Strukturaufklärung cyclischer Fettsäure-methylester I: Zusammensetzung von Gemischen aromatischer Fettsäure-methylester aus den Cyclisierungs- und Aromatisierungsprodukten von Leinöl- und Holzöl-Fettsäure-methylestern,Linolsäure und Linolsäure-methylester

Structure Determination of Methyl Esters of Cyclic Fatty Acids I: Composition of Mixtures Containing Methyl Esters of Aromatic Fatty Acids Obtained from Products of Cyclisation and Aromatisation of Linoleic Acid, Methyl Linoleate and Methyl Esters of Linseed and Tung Oil Fatty Acids The composition of methyl ester mixtures of aromatic fatty acids obtained by alkaline cyclisation and catalytic aromatisation of linoleic acid and methyl linoleate was determined. All the isomeric o-alkyl substituted methyl esters of aromatic fatty acids (I) (n = 0 to 11) could be identified by IR-, UV-, mass-spectrometry, gas-chromatography and by comparison with synthetic substances. The distribution of isomers in mixtures obtained by various procedures was determined by gas-chromatography. o-dodecyl phenol was found to be a by-product in the catalytic aromatisation of free linoleic acid.     

Strukturaufklärung cyclischer Fettsäuremethylester V: Massenspektrometrie isomerer Phenylundecansäure-methylester

Elucidation of Structure of the Methyl Esters of Cyclic Fatty Acids V: Mass-Spectrometry of Isomeric Methyl Esters of Phenyl Undecanoic Acid Isomeric phenyl undecanoic acids obtained by the Friedel-Crafts reaction of benzene with 10-undecenoic acid were investigated as methyl esters using capillary gas-chromatography – mass spectrometry (GC-MS). The isomers could be identified as methyl esters of (5-), 6-, 7-, 8-, 9- and 10 phenyl undecanoic acids. The fragmentation due to electron bombardment is discussed.     

Zur Autoxydation ungesättigter Fettsäure-Ester in Gegenwart von Methanol und Protonen I: Die Autoxydation einfach ungesättigter Fettsäure-methylester

Autoxidation of Unsaturated Fatty Acid Esters in the Presence of Methyl Alcohol and Protons I. The Autoxidation of Monounsaturated Fatty Acid Methyl Esters The methyl esters of oleic, elaidic, 2-octadecenoic and 3-nonenoic acids were autoxidised in presence of methyl alcohol and protons. The amount of the primarily formed isomeric hydroperoxides could be estimated by the quantitative determination of the aldehydic degradation products. The acidic and the Fe⁺⁺ induced degradation of oleic acid methyl ester hydroperoxide mixture was employed for the same purpose. The α-methylene mechanism is also applicable under the conditions under which preferentially the oxygen initiated autoxidation takes place.     

Zur Tocochromanol- und Fettsäureanalytik im Fisch

Analysis of Tocochromanols and Fatty Acids in fish Tocochromanols and lipids are quantitatively extractable from homogenate of the edible part (muscle and skin) of carp with dichloromethane and methanol at room temperature. The contents of tocopherols and tocotrienols are determinable directly in the lipid extract dissolved in n-hexane by HPLC (fluorescence detection). The fatty acids of the polyenic acid rich lipids are derivated to the methyl esters. Transesterification is carried out with methanolic potassium methylate solution, followed by esterification of possibly present free fatty acids with boron trifluoride-methanol, at room temperature. The fatty acid methyl esters (C8 :0 to C22:6 ω3) are separated and quantified by capillary gas chromatography on the station ary phase FFAP.     

Untersuchungen über die Struktur dimerer Fettsäuren I: Struktur dimerer Ölsäure-methylester

Investigation on the Structure of Dimeric Fatty Acids, Part I: Structure of Dimeric Methyl Oleates Monoenoic as well as dienoic dimers were synthesized from methyl oleate and compared thin-layer chromatographically with a mixture of dimers obtained from thermally treated methyl oleate. By this means it was made to appear very likely that the unsaturated components of the mixture of dimers comprise monoenoic and dienoic dimers. The mixture contained, beside 30% saturated dimers, 30% dienoic and 40% monoenoic dimers. By analysis with mass- and NMR-spectra an unequivocal characterization of the ring system in saturated dimers was not possible. The mechanism of the dimerisation is discussed.     

Untersuchungen über die Struktur dimerer Fettsäuren V: Thermische und peroxidkatalysierte Dimerisierung von Linolensäure-methylester

Investigations on the Structure of Dimeric Fatty Acids V: Thermal and Peroxide-Catalyzed Dimerisation of Methyl Linolenate By heating methyl linolenate at 280° C in high vacuum 26% dimers resulted besides 2% hydrocarbons, 24% methyl esters of monocarboxylic acids, 46% polymers and methyl esters of dicarboxylic acids. The dimers comprise of mainly penta-, tetra-, tri- and bicyclic types. Dehydro dimers obtained by catalytic action of di-tert-butyl peroxide on methyl linolenate at 140° C were mainly of the acyclic type containing 6 double bonds.     

Cis-trans-Isomerisierung ungesättigter Fettsäuren im Laufe der Alkydharz-Herstellung

Cis-trans Isomerisation of Unsaturated Fatty Acids during the Preparation of Alkyds We studied the influence of the preparation conditions of alkyd resins with the help of infrared spectroscopy of soya and linseed oil on the cis-trans-isomerisation of the unsaturated fatty acids present. The most important of all conditions was the temperature. The higher content of trans-isomers can be seen in the properties of alkyd resins.     

Untersuchungen über die Struktur dimerer Fettsäuren IV: Struktur dimerer 9c,12c-Octadecadiensäure-methylester

Investigations on the Structure of Dimeric Fatty Acids, Part IV: Structure of Dimeric Methyl-9^c,12^c-octadecadienoates After 65 hrs. of heating methyl-9^c,12^c-linoleate at 280°C under argon, dimers in 24% yield could be isolated, which can be hydrogenated to completeness. Mass spectrometry of the mixture of dimers and those of their hydrogenated products showed that the dimers comprise of saturated tricyclic, monounsaturated bicyclic, diunsaturated monocyclic and triunsaturated acyclic dimers, all having the mol. weight 588, and dehydrodimers having mol. weight 586. Acyclic dehydrodimers with four double bonds could not be detected. Mass spectrometry of the conversion products of the dimers with monoperphthalic acid showed that the dehydrodimers occur predominantly as bicyclic and tricyclic compounds with two double bonds and one double bond respectively. Diels-Alder dimers with tetrasubstituted cyclohexene structure are not formed in the thermal dimerisation of methyl-9,12-linoleate under aforesaid conditions. The possible path of formation of the dimers via radical intermediates is discussed.     

Zur Autoxydation ungesättigter Fettsäure-Ester in Gegenwart von Methanol und Protonen II: Die Autoxydation von Linolsäure-methylester

Autoxidation of Unsaturated Fatty Acid Esters in Presence of Methanol and Protons II: The Autoxydation of Methyl Linoleate The amounts of the 7 possible isomeric hydroperoxides formed by the autoxidation of methyl linoleate in presence of methanol and protons are determined by quantitative estimation of the 2,4-dinitrophenylhydrazones of the saturated and unsaturated aldehydes and aldehyde esters contained in the cleavage products. The quantitative separation of the 2,4-dinitrophenylhydrazones from the osazones was accomplished by paper, partition and thin-layer chromatography. 70% of the hydroperoxides formed were derived from the conjugated fatty acids. The C–H-bonds of the 8th C-atom are less reactive towards oxygen than those of the 14th C-atom. The α-methylene group of the shorter alkyl rest is preferentially autoxidised.     

Einfluß gestaffelter Rapssaatanteile im Legehennenfutter auf das Fettsäurenmuster des Eifettes unter besonderer Berücksichtigung der polyungesättigten Fettsäuren

Influence of Graded Levels of Rape Seed in Laying Hen Diets on the Fatty Acid Composition of the Yolk Fat with Special Consideration of the Polyunsaturated Fatty Acids Technical treated rape seed was evaluated as feed ingredient for laying hens and the influence of rape oil on the fatty acid composition of the egg yolks was also investigated. Rape seed levels of 7.5%, 15% and 22.5% were fed both to brown and white laying hens (Lohmann Brown, LB, and Lohmann Selected Leghorn, LSL, resp.). A depression in performance was recorded only with the highest rape inclusion level for the parameters feed conversion (LB-hens) and daily egg production (LSL-hens). The fatty acid composition of the egg yolk was influenced in a dose-response related manner. The percentage of the saturated fatty acids decreased with increasing levels of rape seed whereas the mono-unsaturated fatty acids and the n-6 polyunsaturated fatty acids were hardly influenced. The level of the polyunsaturated n-3 fatty acids was characterized by a strong dose-dependent increase. In addition, long chained polyunsaturated fatty acids of the n-3 family - not present in rape oil - were detected in the yolks.     

Regioselektive C-H-Funktionalisierung von Fettsäuren und Fettsäuremethylestern

Regioselective C-H-Functionalization of Fatty Acids and their Methyl Esters Fatty acids and thier methyl esters can be chlorinated preferentially at the terminal methylene groups with N-alkylchloroamines in sulfuric acid. With capric acid and its methyl ester the optimal reaction conditions for the selective chlorination were elaborated and then transferred to longer fatty acids up to stearic acid. The influence of the solvent, the temperature and the nature of different chlorinating reagents on the selectivity was studies. The capillary GC/MS-analysis of the isomeric chlorinated fatty acids is described.     

Untersuchungen über die Struktur dimerer Fettsäuren III: Zur Frage der Diels-Alder-Reaktion bei der thermischen Polymerisation von Linolsäure-methylester

Investigations on the Structure of Dimeric Fatty Acids, Part III: Diels-Alder-Reaction in the Thermal Polymerization of Methyl Linoleate To start with, the literature involving the role of Diels-Alder-reaction in the thermal polymerization of methyl linoleate is summarized. It is shown experimentally that methyl-9^c,12^c-linoleate undergoes conjugation only in the presence of free radicals. In this reaction, radicals with conjugated diene systems are formed, which, in contrast to molecules with conjugated diene systems, do not enter into Diels-Alder-reaction. The conjugated radicals get stabilized at 135°C under the formation of acyclic dimers.     

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.     

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.     

Auswirkungen oxidierter Fettsäuren des Mischfutters auf die Carotinoideinlagerung im Eidotter

Effects of Oxidized Fatty Acids of Mixed Feed on Interstitial Carotinoids in Egg Yolk It was the target of investigations to test whether a different degree or course of oxidation of the fat/oil contained in mixed feed influences the deposit of carotinoids in egg yolk. The results show a significant influence of fat oxidation on carotinoid deposit in egg yolk. The yolk colour decreases with increasing peroxide value and is improved at lower peroxide values. Especially oils with high contents of unsaturated fatty acids cause a diminished carotinoid deposit in egg yolk. By addition of antioxidants the fatty acid oxidation can be delayed. Basic feed components among others bad tapioca meal with high lipoxygenase activity can have an important influence too on peroxide formation and with that on yolk colouring.     

Untersuchungen über die Struktur dimerer Fettsäuren II: Herstellung und Strukturaufklärung von Diels-Alder-Dimeren aus 9t, 11t-Octadecadiensäure-methylester

Investigations on the Structure of Dimeric Fatty Acids, Part II: Preparation and Structure Determination of Diels-Alder Dimers from Methyl-9^t,11^t-Octadecadienoate From the reaction product resulting from 6 hrs of treatment of methyl-9^t,11^t-octadecadienoate at 250°C under argon 35% by weight of dimers were obtained. The thin-layer chromatogram of the dimers showed the presence of four components, which could be isolated in preparative scale as colourless liquids. All these components exhibited a refractive index n_D²⁰ = 1.4762 ± 0.0002, iodine value 86 ± 1 and mol weight 588. The mass spectra corresponded to those of tetrasubstituted cyclohexene derivatives. Hence, the product is a mixture of various positional isomers. The complete hydrogenation of the dimers could be accomplished only after the addition of a small quantity of perchloric acid. This behaviour appears to be typical for cyclohexenoic dimers with long chain rests.     

Die prozentuale Zusammensetzung der freien Fettsäuren im Vergleich zum Fettsäuremuster nach Verseifung (Gesamtfettsäuren) bei einigen frischen und gelagerten tierischen Lebensmitteln

Percent Composition of Free Fatty Acids of a Few Fresh and Stored Animal Food Products in Comparison to Their Fatty Acid Pattern after Saponification Depot fat and muscle fat of fresh and stored chickens as well as beef tallow and milk fat were analysed after saponification by gas-liquid chromatography as their methyl esters. The free fatty acids of the same fats were absorbed on alumina and examined for their composition after desorption in the same way. The amount of free fatty acids after lipolysis was not identical with the percentage of fatty acids of the fats. Palmitoleic-, oleic-, and linoleic acid showed an increase, but palmitic and stearic acid a decrease of their amounts in the liberated acids in comparison to the composition of the fatty acids of neutral fats. A remarkable amount of volatile acids could be detected in the free fatty acids only.