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1.
The reduction of α- and β-eleostearic acids with hydrazine has been studied. GLC analysis of the products coupled with oxidative
degradation using permanganate-periodate reagent showed an initial attack mainly at the 9,10 and 13,14 bonds in the triene
without change in configuration. The method should be useful in structural studies on conjugated fatty acids.
Issued as NRC No. 7987. 相似文献
2.
Z. M. Zarins J. L. White R. K. Willich R. O. Feuge 《Journal of the American Oil Chemists' Society》1982,59(12):511-515
The hydrogenation of cyclopropenoid acids and their relative reactivities during hydrogenation as compared to linoleic and
oleic acids were examined. Pure methyl sterculate and purifiedSterculia foetida oil and its methyl esters, which have a cyclopropene content more than 60 times that of cottonseed oil, were used for the
hydrogenation experiments. Nickel, palladium and platinum catalysts were used. The effect of temperature and type of catalyst
were demonstrated in a series of hydrogenation experiments of safflower andS. foetida oil mixtures, and methyl oleate and methyl dihydrosterculate mixtures. Partial hydrogenation of methyl sterculate formed
as many as twenty compounds in addition to the cyclopropenoid derivatives. Most of these compounds were monounsaturated. The
cyclopropene group hydrogenated very readily compared to the 9,12-diene system in linoleate. The cyclopropane group obtained
by hydrogenating the cyclopropenoid acids group was quite resistant to further attack by hydrogen and nickel catalyst had
little effect. With palladium catalyst, a temperature of 180 C was necessary for the reaction to go to completion. Platinum
in acetic acid was a good system for hydrogenolysis of the cyclopropane group at 80 C.
Retired. 相似文献
3.
Copper oleate and cadmium oleate catalysts have been replaced by other metal compounds. Silver was the only metal which could
be substituted for copper in the ratio range studied. Using nickel oleate, the degree of saturation of the double bond decreased
with increasing cadmium oleate concentration. No comparable substitute was found for Cd. The composition of the final components
is influenced by the use of a paraffinic solvent, which also has an effect on the saturation of the double bond. An explanation
is given for the behavior of the catalyst when the reaction is not selective and is carried out in a paraffinic solvent. The
catalytic system Ag/Cd soaps was also studied kinetically and analytically. The results show that the mechanism of the reaction
using silver soap is identical with the one using copper soap. 相似文献
4.
The catalyst system containing copper and cadmium oleates as used in selective hydrogenations was analyzed. The reddish brown reaction mixture as such and after precipitation by alcohol was subjected to polarographic, spectroscopic, x-ray and electron-microscopic analysis. The conclusion drawn was that the mixture is a heterogeneous system. From an electron micrograph it was observed that the average particle size is 48 Å. It was also possible to determine the mean degree of oxidation of copper in the precipitate, the results indicating that the copper is in its metallic state. Cadmium is present as cadmiumoleate, which stabilizes the copper colloid during the reaction. 相似文献
5.
Randomly rearranged soybean oil (Iodine Value 128) was hydrogenated with samples being taken at decrements of 10 I.V. units.
The composition of the fatty acids occupying the various positions of the triglyceride molecules of these fats was determined.
The results demonstrate that the position an unsaturated fatty acid occupies on a triglyceride molecule does not influence
its rate of hydrogenation. 相似文献
6.
Gotoh N Moroda K Watanabe H Yoshinaga K Tanaka M Mizobe H Ichioka K Tokairin S Wada S 《Journal of oleo science》2008,57(5):293-299
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. 相似文献
7.
8.
H. Fineberg 《Journal of the American Oil Chemists' Society》1979,56(11):805A-809A
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. 相似文献
9.
Production of fatty alcohols from fatty acids 总被引:3,自引:0,他引:3
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. 相似文献
10.
Separation of fatty acids 总被引:1,自引:0,他引:1
K. T. Zilch 《Journal of the American Oil Chemists' Society》1979,56(11):739A-742A
Fatty acid separations which do not involve fractional distillation are discussed. Various methods of separating fatty acids
from a practical point of view and the most salient facts of each process are described. 相似文献
11.
Arthur A. Spector 《Lipids》1999,34(1):S1-S3
All fatty acids have important functions, but the term “essential” is applied only to those polyunsaturated fatty acids (PUFA) that are necessary for good health and cannot be completely synthesized in the body. The need for arachidonic acid, which is utilized for eicosanoid synthesis and is a constituent of membrane phospholipids involved in signal transduction, is the main reason why the n-6 class of PUFA are essential. Physiological data indicate that n-3 PUFA also are essential. Although eicosapentaenoic acid also is a substrate for eicosanoid synthesis, docosahexaenoic acid (DHA) is more likely to be the essential n-3 constituent because it is necessary for optimal visual acuity and neural development. DHA is present in large amounts in the ethanolamine and serine phospholipids, suggesting that its function involves membrane structure. Because the metabolism of n-6 PUFA is geared primarily to produce arachidonic acid, only small amounts of 22-carbon n-6 PUFA are ordinarily formed. Thus, the essentiality of n-3 PUFA may be due to their ability to supply enough 22-carbon PUFA for optimal membrane function rather than to a unique biochemical property of DHA. 相似文献
12.
Hydrogenation of fatty acid methyl esters to fatty alcohols at supercritical conditions 总被引:2,自引:0,他引:2
Sander van den Hark Magnus Härröd Poul Møller 《Journal of the American Oil Chemists' Society》1999,76(11):1363-1370
Extremely rapid hydrogenation of fatty acid methyl esters (FAME) to fatty alcohols (FOH) occurs when the reaction is conducted
in a substantially homogeneous supercritical phase, using propane as a solvent, over a solid catalyst. At these conditions,
the limitations of hydrogen transport are eliminated. At temperatures above 240°C, complete conversion of the starting material
was reached at residence times of 2 to 3 s, which is several orders of magnitude shorter than reported in the literature.
Furthermore, formation of by-products, i.e., hydrocarbons, could be prevented by choosing the right process settings. Hydrogen
concentration turned out to be the key parameter for achieving the above two goals. As a result of the supercritical conditions,
we could control the hydrogen concentration at the catalyst surface independently of the other process parameters. When methylated
rapeseed oil was used as a substrate, the hydrogenation catalyst was deactivated rapidly. However, by using methylated sunflower
oil, a catalyst life similar to that obtained in industrial processes was achieved. Our results showed that the hydrogenation
of FAME to FOH at supercritical conditions is a much more efficient method than any other published process. 相似文献
13.
14.
Selim M. Erhan Robert Kleiman Terry A. Isbell 《Journal of the American Oil Chemists' Society》1993,70(5):461-465
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. 相似文献
15.
The kinetics and mechanism of the Cu and Cd-soap-catalyzed hydrogenation of oleic acid have been studied. The reaction is
first order in Cd and H2, and also first order in Cu if the double bond is completely preserved during reduction of the carboxyl group to the hydroxyl
group. It will deviate from this order if the selectivity is lower owing to an increased Cu concentration. The reaction rate-determining
step is independent of the Cd concentration. Its activation energy, of 13.4 kcal/mole, corresponds to that of the chemisorption
of hydrogen on Cu. Unsaturated and saturated fatty acids of the same chain length have the same reaction rate. A decrease
of the chain length causes a decrease in the reaction rate and in the final degree of conversion. Water and low molecular
weight acids have an inhibitory effect on the reaction. A reaction mechanism is proposed which is based on the assumption
that cadmium oleate plays a double role: it stabilizes the copper sol and is intermediate for the hydrogenation. 相似文献
16.
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。 相似文献
17.
Koji Yoshino Yasushi Kajiwara Naotake Takaishi Yoshiaki Inamoto Jiro Tsuji 《Journal of the American Oil Chemists' Society》1990,67(1):21-24
Hydrogenation of carboxylic acids to alcohols at low temperature and under low pressure was achieved by using a new catalyst
system, a rhenium-osmium bimetallic catalyst. The most active catalyst was prepared by the reductionof the corresponding metal
oxides with hydrogen in the presence of succinic acid. Decanoic acid was hydrogenated to decanol in high conversions at 25∼100
atm and 100∼120°C. Decane was formed as a by-product by overreduction of the alcohol. The selectivity of alcohol was improved
by the addition of thiophene as a modifier of the catalyst. 相似文献
18.
P. Kashulines S. S. H. Rizvil P. Harriott J. A. Zollweg 《Journal of the American Oil Chemists' Society》1991,68(12):912-921
The viscosities of several types of lipids saturated with supercritical carbon dioxide (SC-CO2) were measured with a high-pressure capillary viscometer. Oleic acid and linoleic acid were evaluated from 85 to 350 bar
at 40 and 60°C. The more SC-CO2-soluble methylated derivatives of these fatty acids were evaluated from 90 to 170 bar at 40 and 60°C. The complex mixture
of anhydrous milk fat (AMF) was evaluated from 100–310 bar at 40°C. The viscosities of the methylated fatty acids saturated
with SC-CO2 decreased between 5 and 10 times when the pressure increased from 1 to 80 bar, followed by a further decrease by a factor
of 2 to 3 when the pressure was increased from 80 to 180 bar. The viscosities of the fatty acids and AMF saturated with SC-CO2 had viscosity reduction similar to the methylated fatty acids between 1 and 80 bar, but they decreased much less between
80 and 350 bar. At constant pressure, the viscosity of the fatty acids and AMF decreased with increasing temperature, whereas
the viscosity of the methylated fatty acids increased with increasing temperature. The lipid/SC-CO2 mixtures were Newtonian, and their viscosities were best interpreted by using the mass concentration of dissolved SC-CO2 in the lipids and the pure component viscosities. 相似文献
19.
M. E. Stansby 《Journal of the American Oil Chemists' Society》1979,56(11):793A-796A
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. 相似文献
20.
Furan fatty acids (F‐acids) are heterocyclic lipid components with a furan moiety in the centre of the molecule. Reports on F‐acids in the literature are rather scarce, although they are considered as particularly valuable food ingredients. F‐acids occur as minor compounds in the lipids of different food samples. Despite the low concentrations, some studies produced evidence that the F‐acids are excellent radical scavengers and thus are able to protect polyunsaturated fatty acids from lipid peroxidation. Accordingly, they may play a currently underrated and largely overlooked positive role in human nutrition. The limited data available result from difficulties in the analysis of these trace compounds. F‐acids in food can hardly be determined without selective enrichment and the use of gas chromatography with mass spectrometry for their determination. The lack of reference standards is a further drawback that hampers the exact assessment of the actual relevance of F‐acids in human nutrition. 相似文献