Processing for industrial fatty acids - II

Fatty acids are produced industrially from tallow, palm oil, palm stearin, palm kernel oil and coconut oil. The current and future supply situations of these raw materials and market economics favor palm stearin and palm kernel oil as major raw materials for fatty acids. The Malaysian oleochemical industry has adopted high-temperature and high-pressure “splitting” of triglycerides. Variations in product yields occurring in the processing of tallow and palm stearin and of coconut oil and palm kernel oil are indicated. Developments on the enzymic hydrolysis of triglycerides to fatty acids have been made, particularly in Japan. Enzymic hydrolysis at low temperature has the advantage of energy conservation compared to the high-temperature and pressure-splitting process. But enzymic hydrolysis is only applicable to triglycerides of low titre, such as palm kernel oil.     

Studies on nitrosochlorination of olefinic fatty acids: I

Nitrosochlorination of methyl oleate yielded methyl 9(10)-chloro-10(9)-nitrosooctadecanoate, methyl 9(10)-chloro-10(9)-oximinooctadecanoate and an abnormal product 9(10)-chloro-10(9)-nitriminooctadecanoate. A similar reaction with 10-undecenoate yielded a dimer of methyl 10-chloro-11-nitrosoundecanoate, methyl 10-chloro-11-oximinoundecanoate and methyl-10-chloro-11-nitriminoundecanoate. On the other hand, methyltrans-2-doxosenoate reacted reluctantly up to 10%, yielding methyl 2-oximino-3-chlorodocosanoate. All these products have been characterized with the help of compositional and spectral data.     

Search for new industrial oils,IX.Cuphea,a versatile source of fatty acids

Seed oils from five species ofCuphea show three distinct patterns of fatty acid composition.C. hookeriana andC. painteri oils contain ca. 70% caprylic acid,C. ignea and C.llavea oils have over 80% capric acid, andC. carthagenensis oil contains 57% lauric and 18% capric acids. No. Utiliz. Res. and Dev. Div., ARS, USDA ARS, USDA     

Hyperchlorinated fatty acids: I. Tentative methods of synthesis

The hyperchlorination of fatty acids was studied by four methods using mainly stearic acid. This acid was first submitted to the action of nascent chlorine from NaCl electrolysis, for which the best results never exceeded 43% of fixed chlorine (about 6 Cl atoms per mole of acid), with a yield of 30% based on the acid. Stearic acid was also submitted to electric discharges in CCl₄, and so transformed into various chlorinated and unsaturated compounds, which indicate a near simultaneity of chlorination and dehydrochlorination. However, when the time of contact of the acid with the reactive solution was reduced, formation of only saturated chlorinated compounds occurred, of which the chlorine content, in the best case, was 54% (9 Cl/mole). Direct photochlorination of acid without solvent gave a product containing a maximum of 8 Cl atoms per mole (about 50%). Finally, direct photochlorination of the fatty acid in CCl₄ led to a hyperchlorinated acid containing 68.3% Cl (16–17 Cl/mole), and minor, more or less polymerized products. Although the second and third methods readily afford stearic acid chlorinated to the extent of about 50%, this value, corresponding to an average of 0.5 Cl/C atom, appears to be a barrier that can only be overcome by employing photochlorination in an inert solvent, such as CCl₄.     

Marine-derived fatty acids of fish oils as raw materials for fatty acids manufacture

Fish oils, often an abundant source of C₂₀ and C₂₂ fatty acids, could supplement rapessed oil in the manufacture of long chain saturated fatty acids. Herring oil, traditionally the fish oil of choice, is in very short supply due to depletion of fishery stocks. Menhaden oil, when made from fish caught in the Atlantic, could furnish a steady supply with long chain acids at about the 30% level. Oil made from other species such as anchovy or pilchard need further data on fatty acid content and variability. Manufacture of polyunsaturated fatty acids from fish oils is hampered by lack of suitable procedures. Potential markets for fish oil polyunsaturates especially in the pharmaceutical field seem promising.     

Determination of the identity of by-products in the industrial production of saturated fatty acids

A technical product of saturated fatty acids has been analyzed to determine the structure of by-products found in the C_20–22 fatty acids manufactured from fish oil. Short-path distillation of the weakly colored product provided a residue, which was extracted either by supercritical carbon dioxide or by acetone. Extracts and residues were analyzed by size-exclusion chromatography, supercritical fluid chromatography, and by gas chromatography, the latter combined with mass spectrometry and Fourier-transform infrared spectroscopy, and by nuclear magnetic resonance spectrometry. A series of homologs of fatty acid dimers was identified as lactone esters. Each homolog also contained several isomers with a varying number of carbon atoms in the two hydrocarbon chains of the dimers. Trimers, containing yellow components, were also present in small amounts, but the structure of the trimers has not been determined yet.     

Radiolysis of lipids in monolayers. I. Saturated fatty acids

In order to study the effect of molecular orientation on the behavior of lipids when exposed to high energy radiation, model systems of palmitic acid or ethyl palmitate adsorbed as monolayers on silica were irradiated with⁶⁰Co at 25 Mrad under vacuum, and the volatile products compared with those of control samples irradiated in bulk. Major quantitative differences were observed. More of the C _n−1 alkane relative to the shorter-chain members of the homologous series were formed in bulk samples as compared to samples in monolayer. The C _n−2 alkene and C _n aldehyde also were formed in greater quantities in bulk. These observations are explained on the basis of a reduced preferential cleavage near the carbonyl group and a restricted mobility of free radical intermediates, in the case of the monolayers.     

The separation of solid fatty acids from liquid fatty acids by the formation of acid soaps. I. Tallow soaps

The formation of acid soaps has been used successfully for the separation of a mixture of fatty acids into high and low iodine value fractions. The acid soaps of saturated acid can be made to crystallize from water leaving their unsaturated counter parts in solution. Acid soaps of saturated fatty acids are well characterized compounds with the formula R-COOM.R-COOH, where R is a straight alkyl chain, and M is sodium, potassium or ammonium. Optimum crystallization conditions involve a soap concentration of 2–5%, pH adjustment to between 7.0 and 8.0, an initial crystallization temperature not below 25C, and a crystallization period of at least 4 hr during which time cooling to a final temperature of 5–10C must be gradual, and agitation gentle.     

Synthetic fatty acids

Manufacture of fatty acids from petroleum and natural gas is a large industry worldwide and has important implications in the U.S. Eastern Europe produces an estimated 1.2 billion pounds by air oxidation of hydrocarbons compared to an estimated 956 million pounds of natural fatty acids from the U.S., in 1978 (exclusive of tall oil fatty acids). The enormous production of SFA’s in Eastern European countries and in Russia is done by continuous air oxidation of fresh and recycled mixed aliphatic hydrocarbons. Since the products contain proportions of odd-numbered straight chain acids, they have not been used edibly, but have been applied to the manufacture of industrial products such as soap, lubricants, plasticizers and the like. Another European approach (Liquichimica, Italy) for SFA is the caustic fusion (and oxidation) of branched chain alcohols produced by carbonylation and reduction of olefins. American potential technology is diversified but has not yet been translated to production scale, presumably because of the plentiful supply of natural fats and oils that is available.     

Unsaturated fatty acids. I. Low temperature urea complexes of polyunsaturated acids from bovine tissue

Summary A mixture of fatty acids obtained from autolyzed saline extracts of beef testicular tissue was fractionated by crystallization of the urea complexes at 5°, −20°, and −75°C. Fractions rich in docosahexaenoic and in arachidonic acids were obtained as solid complexes. The filtrate remaining after precipitation of the solid urea complexes contained a high percentage of hexaenoic acid of shorter chain length than docosahexaenoic, probably eicosahexaenoic acid. Presented at the fall meeting of the American Oil Chemists' Society, Minneapolis, Oct. 11–13, 1954. Presented in part before the Lipoid Section, IId International Congress of Biochemistry, Paris, France, Sept. 21, 1952.     

Methods for the determination of cyclopropenoid fatty acids. I. Aqueous hydrochloric acid method

An analytical method is described for the estimation of long-chain cyclopropenoid fatty acid derivatives. It is based upon the quantitative addition of a molecule of hydrogen chloride at the cyclopropene ring when the sample is shaken with concentrated hydrochloric acid. The cyclopropenoid content can be calculated, as sterculic acid, from the increase in chlorine content. Epoxy compounds and hydroperoxides interfere and must be removed by one of the accepted pretreatment methods. A laboratory of the So. Utiliz. Res. & Dev. Div., ARS, U.S.D.A.     

Estolides from meadowfoam oil fatty acids and other monounsaturated fatty acids

The formation of estolides was detected during the studies on dimerization of meadowfoam oil fatty acids. By adjusting the reaction conditions, it was possible to produce monoestolides with little dimer or trimer formations. Estolides have potential use in lubricant, cosmetic and ink formulations and in plasticizers. This paper reports the conditions for production of estolides from mixed meadow-foam fatty acids, commercial oleic acid, high-oleic sun-flower oil fatty acids,cis-5,cis-13-docosadienoic acid, petroselinic acid and linoleic acid.     

Metabolism of odd-numbered fatty acids and even-numbered fatty acids in mouse

Fatty acids are converted into energy via beta-oxidation. Although almost all natural occurring fatty acids are even-numbered, there are some odd-numbered fatty acids too. The details of the metabolism rate of odd-numbered fatty acids, however, are not clear. In the present study, we simultaneously administered a triacylglycerol containing four types of labeled even-numbered (palmitic acid and stearic acid) and odd-numbered (pentadecanoic acid and heptadecanoic acid) fatty acids to mice to compare the rates of their metabolism. The rates of metabolism were evaluated based on the accumulation of the labeled fatty acids in the small intestine epithelium, liver, and epididymal fat. Odd-numbered fatty acids accumulated mainly in the epididymal fat. In contrast, there was no accumulation of even-numbered fatty acids observed in the small intestine epithelium, liver, or epididymal fat. These results suggest that odd-numbered fatty acids might not be favorable substrates for beta-oxidation-related enzymes.     

New applications for fatty acids and derivatives

The early development of the American fatty acid industry during 1900–1920 is usually associated with the use of stearic acid in candles for lighting purposes. Today, the use of stearic acid in candle manufacture continues; the volume consumed for this application is not small, but the use is for ornamental, decorative or festival purposes, only incidentally for emergency lighting purposes. When one consideres that most condles consist of 10–20% stearic acid, which improves among other things, the appearance, burning qualities and stiffness of the candle, the volume consumed is appreciable. More than that, the growth rate in this use is impressive. In 1965, it has been estimated that the volume of double-pressed stearic acid that found its wya into candles was 3.5 million pounds. Today (1979) it is conservatively estimated that from 10–12 million pounds are utilized for this purpose. Innovations, such as the development of driples candles, achieved by the incorporation of a somewhat larger proportion of stearic acid to the external wax coat, are now possible uses. Concrete and asphalt are examples of much-used large tonnage materials of construction which have disadvantages in use that can be at least partially or significantly improved through the incorporation of stearic acid or certain other fatty chemicals. An excellent example of the tailor-making of fatty acid derivatives to satisfy an almost desperate need is provided by the development of derivatives suited for the retardation of water evaporation from reservoirs in arid areas. In 1966 it was estimated that the evaporation from large lakes and reservoirs in 17 western states was equivalent to 14 million acre feet, an amount which could ordinarily supply 84 million people annually. The design of water insoluble long chain organic compounds with a hydrophilic group at one terminal position gives products capable of forming monomolecular films which are uniquely suited to solve this problem. Fatty alcohol ethoxylates are only one approach among several. Paper presented at Short Course by S. Eng, Glyco Chemicals, Inc., Painesville, Ohio Representatives of A. Gross Candle Co. (Linden, NJ), Faroy, Inc. (Houston, Texas) and Old Harbor, Inc. (Hyanis Port, MA) supplied part of the information used in this paper.     

Improved procedure for extracting food fatty acids

Estimations of the fat content of food are generally based on the weight of the fraction extracted by a solvent. Unfortunately these solvents extract varying amounts of substances which are nonlipids, and they fail to extract all of the fatty acids, especially those present in complex forms. Though current procedures are simple, they are unreliable. Calories contributed by food fats can be calculated accurately only from data on the total fatty acid content of these foods. An improved method for the complete extraction of food fatty acids is described. This method involves an extraction of food samples with chloroform: methanol (2∶1) both before and after treatment with 2 N hydrochloric acid in methanol, removal of the solvent from the combined extracts, and then extraction with chloroform. This method was compared with the AOAC method in the analysis of 18 foods for fatty acid content. The values obtained by the new method were higher in every case, and significantly higher in most cases, due primarily to a more complete extraction of the bound fatty acids. The usefulness of the new method in the routine analysis of foods was demonstrated in 58 additional food samples.     

Production of fatty alcohols from fatty acids

Detergent-range alcohols from natural feedstock can be produced by high pressure hydrogenation of either methyl esters or fatty acids. The increasing quantities of fats and oils on the world market secure a reliable and economically priced material. Although fatty acid is an abundant worldwide commodity, most alcohol producers hydrogenate methyl esters, because direct hydrogenation of fatty acids is difficult as the catalyst is sensitive to acid attack. The process described here makes it possible to hydrogenate fatty acids directly to alcohols of high quality without prior esterification. The reaction takes place in the liquid phase over a fine-grained copper chromite slurry in a single reactor vessel. A special reactor design with an optimum arragement of the feeding nozzles causing an appropriate circulation of the reacting components inside the reactor facilitates the rapid “in situ” esterification reaction. This minimizes the free fatty acid concentration in the reactor to nearly zero. This results in a low consumption of catalyst. The most important advantages of the process are: direct feed of fatty acids of various origins, use of reasonably priced raw materials such as soapstock fatty acids and lower grade tallow acids, no process steps with methanol, and excellent economics. The process is industrially proven.