Process for preparing mandelic aromatic compounds and aromatic aldehyde compounds

Patent metadata

Field	Value
Publication number	US-10544081-B2
Application number	US-201415036871-A
Country	US
Kind code	B2
Filing date	Nov 14, 2014
Priority date	Nov 15, 2013
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

A process for preparing an aromatic compound or compounds where at least one mandelic group —CHOH—COOH is described, comprising a reaction for condensation of at least one aromatic compound with glyoxylic acid or derivatives thereof, wherein said condensation reaction is carried out substantially in the absence of any acid or any base added to the reaction medium. The condensation reaction is followed by an oxidation reaction in order to obtain aromatic aldehyde.

First claim

The invention claimed is:

1. A process for the preparation of one or more mandelic aromatic compounds carrying at least one mandelic —CHOH—COOH group comprising:
reacting at least one aromatic compound with glyoxylic acid or esters of glyoxylic acid under condensation conditions in the absence of any added acid or added base other than those constituted by reactants, an optional catalyst and an optional solvent, wherein the said aromatic compound is a substituted benzene substituted by one or more alkoxy groups, phenol or a substituted phenol according to formula (I):

wherein:
R represents one or more identical or different substituents,
x, the number of substituents on a ring, is an integer between 1 and 4,

wherein R is selected from the group consisting of hydroxyl, linear or branched alkyl having from 1 to 6 carbon atoms, linear or branched alkoxy having from 1 to 6 carbon atoms and wherein a molar ratio of the said aromatic compound to glyoxylic acid or esters of glyoxylic acid varies from 0.9 to 1.1; and
recovering condensation products directly after the condensation reaction of the at least one aromatic compound with glyoxylic acid or esters of glyoxylic acid without intervening steps.

2. The process of claim 1 , wherein said aromatic compound is a substituted phenol wherein the position para with respect to the hydroxyl group of the substituted phenol according to formula (I) is unsubstituted.

3. The process of claim 1 , wherein the substituted phenols are selected from the group consisting of o-cresol, m-cresol, 3-ethylphenol, 2-(tert-butyl)phenol, guaiacol, and guaethol.

4. The process of claim 1 , wherein the glyoxylic acid is in the monohydrate form.

5. The process of claim 1 , wherein the step of reacting is carried out in the presence of at least one catalyst.

6. The process of claim 5 , wherein the catalyst is selected from transition metal complexes comprising oxygen-comprising ligands.

7. The process of claim 5 , wherein the catalyst is selected from the group consisting of: iron(II) acetate, iron(III) acetate, copper(II) acetate, iron(II) acetylacetonate, iron(III) acetylacetonate, copper(II) acetylacetonate, and copper(III) acetylacetonate.

8. The process of claim 5 , wherein the catalyst comprises a complex composed of a transition metal and at least one glyoxylate ligand.

9. The process of claim 1 , wherein the optional solvent is selected from the group consisting of water, aromatic hydrocarbons, alcohols, and water-alcohol mixtures.

10. The process of claim 1 , wherein the process consists of reacting the glyoxylic acid with guaiacol, with guaethol, or with guaiacol and guaethol.

11. A process for the preparation of one or more mandelic aromatic aldehydes comprising:
reacting at least one aromatic compound with glyoxylic acid or esters of glyoxylic acid according to the process of claim 1 to prepare one or more mandelic aromatic compounds, and
oxidizing the one or more mandelic aromatic compounds.

12. The process of claim 11 , wherein the step of oxidizing is carried out without addition of alkaline agent.

13. The process of claim 11 , wherein the step of oxidizing is carried out in the presence of water as solvent.

14. The process of claim 11 , wherein the step of oxidizing is carried out in the presence of a catalyst selected from the group consisting of chromium, cobalt, copper, vanadium, manganese, iron, nickel and osmium derivatives.

15. The process of claim 11 , wherein the one or more aromatic aldehydes comprise vanillin, ethylvanillin, or vanillin and ethylvanillin.

16. The process of claim 1 , wherein recovering the condensation products involves separation of mandelic aromatic compounds obtained from the condensation reaction by crystallization.

17. The process of claim 1 , wherein recovering the condensation products involves separation of mandelic aromatic compounds obtained from the condensation reaction by extraction with at least an organic solvent.

18. The process of claim 1 , wherein the reactor contents consist essentially of the reactants, the optional catalyst, the optional solvent, and an optional inert atmosphere.

Assignees

• Rhodia Operations

Inventors

• Garel Laurent
• Sarrazin Flavie
• Back Olivier
• Olivon Kevin
• Pucheault Mathieu

Classifications

• C07C51/367 Primary

  by introduction of functional groups containing oxygen only in singly bound form · CPC title

• C07C47/58

  Vanillin · CPC title

• C07C47/575

  containing ether groups, [IMAGE cpc-sch-C07C-0958.gif] groups,[IMAGE cpc-sch-C07C-0959.gif] groups, or[IMAGE cpc-sch-C07C-0960.gif] groups · CPC title

• C07C45/39

  being a secondary hydroxyl group · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title