Octadecadiensäuren im Butterfett II. Mitteilung: Identifizierung einiger nichtkonjugierbarer Fettsäuren

Octadecadienoic Acids in Butterfat II: Identification of a Few Nonconjugable Fatty Acids With the help of gas and thin-layer chromatography as well as by determining the position of double bonds with OsO₄, the following iso-linoleic acids in the butter fat were identified: cis,trans (or trans,cis): 11, 16 and/or 11, 15; 10, 16 and/or 10, 15; 9, 15 and/or 9, 16; 8, 16 and/or 8, 15 and/or 8, 12. trans,trans: 12, 16; 11, 16 and/or 11, 15; 10, 16 and/or 10, 15; 9, 16 and/or 9, 15 and/or 9, 13.     

Alkylendiamide und Alkylendiisoimide von Äthyleniminocarbonsäuren und -dicarbonsäuren

Alkylenediamides and Alkylenediisoimides from Ethyleneimino Carboxylic Acids and Ethyleneimino Dicarboxylic Acids Preparation and properties of some alkylenediamides from β-ethyleneiminopropionic acid and ethyleneiminosuccinic acid as well as of two alkylenediisoimides of ethyleneiminosuccinic acid are described.     

Bestimmung aromatischer Fettsäuren in hydrierten cyclischen Fettsäuren

Determination of Aromatic Fatty Acids in Hydrogenated Cyclic Fatty Acids Small amounts of aromatic fatty acids, besides hydrogenated cyclic fatty acids, in an urea non-adduct from hydrogenated fatty acids can not be determined by gas chromatography. A direct determination by UV-spectroscopy is also inaccurate, since the strong end absorption of the carbonyl group makes an evaluation of the aromatic band in the range of 260 to 275 nm difficult. After reducing the acids or esters with lithium aluminium hydride to the corresponding alcohols, a proper quantitative determination of aromatic fatty acids can be carried out even at low concentrations of the latter.     

Oxidatives Verfahren zur Herstellung kurzkettiger Carbonsäuren aus ungesättigten Fettsäuren

Oxidative Procedure for Production of Short-Chain Carbon Acids from Unsaturated Fatty Acids For decades, the oxidation of oleic acid to acelaic and pelargonic acid has been carried out in industrial scale by ozone. The high costs of ozone production are a problematical point in this procedure. Thanks to the high selectivity the procedure is today still economic. Efforts to replace the ozone oxidation by an oxygen one haven't yet led to a procedure which can be applied in industry. In this work the oxygen oxidation of oleic acid with aldehyds as intermediary carrier of oxygen is reported.     

Produkte der Dimerisierung ungesättigter Fettsäuren V: Die Aromatenfraktion dimerer Fettsäuren

Products of Dimerisation of Unsaturated Fatty Acids V: The Aromatic Fraction of Dimeric Acids The aromatic fraction of dimeric fatty acid esters can be separated according to a decreasing grade of unsaturation by HPLC using an UV-recorder. Hydrogenation experiments of the collected fractions allowed the determination of the number of rings. If the aromatic fraction are oxidized with KMnO₄ using a phase-transfer catalyst benzene 1,2,4- and 1,3,5-tri-, 1,2,4,5-and 1,2,3,5-tetra- and the pentacarboxylic acid were obtained as main products. Consequently we have to conclude that the catalyst causes intramolecular extensive migration of alkyl chains. Finally 2,3-dihydrobenzofurantetracarboxylic acids with different position of the carboxylic groups were detected in the mixture of oxidation products.     

Trans-Fettsäuren in Lebensmitteln

Trans Fatty Acids in Foods The fatty acid compositions of the fat in 196 german food samples were analyzed with emphasis on trans components by gas liquid chromatograghy. The range of trans fatty acids (weight percent of methyl esters) in several foods was: margarines 0.6 - 23.5%, shortenings 0.1 - 31.8%, french fried potatoes 508 - 32.8%, cakes and cookies 0 - 15.5%, candies and frostings 0.2 - 15.7%, Crisps and other snacks 0.1 - 20.2%, animal and dairy fats from ruminants. 1.5 - 10.6%, other meat products animals and sausages less than 1%. Teh composition of trans fatty acids differed between hydrogenated fats and ruminant fats. Food processing (except hydrogenation) did not substantially alter the fatty acid composition. The daily intake of trans fatty acids in Germany was estimated by the National Consumption Assay. women consumed 3.4 g/day and men 4.1 g/day. Hydrogenated fats and ruminant fats contributed to the consumption nearly equally. Trans fatty acids influence the plasma lipoprotein levels similarly to saturated fatty acids. The trans fatty acids appear mostly as monounsaturated fatty acids in food composition tables. It seems necessary to distinguish between cis and trans isomers.     

Eigenschaften verzweigter Fettsäuren

Properties of Branched Fatty Acids Physical and chemical properties of branched fatty acids and hydroxy fatty acids were determined and compared with those of n-fatty acids.     

Cyclopentenylfettsäuren im Brennpunkt

Focus on Cyclopentenyl Fatty Acids A Commentary and survey on the nomenclature and configuration of cyclopentenyl fatty acids is given in view of the interest on biologically active compounds derived from such unusual fatty acids. The trivial name alepramic acid is proposed for the C₈-cyclopentenyl fatty acid. Biosynthetic studies suggest Passifloraceae and Turneraceae as potential sources for cyclopentenyl fatty acids in temperate zones.     

Zur Essentialität der Polyenfettsäuren

On the Essential Nature of Polyunsaturated Fatty Acids Several plant oils contain polyunsaturated fatty acids which cannot be synthesized by the human body. They have been recognized as essential nutrients, as characteristic symptoms are caused by deficient intake. The LCP-fatty acids are incorporated into structural lipids and cell membrans and influence directly their properties. LCP-fatty acids are precursors of prostaglandins, lencotrienes and eicosanoid mediators, which intern regulate numerous cell functions. The effects of LCP-fatty acids on pre- and postnatal growth and the nervous system are discussed in detail.     

Übergangsmetallkatalysierte Oxidationen ungesättigter Fettsäuren — Synthesen von Keto- und Dicarbonsäuren

Transition-metal Catalyzed Oxidation of Unsaturated Fatty Acids — Synthesis of Ketocarboxylic Acids and Dicarboxylic Acids Terminal unsaturated C₁₀–C₁₄-fatty acid methylesters (9-decenoic-, 10-un-decenoic-, 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°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°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 and suberic acid were obtained at a conversion rate of 90%. Analogous 10-oxoundecanoic acid led to C₁₀/C₉- and 13-oxotetradecanoic acid led to C₁₃/C₁₂-dicarboxylic acids. The oxidative cleavage of 9-/10-oxostearic acid methylester yielded mixtures of C₈–C₁₀-monocarboxylic acids and methylesters of C₈–C₁₀-dicarboxylic acids.     

Produkte der Dimerisierung ungesättigter Fettsäuren XI: Die Fraktion der alicyclischen Dimerfettsäuren

Products of Dimerisation of Unsaturated Fatty Acids XI: The Fraction of Alicyclic Dimeric Acids Dimeric fatty acids can be separated as their dimethylates by HPLC-chromatography [W. Link, G. Spiteller, Fat Sci. Technol. 92 , 135 (1990)]. The main fraction of dimeric fatty acids obtained by the dimerisation of linoleic acid consists of alicyclic unsaturated dimeric fatty acids with the molecular weights 588 and 590. The structures of these compounds remained unknown until now. This fraction was subjected to hydrogenation, epoxidation and dehydrogenation with SeO₂ and Pd/C. The investigation of the reaction products provided evidence that these dimeric acids are a mixture of the following compounds: Dimeric acids with a 6-ring and one double bond and dimeric acids with two 6-rings and a double bond could be identified. In both types of compounds the double bond can be either situated in the ring as well as outside the ring. In dimeric acids containing two rings this ring system can be condensed or separated by a C-chain. Besides dimeric acids with two 6-rings dimeric acids with one 6-ring and one 5-ring were found. Essential contributions to these deductions were obtained by an investigation of model compounds and model fractions.     

Cyclische Konjudien-Carbonsäuren mit einer semicyclischen Doppelbindung aus der Alkali-Cyclisierung langkettiger Triencarbonsäuren

Cyclic Conjugated Dienoic Carboxylic Acids with a Semicyclic Double Bond from Alkali Cyclisation of Long-Chain Trienoic Carboxylic Acids In the alkali cyclisation of 9-cis, 12-cis, 15-cis-octadecatrienoic acid and of 9-cis, 11-trans, 13-trans-octadecatrienoic acid conjugated dienoic carboxylic acids with the structures 9 to 12 are formed in addition to the ω-(2-alkylcyclohexadienyl)carboxylic acids 3 to 8. The formation of these conjugated dienoic carboxylic acids with semicyclic double bond from the corresponding ω-(2-alkylcyclohexa-3,5-dienyl)carboxylic acids (3) is explained by an ionic shift of the conjugated diene system under the action of the base.     

Produkte der Dimerisierung ungesättigter Fettsäuren III: Trennung dimerer Fettsäuren mittels GC und HPLC — Nachweis aliphatischer und verzweigter Dicarbonsäuren

Products of the Dimerisation of Unsaturated Fatty Acids III: Separation of Dimeric Fatty Acids with the Aid of GC and HPLC — Identification of Branched Aliphatic Dicarboxylic Acids From dimers produced by dimerisation of pure oleic acid we obtain by freezing small amounts of compounds, which can be separated further by GC. The separated compounds are isomers with a molecular weight of 594. They are saturated branched aliphatic dicarboxylic acid esters. They are obviously produced by en-reaction followed by hydrogenation. A much more effective separation than by GC is possible by HPLC, using a detector based on light scattering. Thus the dimeric fatty esters can be separated into four fractions: the first fraction consists of aromatics, the second obviously of alicyclic and unsaturated dicarboxylic acids, the third and fourth consist of aliphatic dicarboxylic acid esters of MW 594. Fatty acids obtained by dimerisation of a starting material rich in linoleic acid contain large amounts of aromatic compounds, those which are obtained by dimerisation of starting material rich in oleic acid contain rather high amounts of aliphatic dicarboxylic acids and practically no aromatic compounds.