Microbial process for the preparation of acetic acid, as well as solvent for its extraction from the fermentation broth

An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

• (a) fermenting in a bioreactor at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide, and hydrogen, and (4) carbon monoxide and hydrogen, in the presence of an aqueous stream comprising a nutrient mixture with an anaerobic acetogenic bacteria, thereby producing a fermentation broth comprising acetic acid:
• (b) contacting said fermentation broth with a solvent for a time sufficient to cause the formation of a solvent phase containing acetic acid, said solvent and water and an aqueous phase, wherein said solvent comprises:
• (i) a water immiscible solvent comprising greater than 50% by volume of a mixture of isomers of highly branched di-alkyl amines, and from about 0.01% to 20% by volume of mono-alkyl amines, said solvent having a coefficient of distribution greater than 10;
• and
• (ii) at least 10% by volume of a non-alcohol co-solvent having a boiling point lower than the boiling point of said solvent (i),
• wherein said mixture extracts acetic acid from aqueous streams;
• (c) continuously distilling acetic acid from said solvent phase;
• and
• (d) recycling said solvent to said contacting step (b).

An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

• (a) fermenting in a bioreactor at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide, and hydrogen, and (4) carbon monoxide and hydrogen in the presence of an aqueous stream comprising a nutrient mixture with an anaerobic acetogenic bacteria, thereby producing a fermentation broth comprising acetic acid and dissolved carbon dioxide;
• (b) removing said carbon dioxide from said fermentation broth;
• (c) contacting said broth of (b) with a solvent comprising an amine for a time sufficient to cause the formation of a solvent phase containing acetic acid, said solvent and water and an aqueous phase;
• (d) continuously distilling acetic acid from said solvent phase;
• and
• (e) recycling said solvent to said contacting step (c).

An anaerobic microbial fermentation process for the production of acetic acid, said process comprising the steps of:

• (a) fermenting in a bioreactor at least one gas selected from the group consisting of (1) carbon monoxide, (2) carbon dioxide and hydrogen, (3) carbon monoxide, carbon dioxide, and hydrogen, and (4) carbon monoxide and hydrogen, in the presence of an aqueous stream comprising a nutrient mixture with an anaerobic acetogenic bacteria, thereby producing a fermentation broth comprising acetic acid;
• (b) contacting said broth of (a) with a solvent for a time sufficient to cause the formation of a solvent phase containing acetic acid, said solvent and water and an aqueous phase, wherein said solvent comprises:
• (i) a water immiscible solvent comprising greater than 50% by volume of a mixture of isomers of highly branched di-alkyl amines, and from about 0.01% to 20% by volume of mono-alkyl amines, said solvent having a coefficient of distribution greater than 10;
• and
• (ii) at least 10% by volume of a linear hydrocarbon co-solvent having a boiling point lower than the boiling point of said solvent (i),
• wherein said mixture extracts acetic acid from aqueous streams;
• (c) continuously distilling acetic acid from said solvent phase;
• and
• (d) recycling said solvent to said contacting step (b).