Einfluß von Licht und Tocopherolgehalt auf die Oxidationsstabilität von Fettsäuremethylestern

Influence of light and contents of tocopherols on the oxidative stability of fatty acid methyl esters The oxidative stability of different plant oil based fatty acid methyl esters can be estimated by determining the induction period with the active oxygen method. Measuring the volatile and oil soluble acids for a long period preceding the induction period shows that the values are approaching a certain limit. Even if the esters do not differ dramatically in the composition of fatty acids it is a fact that the different production processes influence the amount of tocopherols significantly. The exclusion of light is more crucial than the exclusion of air when storing plant oil based fatty acid esters.     

Neue Fettderivate aus der Esterkondensation von Fettsäuremethylestern

New Fatty-Derivatives from the Ester Condensation of Methyl Esters of Fatty Acids The preparation of products of ester condensation from methyl esters of fatty acids is discussed and the chemistry of the derivatives as well as the possibilities of their application is reported.     

Kontinuierliche Alkoxylierung von Fettsäuren,Fettalkoholen und Fettaminen

Continuous Alkoxylation of Fatty Acids, Fatty Alcohols and Fatty Amines A continuous process for the alkoxylation of long chain carboxylic acids, alcohols and amines in the presence of alkaline catalysts in a pilot plant scale is reported. The reactions are carried out in a short-time reactor using a combination of different parameters in a temperature range of 250°–350° C, at a pressure of 50–100 at and a duration of 10–80 sec. The process with a high space-time yield is especially suitable for the manufacture of low alkoxylated products.     

Gaschromatographische und dünnschichtchromatographische Untersuchung von Fettsäuren: Die Anwendung von gepackten Glaskapillarsäulen zur Trennung von cis- und trans-ungesättigten Fettsäuren

Gas Chromatographic and Thin-Layer Chromatographic Studies on Fatty Acids: The Application of Packed Glass Capillary Columns for Separation of cis- and trans-Unsaturated Fatty Acids from Saturated Fatty Acids Packed glass capillary columns were used for the quantitative determination of trans- and cis-unsaturated fatty acids in the presence of saturated fatty acids by gas chromatography. The fatty acids were analyzed as methyl esters after interesterification of the triglyceride samples. The conversion of glyceryl esters of fatty acids into methyl esters could be followed using short GC columns and by thin-layer chromatography.     

Verfahren und Anlagen zur Fraktionierung von synthetischen Fettsäuren

Processes and Plants for the Fractionation of Synthetic Fatty Acids Synthetic fatty acids, prepared by oxidation of paraffins, can be used to save valuable edible fats. Fractional distillation of these fatty acids enable their manifold application. For this, the paraffins have to fulfil certain criteria of quality. In a multiple stage vacuum fractionation process provided with material balance regulator, high boiling complex mixtures can be processed to distillates of high purity. Such a multi-column plant is equipped with stills, fractional columns and rectifying columns, and the plant is controlled by feeding machines. Many years of experience and production data have shown that synthetic fatty acid distillates can be produced economically and these products meet the technical requirements of soap and detergent industry.     

Analytik und Biophysik von verzweigtkettigen Fettsäuren in Lipiden

Analytics and biophysics of branched fatty acids in lipids . Objects of our investigations are long chain fatty acids with methyl groups in different positions and fatty acids with a different length of the sidegroup in α-position. The separation of racemic branched fatty acid methyl esters by gas chromatography on a chiral column depends on the structure of the branched fatty acid. Diastereomeric amides and phosphatidylcholines with α-branched fatty acid residues were separated preparatively. The branched fatty acids were incorporated into 1,2-diacyl-, 1-acyl-2-hexadecyl- and 2-acyl-1-hexadecyl-glycerophosphocholines and characterized by differential scanning calorimetry and X-ray diffraction.     

Aspekte bei der Hydrierung von Fetten und Fettsäuren

Aspects of Hydrogenation of Fats and Fatty Acids Hydrogenation of fat products is of great significance, both for human and animal nutrition as well as for technical purposes. In the area of nutrition, adequate food for the increasing world population is unthinkable without utilization of all fat resources, that can be made available as food fats only after catalytic hydrogenation. In the area of technical use, a similar development is observed owing to shortage of mineral oils. Thus, fatty alcohols derived from vegetable oils and waxes can already compete in price with fully synthetic fatty alcohols derived from mineral oils. In the past 70 years of hydrogenation of fats till the present time, catalysts based on nickel have been most commonly used. In addition, small proportions of catalysts based on copper and noble metals have also been used. Homogenous catalysts have been used very recently. The present communication deals primarily with the hydrogenation of neutral fats and fatty acids using nickel catalysts. The aspects of selectivity and isomerization in the partial hydrogenation of neutral fats are discussed. In the hydrogenation of fatty acids and their derivatives, emphasis is laid on other factors, such as activity, poisoning and acid resistance of the catalyst. These factors are discussed.     

Untersuchungen über die Entstehung von Kohlenwasserstoffen in UV-bestrahlten Fettsäuren und Fettsäure-Estern

Studies on the Formation of Hydrocarbons in Fatty Acids and Fatty Acid Esters Irradiated with UV Rays The investigation of volatile compounds in unsaponifiable matter and in steam distillates of UV-irradiated saturated fatty acids and fatty acid esters has shown that by irradiation in the presence of air as well as under vacuum, along with other substances, unsaturated hydrocarbons are formed. They are most probably 1,2 alkenes whose chains are shorter than the corresponding fatty acids by 2 C-atoms. The volatile compounds in the unsaponifiable matter of the UV-irradiated oleic acid comprise predominantly of carbonyle compounds.     

Wasserstofferzeugung für die Hydrierung von Fetten und Fettsäuren

Production of Hydrogen for the Hydrogenation of Fats and Fatty Acids A process is described for the production of highly pure hydrogen from hydrocarbons, such as natural gas, liquefied gas and light petroleum. The process consists of following three steps: 1. Desulfurization of the starting material; 2. Conversion of hydrocarbons into permanent gases by splitting with steam at high temperatures; 3. Separation of other gases from hydrogen by adsorption. This process has been tested commercially. With increasing cost of transport, and owing to regulations for the transport of hydrogen, which are difficult to fulfil, the aforesaid process offers an attractive alternative to the consumer of hydrogen. Cost of investment, energy consumption and economy of the process are dealt with.     

Massenspektrometrische Identifizierung von verzweigtkettigen Fettsäuren und Alkoholen aus Bürzellipiden

Mass Spectrometric Identification of Branched Chain Fatty Acids and Alcohols from Preen Gland Lipids The preen gland lipids of some birds were isolated, the waxes separated and resolved into fatty acid and alcohol fractions. The alcohols were oxidised with chromic acid to form the corresponding fatty acids. After methylation with methanolic HCl, the fatty acid methyl esters were investigated by capillary gas chromatography-mass spectrometry. The fatty acids possess mainly mono-, di- and trimethyl branched structures, the branching positions being located preferentially on C–2/–3/–4/–6, C–2,4/–2,6/–2,8/–3,7 C–2,4,6/–2,6,10 and C–6/C–10 or C–14. The mass spectrometric fragmentations which are significant for the structure elucidation of these fatty acid methyl esters are discussed in detail. The investigations indicate a correlation between the composition of the birds to defined orders of the natural system (chemotaxonomy).     

Anzahl der Isomeren von polysubstituierten Fettsäuren

Number of Isomers in Polysubstituted Fatty Acids The number of positional and optical isomers of mono-, di-, tri-, tetra-, penta- and hexa-substituted polyhydroxy and polymethyl fatty acids upto C₃₂H₆₄O₂ (non-branched basic chain) was calculated. The n-fatty acid C₃₂H₆₄O₂ having 6 substituents (excluding the substitution at the terminal CH₃-group of the fatty acid) gives 539 680 positional isomers, 6 methyl groups yield 34 201 440 optical isomers and 6 OH groups 37 995 520 optical isomers.     

Untersuchungen über die Entstehung von Kohlenwasserstoffen in erhitzten gesättigten Fettsäuren und Fettsäureestern

Studies on the Formation of Hydrocarbons in Fatty Acids and Fatty Acid Esters on Heating The investigations on the volatile compounds of the unsaponifiable matter and the steam distillate of heated saturated fatty acids have shown that on heating in the presence of air, along with other substances, hydrocarbons having a chain length 1 to 2 C atoms shorter than the corresponding fatty acids are formed. The splitting proceeds so slowly in the case of esters that even after 4 hrs of heating at 160°C no reaction products could be detected. By heating palmitic acid under the same conditions, except that vacuum was employed, no perceptible quantities of hydrocarbons were found.     

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.     

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.     

Wiederveresterung von Konzentraten mehrfach ungesättigter Fettsäuren

Reesterification of Polyunsaturated Fatty Acid Concentrates Fatty acids of the n-6 series such as γ-linolenic acid (C18:3) and of the n-3 series such as α-linolenic (C18:3), stearidonic (C18:4), eicosapentaenoic (C20:5) and docosahexaenoic acid (C22:6) are of great nutritional interest. These acids can be obtained by urea fractionation in concentrated form from natural sources like blackcurrant seed oil, borage oil, evening primrose oil, linseed oil and fish oil, respectively. Certain dietary applications require a reesterification of these fatty acid concentrates with glycerol to triglycerides. Industrial scale methods of reesterification could not be applied as such for the present polyunsaturated fatty acid systems. Therefore reaction conditions had to be adapted to these highly sensitive substances. A one step reesterification method, using ZnCl₂ as catalyst, was optimized for three different fatty acid concentrates composed of the above mentioned acids. Under the given reaction conditions, it could be observed that α-linolenic acid is much more sensitive to polymerization than γ-linolenic acid. Different purification methods of the crude triglycerides have been evaluated, obtaining best results by liquid chromatography methods, in particular with respect to decoloration of the final products.     

Untersuchungen zur kontinuierlichen Hydrierung von Ölen und Fettsäuren III Kinetik der Härtung freier Fettsäuren des Sojaöls

Investigations of the Continuous Hydrogenation of Oils and Fatty Acids III: Kinetic of Free Fatty Acid Hardening of Soya Bean Oil The kinetic of continuous hardening of free fatty acids of soya bean oil was investigated in a reactor with solid porous catalyst using the trickling procedure. Under the given arrangement and continuous hydrogen excess (continuous phase) hydrogenation of fatty acids follows the kinetic I. order. Temperature influences are much stronger using Ni-catalyst in ihe phase of equalized properties than using fresh catalyst. Pressure influences the reaction rate in both cases in a positive way. Its effect however in connection with temperature rise is much stronger with catalyst in the phase of equalized properties, that is the catalyst with lower activity.