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1.
Eberhard Fehling 《Journal of the American Oil Chemists' Society》1995,72(3):355-359
Gel permeation chromatography of hydroxylated fatty acids (HOFA), prepared from various plant oils by a novel technical process,
showed the presence of considerable amounts of estolides formed by intermolecular esterification of the HOFA. Thin-layer chromatographic
fractionation followed by gas chromatography of the fractions revealed that the nonpolar estolides contain predominantly saturated
fatty acids esterified tothero-9, 10-dihydroxy octadecanoic acid or dihydroxy tetrahydrofuran octadecanoic acids, e.g., 9,12-dihydroxy-10, 13-epoxy octadecanoic
acid and 10,13-dihydroxy-9, 12-epoxy octadecanoic acid. The fractions of polar estolides consist mainly of intermolecular
esters of the above dihydroxy fatty acids. 相似文献
2.
In this study it is shown that the epoxide derivative of oleic acid, methyl 9,10-epoxyoctadecanoate, is readily hydrolyzed
to a diol when exposed to a commercial preparation of neutral alumina. Comparison of 1H and 13C NMR spectra of the diol with those of standards showed that the product was the threo isomer. When methyl 9, 10–12,13-diepoxyocta-decanoate was treated with alumina, a mixture of dihydroxy-tetrahydrofuran regioisomers,
methyl 9,12-epoxy-10,13-dihydroxystearate and methyl 10,13-epoxy-9,12-dihydroxystearate, was obtained. These results show
that alumina is an unsuitable support for epoxidation catalysts. However, alumina-catalyzed hydrolysis of fatty epoxides is
an efficient way to synthesize polyhydroxy materials, and these materials are suitable for several industrial applications. 相似文献
3.
Sukhprit Singh Sonia Mahajan Harpal Kaur 《Journal of the American Oil Chemists' Society》1999,76(1):103-107
A tetrahydrofuran ring containing oligoethylene glycol ethers has been synthesized from the seed oil of Vernonia anthelmintica. The seed oil was reacted with mono-, di-, and triethylene glycols in the presence of boron trifluoride etherate, followed
by saponification and esterification (MeOH/H+). The oligoethylene glycol ethers thus obtained were epoxidized with perbenzoic acid. The 9,10-epoxy oligoethylene glycol
ethers so formed were intramolecularly cyclized in dry benzene using boron trifluoride etherate as a catalyst to yield the
tetrahydrofuran ring containing oligoethylene glycol ethers; methyl 9,12-epoxy, 10-hydroxy-13-[2-hydroxyethyl-1-oxy]; methyl
9,12-epoxy,10-hydroxy-13-[2-hydroxy-3-oxapentyl-1-oxy] and methyl 9,12-epoxy,10-hydroxy-13-[8-hydroxy-3,6-dioxaoctyl-1-oxy]octadecanoates,
respectively. 相似文献
4.
E. Fehling S. Schönwiese E. Klein K. D. Mukherjee N. Weber 《Journal of the American Oil Chemists' Society》1998,75(12):1757-1760
A method has been developed for the preparation of highly pure malvalic (cis-8,9-methyleneheptadec-8-enoic) and sterculic (cis-9,10-methyleneoctadec-9-enoic) acid methyl esters starting from Bombax munguba and Sterculia foetida seed oils. The methyl esters of these oils were prepared by sodium methylate-catalyzed transmethylation followed by cooling
(6°C) the hexane solution of crude methyl esters and separation of insoluble fatty acid methyl esters by centrifugation in
the case of B. munguba and by column chromatography in the case of S. foetida. Subsequently, the saturated straight-chain fatty acid methyl esters were almost quantitatively removed by urea adduct formation.
Finally, methyl malvalate and methyl sterculate were separated from the remaining unsaturated fatty acid methyl esters, in
particular methyl oleate and methyl linoleate, by preparative high-performance liquid chromatography on C18 reversed-phase using acetonitrile isocratically. Methyl malvalate and methyl sterculate were obtained with purities of 95–97
and 95–98%, respectively. 相似文献
5.
Kenneth D. Carlson Robert Kleiman Marvin O. Bagby 《Journal of the American Oil Chemists' Society》1994,71(2):175-182
Lesquerella gordonii (Gray) Wats andLimnanthes alba Benth. (Meadowfoam) are species being studied as new and alternative crops. Triglyceride oil from lesquerella contains 55–60%
of the uncommon 14-hydroxy-cis-11-eicosenoic acid. Meadowfoam oil has 95% uncommon acids, includingca. 60%cis-5-eicosenoic acid. Both oils are predominantly unsaturated (3% saturated acids), and have similar iodine values (90–91),
from which oxirane values of 5.7% are possible for the fully epoxidized oils. Each oil was epoxidized withm-chloro-peroxybenzoic acid, and oxirane values were 5.0% (lesquerella) and 5.2% (meadowfoam). The epoxy acid composition of
each product was examined by gas chromatography of the methyl esters, which showed that epoxidizedL. gordonii oil contained 55% 11,12-epoxy-14-hydroxyeicosanoic acid, and epoxidized meadowfoam oil contained 63% 5,6-epoxyeicosanoic
acid, as expected for normal complete epoxidation. Mass spectrometry of trimethylsilyloxy derivatives of polyols, prepared
from the epoxidized esters, confirmed the identity of the epoxidation products and the straightforward nature of the epoxidation
process. Synthesis and characterization of these interesting epoxy oils and derivatives are discussed. 相似文献
6.
R. Agarwal A. Rauf M. Khan J. Mustafa M. Ahmad 《Journal of the American Oil Chemists' Society》1990,67(12):932-936
Chlorophenylselenenylation methodology is shown to cause cyclization of naturally occurring β- and γ-hydroxyolefinic acids.
The phenylseleno-substituted 1,4-epoxides (tetrahydrofurans) thus obtained are oxidized by m-chloroperbenzoic acid (m-CPBA).
Reaction of phenylselenenyl chloride with methyl 12-hydroxyoctadec-cis-9-enoate (methyl ricinoleate) gave methyl 9,12-epoxy-10-phenylselenenyloctadecanoate in useful yields. A similar reaction
of phenylselenenyl chloride with methyl 9-hydroxyoctadec-cis-12-enoate afforded a quantitative yield of methyl 9,12-epoxy-13-phenylselenenyloctadecanoate. Oxidation of selenium-containing
1,4-epoxy esters by m-chloroperbenzoic acid (1 equivalent) yielded the respective olefinic 1,4-epoxy esters, while 5 equivalent
m-CPBA afforded the corresponding oxirane esters of epoxytetrahydrofurans in high yields. The structure of the individual
reaction products have been established from analytical and spectral data and corroborated by a study of their mass spectra. 相似文献
7.
Pierre Blaise Marie Farines Jacques Soulier 《Journal of the American Oil Chemists' Society》1997,74(6):727-730
Gorlic, chaulmoogric and hydnocarpic fatty acids, specific to the seed oil of the genus Hydnocarpus sp. (Flacourtiaceae), are determined only with difficulty by gas chromatography. These fatty acids were isolated in their
methyl ester form by a combination of different chromatographic techniques (thin-layer chromatography/Ag+ and high-pressure liquid chromatography). The proton and carbon nuclear magnetic resonance analysis of these fatty acid methyl
esters showed some characteristic signals of the cyclopentenyl ring. The presence of these signals in the proton and/or carbon
nuclear magnetic resonance spectrum of an oil thus will allow us to confirm the presence of these cyclopentenyl fatty acids
in lipids. 相似文献
8.
V. Spitzer K. Aitzetmüller K. Vosmann 《Journal of the American Oil Chemists' Society》1996,73(12):1733-1735
The fatty acids from the seed oil ofBernardia pulchella (Euphorbiaceae) have been analyzed by gas chromatography (GC) and GC-mass spectrometry (MS) analysis of their methyl esters.
Vernolic acid is the main compound (91%), along with other usual fatty acids. In addition to the quantitation by GC analysis,1H-nuclear magnetic resonance (NMR) signals from the seed oil have been used to estimate the total epoxy fatty acid content.
The structure of vernolic acid has been proven by spectroscopic methods (infrared,1H, and13C-NMR) and by GC-MS analysis of the corresponding silylated hydroxy-methoxy derivative. The 4,4-dimethyloxazoline derivatives
of the fatty acid mixture have also been examined by GC-MS, and it was shown that this derivazation reaction is not suitable
for the structure analysis of vernolic acid. 相似文献
9.
In the presence of an immobilized lipase fromCandida antacrtica (Novozym 435R) fatty acids are converted to peroxy acids by the reaction with hydrogen peroxide. In a similar reaction, fatty acid esters
are perhydrolyzed to peroxy acids. Unsaturated fatty acid esters subsequently epoxidize themselves, and in this way epoxidized
plant oils can be prepared with good yields (rapeseed oil 91%, sunflower oil 88%, linseed oil 80%). The hydrolysis of the
plant oil to mono- and diglycerides can be suppressed by the addition of a small amount of free fatty acids. Rapeseed oil
methyl ester can also be epoxidized; the conversion of C=C-bonds is 95%, and the composition of the epoxy fatty acid methyl
esters corresponds to the composition of the unsaturated methyl esters in the substrate.
Based partly on a lecture at the 86th AOCS Annual Meeting & Expo, San Antonio, Texas, May 7–11, 1995. 相似文献
10.
A. Chaudhry R. Kleiman K. D. Carlson 《Journal of the American Oil Chemists' Society》1990,67(11):863-866
Routine analysis of fatty ester fractions ofLesquerella fendleri oil suggested the presence of epoxy compounds and other minor components. By a combination of open silica column and high
performance liquid chromatography (HPLC) fractionations of the methyl esters prepared from the oil, these constitutents were
isolated and then characterized by thin-layer chromatography-mass spectrometry (GC-MS—electron ionization, EI, and chemical
ionization, CI) and nuclear magnetic resonance (NMR—1H and13C). Three epoxy acids, 15,16-epoxy-9,12-octadecadienoic, 9,10-epoxy-12-octadecenoic and 9,10-epoxy-octadecanoic, were found.
Hydroxy acids present included a C-22 homologue of lesquerolic acid (16-hydroxy-12-docosenoic acid) and 14,15-dihydroxy-tricosanoic
acid. Other minor ocmponents included four sterols, brassicasterol, campesterol, β-sitosterol and stigmasterol, and a series
of saturated and unsaturated fatty acids up to C30.
Visiting postdoctoral scientist sponsored by the government of India. 相似文献
11.
Laila H. Ali Gerald Angyal Carol M. Weaver Jeanne I. Rader Magdi M. Mossoba 《Journal of the American Oil Chemists' Society》1996,73(12):1699-1705
The totaltrans fatty acid content of 18 food products was determined, after acid hydrolysis, extraction and methylation of fatty acids,
by gas chromatography with a polar 100% cyanopropylsiloxane capillary column and by single-bounce horizontal attenuated total
reflection spectroscopy (SB-HATR). Thetrans fatty acid methyl esters (FAME) of 9-hexadecenoate (9t-16:1), 9-octadecenoate (9t-18:1), and 9,12-octadecadienoate (9t,12t-18:2) were identified by comparison of their retention times with those of known standards and quantitated. The isomersc,t- andt,c-18:2 were identified from their published retention times and included in the quantitation oftrans FAME. Neat 50-μL portions of the FAME that were used for gas-chromatographic analysis also were analyzed by SB-HATR. This
technique requires neither weighing nor quantitative dilution of test portions prior to spectroscopic quantitation of isolated
double bonds oftrans configuration. A symmetric 966-cm−1 absorption band on a horizontal background was obtained from unhydrogenated soybean oil FAME as the reference material. For
9 of 11 products withtrans fat content>5% of total fat, results obtained by SB-HATR were higher than those obtained by gas chromatography. Results obtained
by the gaschromatographic procedure were slightly to significantly higher than those obtained by SB-HATR for the six foods
in whichtrans fat content was <5% of total fat. 相似文献
12.
E. L. Schneider Sook P. Loke D. T. Hopkins 《Journal of the American Oil Chemists' Society》1968,45(9):585-590
A method is described for the analysis of cyclopropenoid fatty acids in oils. The method consists of reacting the methyl esters
of the cyclopropenoid fatty acids with silver nitrate in methanol to form ether and ketone derivatives. The derivatives formed
from the cyclopropenoid fatty acids are separated from the methyl esters of the normal fatty acids by gas-liquid chromatography
on a 15% diethylene glycol succinate column. The method is applicable to oils containing from 0.01% to 100% of cyclopropenoid
fatty acids. The derivatives of oils containing lew levels of cyclopropenoids are separated from the normal methyl esters
by alumina chromatography prior to gas-liquid chromatography. Studies on the quantitative aspects of the derivative formation,
alumina chromatography, and gas-liquid chromatography are reported. Analyses for total cyclopropenoid fatty acid content of
cottonseed oil andSterculia foetida oil by the gas-liquid chromatographic and hydrobromic acid titration procedures showed good agreement. Replicate analyses
of a sample ofSterculia foetida oil for malvalic and sterculic acid gave coefficients of variation of 6.04% and 1.17%, respectively. 相似文献
13.
Volker Spitzer Werner Tomberg Mônica Zucolotto 《Journal of the American Oil Chemists' Society》1996,73(5):569-573
Besides some usual fatty acids, the seed oil ofSabastiana brasiliensis (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectroscopy) of α-parinaric acid (cis, trans, trans, cis-9, 11, 13, 15-octadecatetraenoic acid). The fatty acids were analyzed by gas chromatography and gas chromatography/mass spectrometry
as their methyl esters. The structure of α-parinaric acid was proven by a combination of chemical and spectroscopic methods,
conducted with the crude oil, the methyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the1H and13C nuclear magnetic resonance (NMR) shifts of α-parinaric acid was carried out by two-dimensional NMR experiments
Presented in part at the 21st world Congress and Exhibition of the International Society for Fat Research (ISF), October 1–6,
1995, The Hague, The Netherlands. 相似文献
14.
V. Spitzer S. A. de L. Bordignon E. P. Schenkel F. Marx 《Journal of the American Oil Chemists' Society》1994,71(12):1343-1348
In addition to some usual fatty acids, the seed oil ofJodina rhombifolia (Santalaceae) contains nine acetylenic fatty acids [9-octadecynoic acid (stearolic acid) (1.1%),trans-10-heptadecen-8-ynoic acid (pyrulic acid) (20.1%), 7-hydroxy-trans-10-heptadecen-8-ynoic acid (2.3%),trans-10,16-heptadecadien-8-ynoic acid (0.7%), 7-hydroxy-trans-10,16-heptadecadien-8-ynoic acid (0.1%),trans-11-octadecen-9-ynoic acid (ximenynic acid) (20.3%), 8-hydroxy-trans-11-octadecen-9-ynoic acid (12.2%),trans-11,17-octadecadien-9-ynoic acid (1.5%), 8-hydroxy-trans-11,17-octadecadien-9-ynoic acid (1.3%), 9-hydroxystearic acid (<0.1%) and 9,10-epoxystearic acid (0.7%)]. The fatty acids
have been analyzed by gas chromatography/mass spectrometry of their methyl ester and 4,4-dimethyloxazoline derivatives. The
hydroxy fatty acid methyl esters have been examined also as trimethyl-silyl ethers. Furthermore, the fatty acid methyl esters
(FAME) have been fractionated according to their polarity (FAME-A: nonhydroxy; FAME-B: hydroxy fatty acids) and to their degree
of unsaturation (FAME-A1/A2; FAME-B1/B2) by preparative thin-layer chromatography and argentation chromatography, respectively.
All of these fractions have been analyzed by ultraviolet and infrared spectroscopy, and the fractions FAME-A and FAME-B have
been analyzed further by nuclear magnetic resonance (1H,13C, 2D H/C, attached proton test) spectroscopy and gas chromatography/mass spectrometry.
This work is dedicated to the 65th birthday of Prof. Dr. K. Pfeilsticker, Institut of Food Science, University Bonn (Germany). 相似文献
15.
Medium-chain fatty acid-rich glycerides by chemical and lipase-catalyzed polyester-monoester interchange reaction 总被引:4,自引:0,他引:4
Medium-chain triglycerides (MCT) that contain caprylic acid (C8:0) and capric acid (C10:0) have immense medicinal and nutritional importance. Coconut oil can be used as a starting raw material for the production
of MCT. The process, based on the interchange reaction between triglycerides and methyl esters of medium-chain fatty acids
by chemical catalyst (sodium methoxide) or lipase (Mucor miehei) catalyst, appears to be technically feasible. Coconut oils with 25–28.3% (w/w) and 22.1–25% (w/w) medium-chain fatty acids
have been obtained by chemical and lipase-catalyzed interchange reactions. Coconut olein has also been modified with C8:0 and C10:0 fatty acids, individually as well as with their mixtures, by chemical and lipase-catalyzed interchange reactions. Coconut
olein is a better raw material than coconut oil for production of mediumchain fatty acid-rich triglyceride products by both
chemical and lipase-catalyzed processes. 相似文献
16.
Douglas G. Hayes Robert Kleiman Bliss S. Phillips 《Journal of the American Oil Chemists' Society》1995,72(5):559-569
Members of the genusLesquerella, native to North America, have oils containing large amounts of hydroxy fatty acids and are under investigation as potential
new crops. The triglyceride structure of oils from twenty-fiveLesquerella species in the seed collection at our research center has been examined after being hydrolysis-catalyzed by reverse micellar-encapsulated
lipase and alcoholysis-catalyzed by immobilized lipase. These reactions, when coupled with supercritical-fluid chromatographic
analysis, provide a powerful, labor-saving method for oil triglyceride analysis. A comprehensive analysis of overall fatty
acid composition of these oils has been conducted as well.Lesquerella oils (along with oils from two other Brassicaceae:Physaria floribunda andHeliophilia amplexicaulis) have been grouped into five categories: densipolic acid-rich (Class I); auricolic acid-rich (Class II); lesquerolic acid-rich
(Class III); an oil containing a mixture of hydroxy acids (Class IV); and lesquerolic and erucic acid-rich (Class V). The
majority of Class I and II triglycerides contain one or two monoestolides at the 1- and 3-glycerol positions and a C18 polyunsaturated acyl group at the 2-position. Most Class III and IV oil triglycerides contain one or two hydroxy acids at
the 1- and 3-positions and C18 unsaturated acid at the 2-position. A few of the Class III oils have trace amounts of estolides. The Class V oil triglycerides
are mostly pentaacyl triglycerides and contain monestolide and small amounts of diestolide. Our triglyceride structure assignments
were supported by1H nuclear magnetic resonance data and mass balances. 相似文献
17.
J. Mustafa M. S. Ahmad Jr. A. Rauf S. M. Osman 《Journal of the American Oil Chemists' Society》1990,67(12):937-939
Branched-chain thioethers have been prepared from methyl 4-oxo-trans-2-hexadecenoate and 9,12-dioxo-trans-10-octadecenoic acid. The reagents involved in these preparations were mercaptoacetic and mercaptopropionic acids. The yields
of these thioethers are almost quantitative. 相似文献
18.
In situ esterifications of high-acidity rice bran oil with methanol and ethanol and with sulfuric acid as catalyst were investigated.
In the esterification with methanol, all free fatty acids (FFA) dissolved in methanol were interesterified within 15 min,
and it was possible to obtain nearly pure methyl esters. The amount of methyl esters obtained from a given rice bran was dependent
on the FFA content of the rice bran oil. In the esterification with ethanol, it was not possible to obtain pure esters as
in methanol esterification, because the solubilities of oil components in ethanol were much higher than those in methanol. 相似文献
19.
In order to measure exactly the trans-fatty acids content in food materials, a preparative group separation of cis- and trans-isomers of unsaturated fatty acid methyl esters (FAMEs) was achieved by an isocratic reversed-phase HPLC (RP-HPLC) method.
The trans-isomers of 16:1, 18:1, 18:2, 18:3, 20:1 and 22:1 FAMEs were readily separated from the corresponding cis-isomers by a COSMOSIL Cholester C18 column (4.6 mm I.D. × 250 mm, Nacalai Tesque) or a TSKgel ODS-100Z column (4.6 mm I.D. × 250 mm,
TOSOH), using acetonitrile as the mobile phase. This method was applied for determining the trans-18:1 fatty acid content in partially hydrogenated rapeseed oil. The methyl esters of cis- and trans-18:1 isomers of the oil were collected as two separate fractions by the developed RP-HPLC method. Each fraction was analyzed
by gas chromatography (GC) for both qualitative and quantitative information on its positional isomers. By a combination of
RP-HPLC and GC methods, a nearly complete separation of cis- and trans-18:1 positional isomers was achieved and the trans-18:1 fatty acid content was able to be evaluated more precisely than is possible by the direct GC method. The reproducibility
of cis- and trans-18:1 isomers fractionated by the RP-HPLC method was better than 98%. These results suggested that the preparative RP-HPLC
method developed in this study could be a powerful tool for trans-fatty acid analysis in edible oils and food products as an alternative to silver-ion chromatography. 相似文献
20.
We report here the synthesis of methyl 9,12-epoxyoctadecanoate (2-[7-methoxycarbonyl-heptyl]-5-hexanyl-tetrahydrofuran). Methyl
ricinoleate (methyl 12-hydroxy-9-cis-octadecenoate), isolated from castor oil methyl esters was isomerized with diphenyl disulfide as radical initiator under
ultraviolet radiation to give thetrans isomer, methyl ricinelaidate. The latter was cyclized by slow addition of 10% bromine solution in dichloromethane to give
methyl 10-bromo-9,12-epoxyoctadecanoate, which on hydrogenation with Pd/C catalyst gave the title compound, methyl 9,12-epoxyoctadecanoate. 相似文献