Method of extracting carbonic acid, aliphatic acids, esters and alcohols from an aqueous medium

1 . A method of extracting at least one compound selected from the group consisting of: carbonic acid, an aliphatic acid, an aliphatic acid ester, and an aliphatic alcohol from an aqueous medium, the method comprising the steps:

(a) contacting the carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol in the aqueous medium comprising living microorganisms with an extracting medium comprising at least one alkyl-phosphine oxide and a second organic component with at least 12 carbons wherein said second organic component is a linear or branched alkane, an aromatic hydrocarbon, or an alcohol, for a time sufficient to extract the carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol from the aqueous medium into the extracting medium; and

(b) separating the extracting medium with the extracted carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol from the aqueous medium;

wherein:

the at least one alkyl-phosphine oxide comprises at least two different straight or branched alkyl radicals per alkyl-phosphine oxide molecule;

the aqueous medium in step (a) comprises a living microorganism producing the carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol, and the living microorganism is contacted by the extracting medium during extraction;

the at least one alkyl-phosphine oxide accounts for at least 50 wt.-% of the total extracting medium and the amount of carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol formed in the presence of the alkyl-phosphine oxide is not reduced compared to when said alkyl-phosphine oxide is absent;

the pH of the aqueous medium during step (a) is from 5.0 to 9.0; and

the microorganism is cultured at a temperature ranging from about 20° C. to about 80° C.

2 . The method of claim 1 , wherein:

the aliphatic acid is a monofunctional aliphatic acid;

in the aliphatic acid ester, the aliphatic acid radical is a monofunctional aliphatic acid radical; and

the aliphatic alcohol is a monohydric alcohol.

3 . The method of claim 2 , wherein alkanoic chains in the aliphatic acid, the aliphatic acid ester, and the aliphatic alcohol are unbranched.

4 . The method of claim 1 , wherein the aliphatic acid, aliphatic acid ester and/or aliphatic alcohol comprises 4 to 18 carbon atoms.

5 . The method of claim 4 , wherein the aliphatic acid, aliphatic acid ester and/or aliphatic alcohol comprises 6 to 8 carbon atoms.

6 . The method of claim 4 , wherein the aliphatic acid, aliphatic acid ester and/or aliphatic alcohol is selected from the group consisting of: butanol, pentanol, hexanol, butanoic acid, pentanoic acid, hexanoic acid, and the methyl- and ethyl-esters of butanoic acid, pentanoic acid, and hexanoic acid.

7 . The method of claim 1 , wherein the alkyl-phosphine oxide is an alkyl-phosphine oxide of general formula 1:

wherein R 1 , R 2 and R 3 are straight or branched alkyl radicals comprising 4 to 18 carbon atoms; with the proviso, that at least two of R 1 , R 2 and R 3 differ from each other.

8 . The method of claim 7 , wherein R 1 , R 2 and R 3 are straight or branched alkyl radicals comprising 6 to 12 carbon atoms.

9 . The method of claim 7 , wherein R 1 , R 2 and R 3 are straight or branched alkyl radicals comprising 8 to 10 carbon atoms.

10 . The method of claim 9 , wherein, relative to all alkyl-phosphine oxides of general formula 1 in the extracting medium, the molar ratio of all alkyl radicals of the alkyl-phosphine oxides comprising 8 and 10 carbon atoms is in the range of from 1.0:2.0 to 2.0:1.0.

11 . The method of claim 10 , wherein the molar ratio of all alkyl radicals of the alkyl-phosphine oxides comprising 8 and 10 carbon atoms is in the range of from 1.0:1.2 to 1.2:1.0.

12 . The method of claim 1 , wherein the at least one alkyl-phosphine oxide accounts for at least 80 wt.-% of the total extracting medium.

13 . The method of claim 1 , wherein the at least one alkyl-phosphine oxide accounts for at least 90 wt.-% of the total extracting medium.

14 . The method of claim 1 , wherein the extracting medium further comprises at least one alkane comprising at least 12 carbon atoms.

15 . The method of claim 1 , wherein the extracting medium further comprises at least one alkane comprising 12 to 18 carbon atoms.

16 . The method of claim 15 , wherein the weight ratio of alkyl-phosphine oxide to alkane in the extracting medium is between 1:2 and 50:1.

17 . The method of claim 1 , wherein the extracting medium comprises an aromatic solvent.

18 . The method of claim 15 , wherein the second organic component with at least 12 carbons is selected from the group consisting of: tetradecane, pentadecane, hexadecane, heptadecane, octadecane, diisopropylbiphenyl, partly hydrogenated terphenyl, dibenzyltoluol, diisopropylnaphthalene, oleyl alcohol, 2-octyldodecanol, 2-hexyldodecanol and combinations thereof.

19 . The method of claim 1 , wherein the extracting medium is present when the carbonic acid, aliphatic acid, aliphatic acid ester or aliphatic alcohol is biotechnologically produced.