Process for the production of carboxylic acids

Abstract

Aliphatic carboxylic acids of formulae (Ib) R 1 —COOH (Ia) and R 2 —COOH wherein R 1 is tertiary C 4-20 -alkyl and R 2 together are —(CH 2 ) n — with n=3 to 10, are produced by oxidizing an aliphatic or alicyclic ketone of the formula (II): wherein R 1 and R 2 are as defined above, with molecular oxygen in the presence of a soluble manganese (II) compound. The process has a high selectivity and is carried out under very mild conditions. It is especially useful for the production of dicarboxylic acids, such as, adipic acid, from cyclic ketones.

1 . A process for the production of aliphatic carboxylic acids of the general formulae  
         R 1 —COOH   (Ia)  
       and  
         R 2 —COOH   (Ib)  wherein R 1  is tertiary C 4-20 -alkyl    and R 2  is selected from hydrogen and C 1-6 -alkyl,    or R 1  and R 2  together are —(CH 2 ) n — with n=3 to 10,    comprising oxidizing a ketone of formula                          wherein R 1  and R 2  are as defined above,    with molecular oxygen in the presence of a soluble manganese(II) compound.    
     
     
         2 . The process of  claim 1 , wherein R 1  and R 2  together are —(CH 2 ) n — with n=3, 4, 5, 6 or 10.  
     
     
         3 . (canceled)  
     
     
         4 . The process of  claim 3 , wherein the soluble manganese (II) compound is manganese (II) nitrate.  
     
     
         5 . The process of  claim 4 , wherein the amount of manganese (II) nitrate is 0.1 to 4 mol % with respect to the amount of ketone (II).  
     
     
         6 . The process of  claim 5 , wherein at least one additive selected from the group consisting of nitric acid, soluble cobalt (II) compounds and soluble copper(II) compounds is used in an amount of 0.1 to 5 mol % with respect to the amount of ketone (II).  
     
     
         7 . The process of  claim 6 , wherein the oxidation is carried out in a solvent comprising at least one C 2-5 -alkanoic acid.  
     
     
         8 . The process of  claim 7 , wherein the molecular oxygen is used in essentially pure form or in a gaseous mixture containing up to 90 vol % of nitrogen and the total pressure is about 1 to 20 bar.  
     
     
         9 . The process of  claim 8 , wherein the reaction temperature is 0 to 100° C.  
     
     
         10 . The process of  claim 9 , wherein a solvent is present in an amount corresponding to a weight ratio solvent/ketone of 4 to 20.  
     
     
         11 . The process of  claim 1 , wherein the soluble manganese (II) compound is manganese (II) nitrate.  
     
     
         12 . The process of  claim 11 , wherein the amount of manganese (II) nitrate is 0.1 to 4 mol % with respect to the amount of ketone (II).  
     
     
         13 . The process of  claim 12 , wherein at least one additive selected from the group consisting of nitric acid, soluble cobalt (II) compounds and soluble copper (II) compounds, is used in an amount of 0.1 to 5 mol % with respect to the amount of ketone (II).  
     
     
         14 . The process of  claim 2 , wherein the soluble manganese (II) compound is manganese (II) nitrate.  
     
     
         15 . The process of  claim 14 , wherein the amount of manganese (II) nitrate is 0.1 to 4 mol % with respect to the amount of ketone (II).  
     
     
         16 . The process of  claim 15 , wherein at least one additive selected from the group consisting of nitric acid, soluble cobalt (II) compounds and soluble copper (II) compounds, is used in an amount of 0.1 to 5 mol % with respect to the amount of ketone (II).  
     
     
         17 . The process of  claim 1 , wherein the oxidation is carried out in a solvent comprising at least one C 2-5 -alkanoic acid.  
     
     
         18 . The process of  claim 1 , wherein the molecular oxidation is used in essentially pure form or in a gaseous mixture containing up to 90 vol % of nitrogen, and the total pressure is about 1 bar to 20 bar.  
     
     
         19 . The process of  claim 1 , wherein the reaction temperature is 0 to 100° C.  
     
     
         20 . The process of  claim 15 , wherein the reaction temperature is 20 to 70° C.  
     
     
         21 . The process of  claim 1 , wherein a solvent is present in an amount corresponding to a weight ratio solvent/ketone of 4 to 20.  
     
     
         22 . The process of  claim 9 , wherein the reaction temperature is 20 to 70° C.  
     
     
         23 . The process of  claim 1 , wherein the reaction temperature is 20 to 70° C.  
     
     
         24 . A process for the production of aliphatic carboxylic acids of formulae:  
         R 1 —COOH   (1a)  
       and  
         R 2 —COOH   (1b)  wherein R 1  and R 2  together are —(CH 2 ) n — and n is 3 to 10,    consisting of oxidizing a ketone of formula:                          wherein R 1  and R 2  are as defined above,    with molecular oxygen, in essentially pure form or in gaseous mixture with nitrogen, in the presence of a member selected from the group consisting of (a) a soluble manganese (II) salt, a soluble cobalt (II) salt and nitric acid, (b) a soluble manganese (II) salt and nitric acid, and (c) a soluble manganese (II) salt, a soluble copper (II) salt and nitric acid, and optionally in the presence of at least one solvent.