Normal fatty acids in sediments

Normal fatty acids have been found by several investigators in a number of sediments ranging in age from Precambrian to Recent. This paper summarizes these occurrences. A variety of molec-ular distributions have been observed. In most sediments, even-carbon-numbered normal fatty acids are much more abundant than those with odd carbon numbers ; in some sediments, however, concentrations of even- and odd-carbon-numbered normal fatty acids are about equal. Normal fatty acids have been postulated as pos-sible precursors for normal paraffin hydrocarbons in petroleum because of 1) structural similarities between the two kinds of molecules, 2) ubiquity of fatty acids in biological materials, 3) fatty acid-normal paraffin relationships in sediments, and 4) distribution of normal paraffins in some crude oils. Evidence suggests that normal fatty acids may be precursors for many normal paraffins of intermediate and high molecular weights found in petroleum. Detailed mechanisms of chemical reactions by which normal paraffins can be de-rived from fatty acids in sediments under geo-logically reasonable conditions have yet to be defined.     

Column types for the chromatographic analysis of oleochemicals

Chromatography has developed into one of the principle methods of analysis of oleochemicals. Gas chromatography has been used extensively for the analysis of long-chain fatty acids as well as for the analysis of triglycerides and plant sterols. In recent years, high pressure liquid chromatography (HPLC) has been used for the analysis of triglycerides as well as for other related materials. Specialized gas chromatography columns have been developed for the separation of long-chain fatty acids such as the methyl esters. These columns have generally used high polarity stationary phases which separate fatty acids by degree of unsaturation. A specialized use of these high polarity stationary phases is separation ofcis-trans isomers as well ascis-cis andtrans-trans isomers. In this paper, packed and capillary columns are compared for the separation of thecis-trans isomers of fatty acid methyl esters prepared from a hydrogenated vegetable oil. For HPLC separations, the presence of a double bond is approximately equivalent chromatographically to shortening the alkyl chain by two carbons. The long-chain polyenic acids or ethyl esters thus elute near but are resolved from the short-chain saturated fatty acids or esters. HPLC is the method of choice for relatively complex, high molecular weight, or labile esters, such as those of retinyl or cholesterol. Glyceryl esters are particularly well resolved by HPLC in terms of both total chain length and degree of unsaturation. This technique is also useful for lipid class separations and for the analysis of modified fatty acid products, such as prostaglandins and related materials. In general, these analyses are conducted with octadecyl bonded phase column packings.     

The determination of the unsaponifiable matter of tall oil distillates

Summary A comparison has been made of extraction efficiency of ethyl ether or petroleum ether in the removal of unsaponifiable matter of tall oil distillates, using the analytical procedures of A.S.T.M. or A.O.C.S. It has been shown that solvents can be used interchangeably. Results were within reasonable accuracy. Synthetic mixtures containing added abietic acid and rosin impurities, when heated at 300°C., increased in unsaponifiable content. Examination of the unsaponifiable extract from several tall oil, fatty acid fractions indicated that it was composed essentially of decarboxylated products of rosin and fatty acids.     

Temperature Effects on the Deacidification of Mixtures of Sunflower Oil and Oleic Acid

Although it is well known that oil temperature is an essential factor for determining the deacidification mass rate and the final free fatty acids content, the influence of the temperature of the gas distillates above the liquid phase in the deodorizer on the oil temperature is much less understood. An extensive study of the effect of the temperature of the oil and of the gas distillates was undertaken in a continuous deodorizer, comparing the results with those obtained using a batch process. Variations in temperature from the temperature obtained without additional heating of the gases to a higher temperature than that of the oil were assayed for the gas distillates at the head of the deodorizer. It was possible to obtain low outlet free fatty acid contents at lower oil temperatures by controlling the overheating of the distillates, even for very high initial free fatty acids content, indicating that this is an essential variable to consider in distillation. However, increasing the temperature of the gas distillates above that of the oil sometimes produces a negative effect in deacidification.     

Comparative performance of steam and nitrogen as stripping gas in physical refining of edible oils

Olive, sunflower, and soybean oils were physically refined in a discontinuous laboratory system with either nitrogen or steam as stripping gas during the deodorization step. Comparative assays were also carried out on olive oil in a 10-MT discontinuous industrial plant. Vaporization efficiency of free fatty acids was calculated, and quality of refined oils and composition of deodorizer distillates were analyzed. Results indicated that, in all assays, the efficiency of free fatty acid distillation was higher when nitrogen was used. The amount of nitrogen needed was much lower than that of steam for refined oils of similar high quality. The results also suggested that the amount of stripping gas had a clear influence on the composition of deodorizer distillates because lower quantities of triglycerides and unsaponifiable matter were found when nitrogen was employed.     

Biooxidation of fatty acid distillates to dibasic acids by a mutant of Candida tropicalis

Fatty acid distillates (FADs) produced during physical refining of vegetable oil contains large amount of free fatty acid. A mutant of Candida tropicalis (M20) obtained after several stages of UV mutation are utilized to produce dicarboxylic acids (DCAs) from the fatty acid distillates of rice bran, soybean, coconut, palm kernel and palm oil. Initially, fermentation study was carried out in shake flasks for 144 h. Products were isolated and identified by GLC analysis. Finally, fermentation was carried out in a 2 L jar fermenter, which yielded 62 g/L and 48 g/L of total dibasic acids from rice bran oil fatty acid distillate and coconut oil fatty acid distillate respectively. FADs can be effectively utilized to produce DCAs of various chain lengths by biooxidation process.     

The examination of fats and fatty acids for toxic substances

The chick edema disease factor was found to be present in a number of distillates and residues that were obtained during the production of commercial fatty acids. The raw materials from which the toxic samples were produced included inedible animal tallows, acidulated vegetable oil foots, and oils recovered from tin plate manufacture. The chick edema factor was found to be present in several oleic acids and in a triolein. Twenty stearic acid samples which were examined were nontoxic. The nonurea adduct-forming fatty acids that were isolated from commercial oleic acids and various distillates and residues from the manufacture of commercial fatty acids were found to be toxic to weanling rats even after hydrogenation. Analysis of the nonurea-adducting monomers that were isolated from a fatty acid by-product distillate indicated the presence of cyclic structures.     

Zur gaschromatographischen Analytik trans-isomerer Fettsäuren auf gepackten Säulen (Silar 10 C,Silar 9 CP,SP 2340, OV 275) sowie auf der mit SP 2340 beschichteten Glaskapillare

Gas Chromatographic Analysis of trans-Isomeric Fatty Acids on Packed Columns (Silar 10C, Silar 9CP, SP 2340, OV 275) and in Glass Capillary Coated with SP 2340 High polar and temperature-resistant cyanopropylsiloxane phases such as Silar 9CP, Silar 10C, SP 2340 and OV 275 have a high selectivity for double bonds and make it possible, for the first time, to separate cis/trans isomeric fatty acid methyl esters on packed columns. The possibilities and limitations for identifying and separating the positional and geometric isomers of monoene, diene and triene fatty acid methyl esters on packed columns are demonstrated by numerous examples and compared with the application range of the SP 2340 glass capillary column. In addition to fatty acid methyl esters, non-derivated fatty acids and alditol acetates resulting from analysis of the sugar moiety of glycolipids and glycoproteins can also be gas chromatographed on these phases.     

Characterization of Flax and Soybean Soapstocks,and Soybean Deodorizer Distillate by GC-FID

Gas chromatography with a flame ionization detector has been used for the characterization of flax and soybean soapstocks and soybean deodorizer distillate. Derivatization by silylation of the samples prior to their injection into a medium polar column enabled a peak resolution of the different components, which led to unambiguous identification of the majority of the components of the samples. The identification and quantification of the fatty acids and sterols in soapstocks and of the fatty acids and tocopherols in deodorizer distillate were successfully achieved. The system has been sensitive enough to characterize 87.5% (mass basis) of the flax soapstock, 95.4% (mass basis) of the soybean soapstock and 83.8% (mass basis) of the soybean deodorizer distillates composition. The method can be safely used for the identification and quantification of most of the components of any type of soapstock and deodorizer distillates.     

Deacidification and recovery of distillates in the physical refining of edible oils

A pilot plant‐scale continuous deodorization installation was developed to simultaneously test several technological changes in the classical deodorization process: use of nitrogen as stripping gas, heating of the gas above the liquid oil, and use of shell‐and‐tube condensers for the recovery of distillates. Deacidification trials were first carried out on mixtures of commercial refined sunflower oil and high‐oleic distillates, and subsequently on bleached olive and sunflower oils. The performance of usual working conditions was analyzed: nitrogen mass flow rate, oil temperature and oil mass flow rate. Marked differences were not observed in the results of the final acidity, compositions of free fatty acids and sterols in the deacidified oil. However, the use of shell‐and‐tube condensers makes it possible to recover liquid distillates in better conditions than in the classical process for their further concentration, while at the same time reducing process pollution.     

Characterization of soapstock and deodorizer distillates of vegetable oils using gas chromatography

Soapstock and deodorizer distillates are complex lipid mixtures that are produced in significant amounts by the vegetable oil refining process. These mixtures contain components such as fatty acids, sterols, squalene and tocopherols that have important commercial value and therefore their characterization and quantification are of interest. We describe here the development of a simple gas chromatography (GC) method based on a silylation derivatization technique coupled with the use of a medium polar column to separate the different classes of fatty compounds in these waste streams. This method is suitable for GC coupled with either a flame ionization detector or a mass spectrometer.     

Möglichkeiten des Umweltschutzes bei der physikalischen Raffination und Fettsäuredestillation

Feasibilities of Environmental Protection Concerning Physical Refining and Fatty Acid Distillation In the present work the accomplishment of the statutory decrees of today concerning waste water and waste air in the field of physical refining, of edible oil deodorization, of straight distillation and the fatty acid fractionation with respect to the necessary need of working stock and devices is investigated. The resulting environmental loads depend beside the tightness of the plant which can be influenced by the apparatus, on the composition and the physical properties of the components of the occurring vapour which is finally exhausted by the vacuum aggregate. In this context the content of inertgas and water on the one hand and their condensation behaviour on the other hand are of special importance. Their correlations are explained by examples of physical refining and deodorization of oils as well as straight distillation and fractionation of fatty acids. As saturated pure products of the higher fatty acids have the highest solidification points, they tolerate the slightest inert gas load in form of carrier steam and should be distilled - if possible - without open steam. The properties of crystallization as well as solubilities in water of the occurring distillates of physical refining, oil deodorization and straight distillation of fatty acids determine the lowest waste gas temperature after condensation which is still allowed, and by that the quantity of light parts which come into the vacuum system by the inert gases inclusive the used carrier steam to condensate there together with the water vapour.     

The enrichment of n−3 polyunsaturated fatty acids using aminopropyl solid phase extraction columns

A rapid, simple and reliable method is described for the preparation of concentrates of methyl or ethyl esters of n−3 polyunsaturated fatty acids by solid phase extraction using aminopropyl bonded silica columns. After applying mixtures of fatty acid esters in hexane, saturated and monounsaturated fatty acid esters are preferentially eluted with hexane whereas polyunsaturated fatty acids (PUFA) can subsequently be eluted with dichloromethane. Concentrates containing 80–90% n−3 PUFA can thus be obtained using fish oil fatty acids esters as a starting material.     

Fatty alcohols

“Fatty” or higher alcohols are mostly C₁₁ to C₂₀ monohydric compounds. In probably no other homologous aliphatic series is the current balance between natural and synthetic products so vividly evident. Natural sources, such as plant or animal esters (waxes), can be made to yield straight chain (normal) alcohols with a terminal (primary) hydroxyl, along with varying degrees of unsaturation. In the past, socalled fatty alcohols were prepared commercially by three general processes from fatty acids or methyl esters, occasionally triglycerides. Fatty acids add hydrogen in the carboxyl group to form fatty alcohols when treated with hydrogen under high pressure and suitable metal catalysts. By a similar reaction, fatty alcohols are prepared by the hydrogenation of glycerides or methyl esters. Fatty alcohols are also prepared by the sodium reduction of esters of fatty acids in a lower molecular weight alcohol. The sodium reduction method was ordinarily too expensive; it was displaced early by the other methods; finally most unsaturated alcohols made by this route were largely replaced. Methyl ester reduction continues to provide perhaps 20% of the saturated fatty alcohols, and selective hydrogenation with the use of special catalysts such as copper or cadmium oxides was developed for the production of oleyl alcohol. Synthetic or petroleum technology for long chain alcohols include the Ziegler process, useful for straight chain, even-numbered saturated products. A second is the carbonylation and reduction of olefins affording medium or highly branched chain alcohols. Paraffin oxidation affords mixed primary alcohols. Fatty alcohols undergo the usual reactions of alcohols. They may be reacted with ethylene oxide to yield a series of polymeric polyoxyethylene alcohols or with acetylene under pressure to yield vinyl ethers or with vinyl acetate to give vinyl ethers.     

A quantitation problem in the open tubular gas chromatography of fatty acid esters from cod liver lipids

Methyl esters of fatty acids of marine origin contain large amounts of highly unsaturated long-chain fatty acids. It is shown that, although esters of saturated and monounsaturated fatty acids can be quantitatively analyzed on open tubular columns with a flame ionization detector there are serious losses of the long-chain highly unsaturated fatty acids of marine oils on the column. Through comparison of chain-length composition and iidine value some correction factors are suggested for the highly unsaturated fatty acids which permit reasonably accurate analyses.     

Reinste Fettsäuren durch neuartige Fraktionierverfahren mit ACV-Hochleistungskolonnen I

Pure Fatty Acids by Novel Process of Fractionation Using High Efficiency ACV Columns A survey on the nature, properties and amounts of natural and synthetic raw materials available for the fatty acids is followed by a comprehensive discussion of conditions employed for preparation of pure individual fatty acids from these mixtures. It is shown that starting from mixtures of fatty acids, their esters as well as alcohols which are available for large scale operations, chemically pure components having purity of over 99% can be obtained. For this purpose, umbrella-type bubble and multi-flow sieve tray constructions developed by ACV, were found to be efficient as separating units with low pressure drop. Taking the examples of processing of coconut and cottonseed oil fatty acids it is shown as to how by an appropriate combination of various columns and evaporators practically any desired purities can be obtained; thereby byproducts and residual components that are present in small amounts do not accumulate. The ACV systems described here are superior to those plants which are operated with stripping steam, especially with respect to low utility costs. These are DM 12.50/t for straight distillate, DM 35.29/t for individual coconut fatty acid fractions with purities above 99.9% and DM 30.96/t for a 99% C₁₈-fraction obtained from cottonseed fatty acids.     

Fatty acid fractionation by column distillation: Purity,energy consumption and operating conditions

This paper discusses the optimal process conditions for production of individual fatty acids of any desired purity up to higher than 99% and describes especially the influences of column internals as well as exchange numbers, reflux ratios and fatty acid residence times at distillation temperatures. The new process conditions are characterized by degasification at low temperatures followed by efficient dehydration together with separation of first cuts at high reflux ratios by short-time dephlegmation. The design of columns for efficiency and low pressure drop is influenced by the thermal properties of crude acids and the quality demands on distillate fractions. Environmental requirements can be met by working without open steam. Bottom temperatures should not exceed 250 C, to prevent thermal degradation of fatty acids as well as corrosion of stainless steel.     

The analysis ofCis-trans fatty acid isomers using gas-liquid chromatography

The geometric isomers of many unsaturated fatty acid methyl esters can be separated using high-resolution gas-liquid chromatography on polyester or Apiezon columns. Separations reported for the geometric isomers of monounsaturated, ricinoleic, linoleic, conjugated, and epoxy fatty acids are reviewed here. New data is presented on the resolution of linolenate geometric isomers on both polyester and Apiezon columns. The separation of methyl oleate and methyl elaidate on a polyester column has also been accomplished. Techniques for preparing and using the high-resolution columns necessary for these separations are reviewed. Presented at the AOCS meeting in New Orleans, La., 1962. Supported in part by a grant from the National Institutes of Health (A-6011).     

用固定床吸附方法脫去液体蜡中的芳香烴

用尿素脱蜡方法生产出来的液体蜡,一般都含有3～10%的芳香烃。欲将此蜡用来作为合成洗滌剂、石油酯增塑剂等轻化工产品的原料,就必须设法降低其中的芳香烃含量到允许范围。前阶段的工作表明,采用固定床循环吸附方法,脱除直馏煤油及其液体蜡中芳香烃是有工业化前途的。本工作就是在以往工作的基础上,进一步探索工艺条件和产品质量之间的初步规律,为中间放大试验提供了操作依据。 试验用原料油有两种:一种是成球法尿素脱蜡中型试验装置生产的液体蜡,馏程210～260℃,芳香烃含量3～5%;另一种是异丙醇尿素脱蜡工业试验装置生产的液体蜡,馏程210～260℃,芳香烃含量8～10%。吸附剂为青岛海洋化工厂生产的粗孔硅胶。隔带剂是90～120℃馏分的溶剂汽汕。脱附剂是工业苯。 试验结果表明,对于芳香烃含量为3～10%的液体蜡,采用固定床循环吸附方法脱去其中芳香烃的最惠工艺操作条件为:加料比（克原科/克硅胶）K=2.68～0.172C_0(C_0表示进料中的芳烃重量百分比）;隔带剂和脱附剂用量,当以体积表示时,均为硅胶在床层中孔隙率的0.7～1.0倍,即1.0～1.5毫升/克硅胶。在最惠操作条件下,当控制去芳烃液体蜡产品中芳香烃含量小于1%时,回收率可达93～95%;副产品芳烃浓缩物纯度较高,折光率（n_D~(20)）可控制在1.5000以上。