Vinyl acid monomer recovery

1. A method for recovering itaconic acid monomer by:

(a) providing an aqueous fermentation broth which undergoes microbial fermentation of a nutrient medium containing a carbon source including at least one microorganism to produce itaconic acid;

(b) extracting the itaconic acid from said aqueous fermentation broth into an organic phase by exposure to a hydrophobic Lewis base having a solubility in water of less than or equal to 1.0 g/L, wherein the itaconic acid monomer is present in a salt form in said organic phase;

(c) exposing said itaconic acid salt in said organic phase to an aqueous phase containing a base and recovering said itaconic acid salt in an aqueous phase as a partially neutralized salt of said itaconic acid monomer.

2. The method of claim 1 wherein said hydrophobic Lewis base comprises a tertiary amine (R 3 N) wherein the R groups are selected from one of an alkyl group, substituted alkyl group, aromatic group, or substituted aromatic group.

3. The method of claim 1 wherein said hydrophobic Lewis base comprises a phosphate having the formula (RO) 3 PO wherein the R groups are selected from one of an alkyl group, substituted alkyl group, aromatic group, or substituted aromatic group.

4. The method of claim 1 wherein the extraction is carried out in the additional presence of a polar organic compound that has a solubility in water of less than or equal to 0.1 g/L.

5. The method of claim 1 including the additional step of exposing said partially neutralized salt of said vinyl acid monomer to acid and reducing the pH to at or below 3.1 and converting said partially neutralized salt of said vinyl acid monomer to vinyl acid monomer.

6. The method of claim 4 wherein the additional polar organic compound comprises an organic alcohol having eight or more carbon atoms.

7. The method of claim 1 wherein said extraction is carried out in the additional presence of an organic diluents which reduces the viscosity of the extraction media and which diluent has a water solubility of less than or equal to 0.1 g/L.

8. The method of claim 1 wherein said Lewis base is present at a level of 1.0 to 40.0 vol. %.

9. The method of claim 1 wherein extraction is carried out at a temperature of 15.0° C. to 90° C.

10. The method of claim 1 wherein in step (c), said base comprises M + [OH] − wherein M is selected from K, Na, NH 4.

11. The method of claim 1 wherein in step (c) said base comprises M + ([OH] − ) 2 where M is selected from Ca or Ba.

12. The method of claim 1 wherein said partially neutralized salt of said vinyl acid monomer recovered in step (c) has a partial neutralization of 25.0 mole % to 85.0 mole %.

13. The method of claim 1 wherein 50.0% or more of said vinyl acid monomer from said aqueous fermentation broth is converted into said salt form of said vinyl acid monomer in said organic phase.

14. The method of claim 1 wherein 50.0% or more of said vinyl acid monomer in said organic phase is converted to said partially neutralized salt of said vinyl acid monomer in said aqueous phase.

15. The method of claim 1 wherein said itaconic acid producing microorganism comprises a microorganism of the genus Aspergillus.

16. The method of claim 15 wherein said microorganism comprises Aspergillus terreus, Asperfillus itaconicus or Aspergillus niger.

17. The method of claim 1 wherein said itaconic acid producing microorganism comprises Utsilago aeae, Helicobasidium mompa, Candia or Pseudozyma antartica.

18. The method of claim 1 wherein said nutrient medium containing a carbon source comprises a mono- or disaccharides, corn oil, ethanol, glycerol, inulin, D-mannose, cellobiose, or D-xylose.

19. The method of claim 1 wherein said nutrient medium comprises an inorganic salt of Ca, Mg, Na, K, Fe, Ni, Co, Cu, Mn, or Zn.

20. The method of claim 1 wherein said nutrient medium comprises a source of nitrogen comprising an amino acid, urea, or ammonium nitrate.