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.     

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.     

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.     

Gas-liquid chromatographic analysis of cyclopropene fatty acids

A gas-liquid chromatographic method is described for the quantitative estimation of cyclopropene fatty acids as their methyl mercaptan derivatives. This method estimates individual cyclopropene acids as well as normal and cyclopropane acids. Nine seed oils were analyzed for their cyclopropene fatty acid content. Evidence was obtained for the presence of a cyclopropene fatty acid of shorter chain length than malvalic inAlthaea rosea cav and one with a higher chain length than sterculic inBombacopsis glabra seed oil. This method is less accurate for cottonseed oil than for the other oils tested because of the appearance of some unsymmetrical peaks of unknown origin. The mercaptan derivatives of the cyclopropene acids may be isolated by silver ion thin-layer chromatography. Small amounts of cyclopropane fatty acids were found in a number of the oils analyzed for cyclopropene fatty acids. Presented at the AOCS meeting, Chicago, October 1964.     

n−3 polyunsaturated fatty acids and coronary thrombosis

Studies of Greenland Eskimos showed that a very high intake of marine n?3 fatty acids markedly inhibited platelet reactivity and suggested that intake of these fatty acids might prevent coronary thrombosis. Later studies with lower, more practical doses of n?3 fatty acids also have shown a platelet inhibitory effect of n?3 fatty acids, albeit fairly marginal. Furthermore, n?3 fatty acids have little effect on measures of blood coagulability and may slightly decrease fibrinolysis. In animal models, n?3 fatty acids often have been shown to inhibit thrombosis, but again the doses have tended to be very high. Finally, there has been little effect of (low-dose) n?3 fatty acids in clinical trials in humans on the incidence of myocardial infarction. Overall, there is little evidence for a major antithrombotic effect of practical doses of n?3 fatty acids on coronary thrombosis. This does not exclude a beneficial effect of n?3 fatty acids on coronary heart disease as suggested from clinical trials, but the major effect may be antiarrhythmic rather than antithrombotic.     

Efficient synthesis of fatty monoglyceride sulfates from fatty acids and fatty acid methyl esters

An efficient high yield synthesis of fatty monoglyceride sulfates from fatty acids or fatty acid methyl esters, glycerine and chlorosulfuric acid in chloroform using stoichiometric amounts of reagents was developed. Sodium coco monoglyceride sulfate was prepared in 79% yield with 93% purity from coco fatty acids. Similarly, sodium palm kernel monoglyceride sulfate in 57% yield and sodium palm monoglyceride sulfate in 71% yield were obtained from palm kernel fatty acid methyl esters and palm fatty acids, respectively. This new synthetic method produced better quality products with higher active ingredients and improved yields without having to use such cost prohibitive, high purity, fatty acid monoglycerides, and it reduced the undesirable aqueous sodium sulfate by-product by 60% over a current commercial process. The product’s composition and purity were confirmed by cationic titration, infrared and C-13 NMR spectroscopy.     

Comparison of catabolism rate of fatty acids to carbon dioxide in mice

The catabolism rates of a medium chain fatty acid (octanoic acid), an even‐numbered fatty acid (palmitic acid), and odd‐numbered fatty acids (pentadecanoic acid and heptadecanoic acid) in mice were compared using stable isotope (¹³C) labeled fatty acids and isotope‐ratio MS (IRMS). The catabolism rates of respective fatty acids were evaluated by the ratio of ¹³C and ¹²C in carbon dioxide expired from mice. The results show that the catabolism rate of octanoic acid is three times faster than that of palmitic acid. This result is in agreement with previous knowledge that medium chain fatty acids are easily beta‐oxidized as compared to long chain fatty acids. The catabolism rates of odd‐numbered fatty acids such as pentadecanoic acid and heptadecanoic acid were significantly lower as compared to those of even‐numbered fatty acids such as palmitic acid. This finding supports our previous report that odd‐numbered fatty acids are easily accumulated into body fat. The high accumulation of odd‐numbered fatty acids in body fat would be a direct result of their low beta‐oxidizability. Practical applications: ¹³C‐labeled fatty acids were administered to mice and the rates of ¹³CO₂ formation were compared among medium chain, even‐numbered, and odd‐numbered fatty acids using IRMS. We found that the catabolism rates of odd‐numbered fatty acids such as pentadecanoic acid and heptadecanoic acid were significantly lower in comparison to those of even‐numbered fatty acids such as palmitic acid. These findings could be valuable for the development of the lipid metabolism field.     

Recovery of fatty acid lights from still vapors

A fatty acids still operating primarily on coconut oil fatty acids has two condensers in series to condense the top product. Nonetheless, until recently 1% to 2% of fatty acid lights normally passed through to the hot well. Here the caproic, caprylic and capric acids dissolved in the warm water and these dissolved acids ultimately found their way to the plant effluent stream where they contributed to the biochemical oxygen demand loading. Early in 1969 a Croll-Reynolds Scrub-Vactor was placed in operation to remove fatty acids from the vapors leaving the still. A normal scrubber installation could not be employed because of the volatility of the lights, but a modification was devised in which coconut oil low in free fatty acids is sprayed into the scrubber. The coconut oil is removed continuously at such a rate that the free fatty acids content of the oil does not build up to over 10% to 15%. This material then goes to the fat splitter. By this means 80% of more of the fatty acids are removed from the vapor stream with resulting reduction in polution of plant aqueous effluent and collection of salable fatty acid lights.     

The fatty acids of degras

Degras contains a complex mixture of lipids comprised of branched and normal chain fatty acids, hydroxy acids, sterols, sterol esters and long chain wax esters. There are no glycerides in degras. This paper is a report on the composition of the branched and normal chain fatty acids. Preparative techniques of thin-layer chromatography were used to isolate the fatty acids from the other lipid classes. Gas chromatography was used on three different stationary phase separations of the fatty acid methyl esters. Identifications of the composition were based on a combination of techniques and known standards. Authorized for publication on April 20, 1965, as paper No. 3003 in the journal series of The Pennsylvania Agricultural Experiment Station.     

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.     

Use of acetyl chloride/methanol for assumed selective methylation of plasma nonesterified fatty acids results in significant methylation of esterified fatty acids

The albumin-bound nonesterified fatty acid pool in plasma, which represents a very small percentage of total plasma fatty acids, has previously been quantitated by a variety of methods. In the present study we determined that the nonesterified fatty acid concentrations in the plasma, quantitated by a popular method using acetyl chloride and methanol which is reported to be specific for methylation of nonesterified fatty acids in the presence of esterified fatty acids (i.e., without prior isolation of the plasma non-esterified fatty acids), were significantly overestimated due to cleavage and methylation of esterified fatty acids. Quantitation of the contaminating fatty acid from the esterified pool demonstrated that the amount of fatty acid cleaved from the esterified pool was enough to exceed the entire mass of nonesterified fatty acids. As an established method for comparison, we isolated nonesterified fatty acids from the plasma by thin-layer chromatography prior to methylation, using a number of simple precautions to limit oxidation. By performing all thin-layer chromatography steps in an atmosphere of nitrogen and by including fatty acid standards in the plasma with 0,1, 2 or 4 double bounds, we were able to accurately and reproducibly determine the concentration of nonesterified fatty acids in the plasma, including arachidonate. We demonstrated that no oxidation occurred in the thin-layer chromatographic isolation of homonesterified fatty acids and that the coefficients of variation for repeat measurements of the same sample were <11% using our reference method. Our data indicate that the use of acetyl chloride and methanol for assumed selective methylation of plasma nonesterified fatty acids results in significant methylation of esterified fatty acids.     

The implications of recent research on trans fatty acids

The link between the intake of industrially produced trans fatty acids and risk of coronary heart disease (CHD) has been reviewed recently. The authors concluded that elimination of industrially produced trans fatty acids from the USA diet might avert 22% of the 1.2 million CHD events in the USA every year. Denmark has introduced legislation which limits the trans fatty acid content of oils and fats destined for human consumption to 2% of total fatty acids. This has reduced trans fatty acid intake in Denmark to insignificant levels and it will be interesting to see what effects this has on risk of CHD. By contrast in the USA the FDA has chosen the labelling option which puts the onus on the consumer to make the right food choices although New York City has adopted a more interventionist approach in its restaurants and food outlets. The Danish approach is far more effective as can be seen from the amounts of trans fatty acids present in French fries and chicken nuggets purchased from McDonalds and KFC in the two countries.     

New process for the production of branched-chain fatty acids

Fatty acids are the primary natural starting materials for the production of surfactant and detergent molecules. Derived from vegetable (oil) and animal (fat) triglyceride sources, the fatty acids are linear aliphatic carboxylic acids. Industrial interest in branched-chain fatty acids is driven by the needs for products with enhanced performance benefits including higher solubility, ease of handling, better hard water tolerance, and improved oxidative stability. Therefore, catalytic processes have been developed for the conversion of linear fatty acids to branched ones. High yields of branched acids are obtained from unsaturated fatty acids over acidic zeolites, particularly those with large pores. Fatty esters also are readily isomerized to branched ones by means of the same catalyst and process. It is postulated that the isomerization of fatty acids proceeds through three- and four-membered ring carbocation intermediates formed inside the largepore zeolites. This is supported by evidence of methyl and ethyl branching in the primary and final products. The total number of carbon atoms in the fatty acid molecule is unchanged. Surfactants derived from branched fatty acids show favorable physical properties, including a lower viscosity and improved handling, even as intended performance characteristics are maintained.     

Metabolism of brain glycolipid fatty acids

The metabolism of the fatty acid moieties of brain cerebrosides, sulfatides, and gangliosides is reviewed and discussed. The methodology involved in the isolation of the fatty acids is described briefly. It seems clear now that most of these acids are made by chain elongation of intermediate length fatty acids by addition of acetate residues. The unsaturated acids are made by desaturation of the intermediate length acids (palmitic, heptadecanoic, stearic) followed by chain elongation. The hydroxy acids are made directly from the corresponding nonhydroxy acids, saturated, unsaturated, and odd-numbered. All the hydroxy acids undergo oxidative decarboxylation to yield fatty acids containing one less carbon atom. The odd-numbered acids are also made from propionate, which is elongated to intermediate length acids and then to longer acids. The major intermediate length “primer” acid seems to be palmitate, but there is evidence that the stearate used for cerebroside synthesis is also madede novo from acetate. The ganglioside fatty acids were found to turn over somewhat faster than the other fatty acids. Two metabolic pools for the cerebroside acids were found, one with a very high turnover rate, the other with a very low turnover rate. Presented at the Prof. Ernst Klenk Symposium on Glycolipids and the Nervous System, AOCS meeting, Houston, April 1965.     

Cyclic fatty acids: Separation from straight-chain fatty acids by urea adducting

A mixture containing 37% cyclic and 63% straight-chain fatty acids, made by high-temperature treatment of linseed oil fatty acids with alkali, was separated by the urea adduct method to give unsaturated cyclic fatty acids (nonadduct) in 95% purity and 90–95% yeild. Previous reports from this Laboratory describe a process for separating cyclic fatty acids from stearic acid by hydrogenation followed by crystallization at −40C. The urea adduct method avoids hydrogenation and low-temperature crystallization, and furthermore, unsaturated cyclic and unsaturated straight-chain products can be recovered as individual fractions. Then, by readducting the unsaturated straight-chain fatty acid fraction, the small amounts of palmitic and stearic acids are removed leaving an unsaturated fraction containing oleic, nonconjugated and conjugated linoleic and some unsaturated cyclic fatty acids. Presented at AOCS Meeting, Los Angeles, April 1966. No. Utiliz. Res. Dev. Div., ARS, USDA.     

代谢工程改造酵母生产多不饱和脂肪酸的研究进展

多不饱和脂肪酸因其在食品和医药领域的广泛作用而得到人们极大的关注,当前利用微生物发酵生产多 不饱和脂肪酸具有诸多优点,由于酵母生产迅速且生物量较高,利用酵母生产多不饱和脂肪酸已成为人们关注 的热点。本文综述了代谢工程改造酵母生产多不饱和脂肪酸的研究进展,以常规酵母-酿酒酵母和非常规酵母- 解脂耶氏酵母为例,介绍了酵母菌中多不饱和脂肪酸的代谢途径、酵母产油脂的生化机制、代谢工程改造酵母 产多不饱和脂肪酸以及不饱和脂肪酸积累对酵母耐受性的影响。以后研究工作的重点是进一步加强对酵母生产 多不饱和脂肪酸的机理研究,并以此为来指导代谢工程改造酵母生产多不饱和脂肪酸。     

Physical properties of fatty acids

Summary The chemical composition, molecular configuration, and crystal structure of fatty acid molecules contribute to the more than twenty distinct physical properties associated with this class of organic compounds. This discussion will be limited to only a few of these fatty acid properties and will include melting and solidification phenomena, vapor pressure-boiling point relationships and solubility behavior of fatty acids.     

Conversion of palmitate to unsaturated fatty acids differs in a Neurospora crassa mutant with impaired fatty acid synthase activity

The Neurospora crassa cel (fatty acid chain elongation) mutant has impaired fatty acid synthase activity. The cel mutant requires exogenous 16:0 for growth and converts 16:0 to other fatty acids. In contrast to wild-type N. crassa, which converted only 42% of the exogenous [7,7,8,8-²H₄]16:0 that was incorporated into cell lipids to unsaturated fatty acids, cel converted 72%. In addition, cel contains higher levels of 18:3^δ9,12,15 than wild-type, and synthesizes two fatty acids, 20:2^δ11,14 and 20:3^δ11,14,17, found at only trace levels in wild-type. Thus, the Δ15-desaturase activity and elongation activity on 18-carbon polyunsaturated fatty acids are higher for cel than wild-type. This altered metabolism of exogenous 16:0 may be directly due to impaired flux through the endogenous fatty acid biosynthetic pathway, or may result from altered regulation of the synthesis of unsaturated fatty acids in the mutant.     

New developments in synthetic fatty acids

New developments in synthetic fatty acids have occurred in the last few years in Russia, Japan, the United States and Canada. In 1959 Russia decided to replace 40% of natural fatty acids in soaps with synthetic fatty acids. In 1966, 548 million pounds of C₅–C₃₀ synthetic fatty acids were produced including 288 million pounds of C₁₀–C₂₀ fatty acids. Forty million pounds of fatty acids are converted directly to the fatty alcohols for detergent use. A conservative estimate predicts that one billion pounds of synthetic fatty acids will be produced in Russia by the end of the current five-year program. Reports say that the Japanese have been interested in the oxidation of not only paraffin hydrocarbons but naphthenic petroleum hydrocarbons as well. Production of lower homology fatty acids up to butyric acid is being seriously considered in Japan. In America the most likely syntheses aside from “oxo” syntheses being considered for the manufacture of products like lauric acid is the carboxylation of the Ziegler intermediates prepared from ethylene polymerization. Some data on the current and future coconut oil consumption by major end-use for Canada and the United States are presented. Synthetic lauric acid is predicted for 1970 in the United States. Prepared from an address given at a meeting of the Northeast Section, New York, June 1968.     

由直链不饱和脂肪酸异构制备支链脂肪酸的研究进展

介绍了直链不饱和脂肪酸制备支链脂肪酸的研究现状,综述了脂肪酸异构机理,异构催化剂如白土催化剂、沸石催化剂,催化剂的筛选原则,着重讨论了各种常用沸石对于脂肪酸异构反应不同的影响以及现有的合成工艺。分析了脂肪酸的分离技术,包括精馏分离法、溶剂结晶法、尿素包结法、超临界流体萃取法的优缺点,指出沸石催化生产支链饱和脂肪酸的关键问题是需要解决混合脂肪酸作为原料反应的选择性问题,其相关的基础性工作,如更明确的反应机理和催化剂结构参数对反应的影响,仍是将来的研究方向。