US EPA

5337112 

Journal Article 

TRANSITION-METAL CATALYZED OXIDATION OF UNSATURATED FATTY-ACIDS - SYNTHESIS OF KETOCARBOXYLIC ACIDS AND DICARBOXYLIC-ACIDS 

Warwel, S; Pompetzki, W; Deckwirth, EA 

1991 

93 

6 

210-215 

10.1002/lipi.19910930603 

WOS:A1991FW68400003 

Terminal unsaturated C-10-C-14-fatty acid methylesters (9-decenoic-, 10-undecenoic-, 13-tetradecenoic methylesters) were converted to methylketocarboxylic methylesters (yields: 60-75%, isolated) by oxidation with O2/H2O at roomtemperature under catalysis of PdCl2/CuCl2. Using RhCl3/FeCl3 at 80-degrees-C yields of 40-60% were obtained. For the first time methyl oleate was converted directly to a mixture of 9-oxo- and 10-oxo-stearic acid methylester by palladium catalyzed oxidation. In DMF/H2O the selectivity to these two ketoesters was 85% (15% isomers), in dioxane/H2O the selectivity droped to 55% while the yield of the oxostearic acid esters climbed to 70%. The Mn-catalyzed oxidative cleavage of methylketocarboxylic acid esters with O2 at 115-degrees-C led in each case to a mixture of two dicarboxylic acid esters in a molar ratio of 2:1. Starting with 9-oxodecanoic acid azelaic acid and suberic acid were obtained at a conversion rate of 90%. Analogous 10-oxoundecanoic acid led to C-10/C-9- and 13-oxotetradecanoic acid led to C-13/C-12-dicarboxylic acids. The oxidative cleavage of 9-/10-oxostearic acid methylester yielded mixtures of C-8-C-10-monocarboxylic acids and methylesters of C-8-C-10-dicarboxylic acids.