Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

Abstract

Various concentrations of cyclopropene fatty acids have been determined down to 0.2% by the use of gas liquid chromatographic (GLC) analysis of the methyl esters of fatty acids that have been quantitatively hydrogenated using a homogeneous transition metal complex catalyst. The effectiveness of the use of bromotris(triphenylphosphine)-rhodium(I), Br(P(C~ H s)3)3 Rh, as a homogeneous hydrogenation catalyst to convert the cyclopropene ring to a cyclopropane ring has been evaluated and compared with the analogous chloro-and iodo-complexes. The hydrogenation/GLC method of analysis has been compared with the method of titration with hydrogen bromide in benzene and with the method involving the use of high resolution nuclear magnetic resonance (NMR).

The refinement of renewable resources: New important derivatives of fatty acids and glycerol

“…Metal carbonyls, platinum-tin systems or iron, cobalt or nickel salts, which need activation by triethylaluminium, can be used as catalysts [17][18][19][20]. Moreover, modest results are only achieved using neutral precious metal-phosphine complexes such as the Wilkinson catalyst (RhCl(PPh 3 ) 3 ) or cationic complexes like [Rh(cod)(PPh 3 ) 2 ]BPh 4 [21]. A nearly quantitative selective hydrogenation of linoleic acid can be attained with a palladium nano-catalyst [22,23].…”

Analysis of triacylglycerols containing cyclopropane fatty acids in Sterculia fostida (Linn.) seed lipids

“…A number of methods have been reported (Conway et al, 1985) for the analysis of fatty acid methyl esters containing CPFA moieties. These include the use of a well-conditioned glass column packed with nonpolar stationary phase at low temperature (150 °C) (Fisher and Schuller, 1981;Bianchini et al, 1981) and hydrogenation of cyclopropene moieties to cyclopropane moieties using heterogeneous (Cornelius et al, 1965;Hammonds and Shone, 1966) and homogeneous (Bland et al, 1984) catalysts followed by GLC analysis. These methods could not be used for the successful analysis of triacylglycerols into their molecular species possessing CPFA moieties. Keeping in view the above difficulties, we believed the best way to analyze the CPFA-containing triacylglycerols would be to modify the cyclopropene group to an oxygenated derivative under very mild conditions so that they can be easily separated and analyzed by conventional chromatographic techniques.…”

A Capillary GC Determination of Cyclopropenoid Fatty Acids in Cottonseed Oils

“…However, GC of CPEFA methyl esters has not been successful; unlike other fatty acid methyl esters (FAMES), CPEFA methyl esters were reported to be thermally decomposed on the conventional polar columns (Recourt et al, 1967). In order to make CPEFAs heat stable for GC analysis, a second derivatization altering the cyclopropene moiety was sought through either hydrogenation (Cornelius et al, 1965;Bland et al, 1984;Conway et al, 1985) or reaction with methyl mercaptan (Raju and Reiser, 1966) or methanolic silver nitrate (Kircher, 1965; Authors Park and Rhee are with the Food Protein R & D Center, Faculty Mail Box 183, Texas A&M Univ., College Station, TX 77843-2476. Schneider et al, 1968).…”