Control of color-body formation in isohexide esterification

Patent metadata

Field	Value
Publication number	US-9828387-B2
Application number	US-201415102281-A
Country	US
Kind code	B2
Filing date	Nov 19, 2014
Priority date	Dec 18, 2013
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A method for preparing esters from isohexide compounds, and a means by which color bodies that may be made in situ during esterification of isohexide compounds are either prevented from forming or their amounts are minimized in the resultant product mixture are described.

First claim

We claim:

1. A method for preparing an isohexide ester, comprising: reacting an isohexide and an organic acid, in the presence of a phosphonic acid (H 3 PO 3 ) catalyst at a temperature from 150 degrees Celsius up to 250 degrees Celsius for a time sufficient to produce the isohexide ester while limiting formation of color bodies in a product mixture to an APHA value of less than 230.

2. The method according to claim 1 , further comprising reducing color bodies or color-generating precursor compounds in a preparation of said isohexide or organic acid prior to esterification.

3. The method according to claim 2 , wherein reducing color bodies or precursor compounds involves purifying the organic acid by at least one of chromatography, crystallization, or distillation.

4. The method according to claim 1 , wherein said product mixture exhibits an APHA value of ≦185.

5. The method according to claim 1 , wherein said product mixture exhibits an APHA value of ≦150.

6. The method according to claim 1 , wherein said isohexide is transformed to said isohexide ester at a conversion rate of at least 40%.

7. The method according to claim 6 , wherein said conversion rate is about 50% or greater.

8. The method according to claim 6 , wherein said conversion rate is about 70% or greater.

9. The method according claim 1 , wherein said isohexide is at least one of: isosorbide, isomannide, and isoiodide.

10. The method according to claim 1 , wherein said organic acid is at least one of an alkanoic acid, alkenoic acid, or aromatic acid, having C 2 -C 26 .

11. The method according to claim 10 , wherein said acid is 2-ethylhexanoic acid.

12. The method according to claim 1 , wherein said phosphonic acid catalyst is present in an amount >5.0 wt. % of a reaction mixture of said isohexide and organic acid.

13. The method according to claim 1 , wherein said phosphonic acid catalyst is present in an amount from about 2.5 wt. % to about 5.0 wt. % of a reaction mixture of said isohexide and organic acid.

14. The method according to claim 1 , wherein said phosphonic acid catalyst is present in an amount <2.5 wt. % of a reaction mixture of said isohexide and organic acid.

15. The method according to claim 12 , wherein said product mixture contains predominantly diesters.

16. The method according to claim 13 , wherein said product mixture contains about a 1:1 ratio of monoesters and diesters.

17. The method according to claim 14 , wherein said product mixture contains predominantly monoesters.

18. An ester product mixture comprising an isohexide ester prepared from an isohexide and an organic acid, in the presence of a reducing Brønsted acid catalyst, wherein said ester product mixture exhibits an APHA value of less than 230, and may contain said reducing Brønsted acid.

19. The ester product mixture formed according to claim 18 , wherein said APHA value is ≦180.

20. The ester product mixture formed according to claim 18 , wherein said reducing Brønsted acid catalyst is phosphonic acid (H 3 PO 3 ).

21. A method of making a polyester comprising, obtaining an isohexide ester monomer according to claim 1 or in the ester product mixture of claim 18 , and polymerizing said isohexide ester monomer either alone with itself or with at least an additional other monomer.

Assignees

• Archer Daniels Midland Co

Inventors

• Stensrud Kenneth
• Hagberg Erik
• Rockafellow Erin

Classifications

• B01J31/0257

  Phosphorus acids or phosphorus acid esters · CPC title

• C07D493/04 Primary

  Ortho-condensed systems · CPC title