Synthesis of anhydroglycitol esters of improved colour

• US 6,693,209 B2
• Filed: 10/30/2002
• Issued: 02/17/2004
• Est. Priority Date: 05/04/2000
• Status: Expired due to Fees

• Current Assignee: Stichting Dienst Landbouwkundig Onderzoek
• Original Assignee: Ato B.V.
• Inventors: Luitjes, Hendrikus, Frissen, Augustinus Emmanuel, Van Es, Daniël Stephan
• Primary Examiner(s): Carr, Deborah
• Application Number:
  US10/258,968
• Publication Number:
  US 20030114635A1
• Time in Patent Office: 475 Days
• Field of Search: 554/229
• US Class Current: 554/229
• CPC Class Codes: C07D 493/04 Ortho-condensed systems

Abstract

Diesters of dianhydroglycitols can be prepared by esterification of dianhydroglycitols, anhydroglycitols and/or glycitols with alkylcarboxylic or arylcarboxylic acids in the presence of an acid catalyst, the acid catalyst being a macroporous acid ion exchange resin. If glycitols or monoanhydroglycitols are used as the starting material, the reaction temperature is initially of the order of 120° C. and after the dehydration is approximately 140° C.

Claims

1. A process for the preparation of esters of (di)anhydroglycitols by esterification of dianhydroglycitols, anhydroglycitols and/or glycitols with alkylcarboxylic or arylcarboxylic acids containing 3 to 18 carbon atoms in the presence of an acid catalyst, characterised in that the acid catalyst is a macroporous acid ion exchange resin, and the molar ratio of carboxylic acid to ((di)anhydro)glycitol is selected between 2 and 5.

2. A process according to claim 1, wherein the molar ratio of carboxylic acid to ((di)anhydro)glycitol is selected between 2 and 3.

3. A process according to claim 1, wherein the water of reaction is removed by passing a stream of inert gas through the reaction mixture.

4. A process according to claim 1, wherein the reaction temperature is between 120°

C. and 180°

C., in particular between 120°

C. and 150°

C.

5. A process according to claim 1, wherein a sulphonic acid ion exchange resin of the styrene-divinylbenzene copolymer type is used.

6. A process according to claim 5, wherein a macroporous ion exchange resin of the Amberlyst type is used.

7. A process according to claim 1, wherein the carboxylic acids contain 5 to 14 carbon atoms.

8. A process according to claim 1, wherein the dianhydroglycitol is isosorbide.

9. A process according to claim 1, wherein the anhydroglycitol is 1,4-sorbitan, 2,5-sorbitan or 3,6-sorbitan, or a mixture of sorbitan isomers.

10. A process according to claim 1, wherein sorbitol is esterified.

11. A process according to claim 1, wherein a glycitol or monoanhydroglycitol is esterified and the reaction temperature is kept between 120°

C. and 130°

C. during the dehydration reaction of the glycitol (first step) and the reaction temperature is raised to 130°

C. to 160°

C. after the dehydration reaction.

12. A process according to claim 1, wherein the reaction is carried out with active charcoal in the reaction mixture.