Method for separating formic acid from a reaction mixture
The invention relates to a method for separating formic acid from a reaction mixture which comprises, in addition to formic acid, a polyoxometalate ion of general formula [PMo x V y O 40 ] n− , where 6≤x≤11, 1≤y≤6, x+y=12 and 3<n<10, where n, x and y are each integers, wherein the separation occurs by means of an extraction using a linear primary alcohol, wherein the carbon chain of the alcohol comprises 5 to 12 carbon atoms, and the reaction mixture is present in a protic solvent.
1. A method for separating formic acid from a reaction mixture comprising in addition to formic acid a polyoxometalate ion of the general formula [PMo x V y O 40 ] n− , wherein 6≤x≤11, 1≤y≤6, x+y=12 and 3<n<10, wherein n, x and y are each integers, the separation being accomplished by extraction by means of a linear primary alcohol, wherein the carbon chain of the alcohol has five to twelve carbon atoms, and the reaction mixture is in a protic solvent.
2. The method according to claim 1 , wherein the linear primary alcohol has six, seven or eight carbon atoms.
3. The method according to claim 1 , wherein the linear primary alcohol comprises 1-hexanol or 1-heptanol.
4. The method according to claim 1 , wherein the protic solvent is an organic substance or the reaction mixture comprises an organic substance.
5. The method according to claim 4 , wherein the organic substance is an α-hydroxyaldehyde, an α-hydroxycarboxylic acid, a carbohydrate or a glycoside.
6. The method according to claim 1 , wherein the protic solvent is polar.
7. The method according to claim 1 , wherein the protic solvent is water.
8. The method according to claim 1 , wherein the linear primary alcohol is separated from at least a portion of the formic acid after extraction and added to the reaction mixture for further extraction of formic acid.
9. The method according to claim 1 , wherein n=3+y.
10. The method according to claim 1 , wherein the separation takes place by extraction during a reaction to produce formic acid.
11. The method according to claim 10 , wherein the separation takes place at a temperature of 50° C. to 120° C.