis
• Edgar Stephen C
• Gokarn Ravi R

Classifications

• C07C67/54

  by distillation · CPC title

• C07C67/08 Primary

  by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds · CPC title

• C07C67/03 Primary

  by reacting an ester group with a hydroxy group · CPC title

• C07C69/68

  Lactic acid esters · CPC title