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1.
Free Radical Additions to Unsaturated Fatty Acids Unsaturated fatty acids e.g. oleic acid are 1,2-dialkyl substituted alkenes with an electron-rich C,C-double bond. Elektrophilic free radicals can be added to the double bond to give functionalized and branched fatty acids. The electrophilic free radicals have been generated a) by oxidation of enolizable compounds by manganese (III) acetate prepared in situ by addition of potassium permanganate to catalytic amounts of manganese (II) acetate; b) with di-tert.-butylperoxide as initiator. Free radical addition of the radical to methyl oleate occurs to give an adduct radical which can be stabilized by hydrogen transfer or by oxidative elimination with copper (II) acetate. We have been able to add also alkanes e.g. cyclohexane to methyl oleate. A review of free radical additions to oleic acid is given. 相似文献
2.
T. A. Foglia P. A. Barr A. J. Malloy 《Journal of the American Oil Chemists' Society》1977,54(11):A858-A861
The use of phase transfer catalysis (PTC) as an aid in the oxidation of long chain olefins with aqueous potassium permanganate (KMnO4) in neutral and alkaline media and with aqueous ruthenium tetroxide (RuO4) is reported. The phase transfer catalysts (PTCT) were either quaternary ammonium halides or crown ethers. The long chain olefins studied were 1-pentadecene, 9-octadecene, and methyl oleate. PTC not only increases the rate of these reactions but also gives good yields of reaction products. For example,cis-9-octadecene in methylene chloride reacted with aqueous KMnO4 to give either dihydroxyoctadecane (80%) or pelargonic, acid (80%) depending upon pH, when tetrabutylammonium bromide was used as the PTCT. When RuO4 in conjunction with a PTCT was used as the oxidant, a quantitative yield of myristic acid was obtained from 1-pentadecene. The RuO4 oxidant was conveniently regenerated in situ from RuO2 and sodium hypochlorite. This regeneration is facilitated with a PTCT. 相似文献
3.
N. A. Khan W. E. Tolberg D. H. Wheeler W. O. Lundberg 《Journal of the American Oil Chemists' Society》1954,31(11):460-466
- It has been confirmed that the principal products formed in the oxidation of methyl oleate by oxygen under a variety of conditions are predominantlytrans hydroperoxides. However no inversion of the double bond occurs in unoxidized oleate. Hence the conversion ofcis totrans double bonds and peroxide formation occur together in the same molecules.
- The autoxidation of methyl linoleate at low temperature yields predominantlycis,trans conjugated hydroperoxides. Autoxidation at 25°C., oxidation catalyzed by visible light, or ultraviolet light and copper soap catalyzed oxidation at temperatures appreciably above 0°C., lead to the formation primarily oftrans,trans conjugated hydroperoxides. The inversion of the second double bond in this case appears to be independent of the peroxide-forming reactions.
- The photochlorophyll oxidation of methyl linoleate leads to the formation of some unconjugated hydroperoxides, some of which containtrans double bonds.
- Under all of the conditions employed in the present investigation, the oxidation of methyl oleate and linoleate led primarily to the formation of monomeric peroxides which retained most of the unsaturation of the parent compound.
4.
5.
E. N. Frankel C. D. Evans J. C. Cowan 《Journal of the American Oil Chemists' Society》1960,37(9):418-424
Summary When autoxidized fatty esters and purified fatty hydroperoxides were decomposed in the absence of oxygen at 210°C., the principal
reaction was dimerization of the fatty acid chains with elimination of the hydroperoxide groups. Dimers isolated by molecular
distillation (60 to 90% of the polymer) have approximately 1 mole hydroxyl, 0.5 mole carbonyl, and two double bonds per mole
of dimer. Diene conjugation in the dimers from polyunsaturated fat hydroperoxides varied from 10 to 23%. The infrared spectra
of the dimers were similar to those of the original fatty esters except for one striking band at 2.9 μ, which is attributed
to the secondary hydroxyl group. Thecis-trans diene in the polyunsaturated hydroperoxides was isomerized to thetrans-trans configuration on dimerization. The methyl oleate hydroperoxide dimer showed only absorption for isolatedtrans double bond. The dimer was not split either by catalytic hydrogenation or by hydrogen iodide, indicating a carbon-carbon
bond between the monomer units. On oxidation with permanganate and periodate, the dimeric acids behaved like a monounsaturated
mixture containing double bonds in the C6, C7, C8, C9, and C10 positions in the oleate dimer and in the C8, C9, and C10 positions in the safflower ester dimer. Although the dimers showed no peroxidic oxygen iodometrically with potassium iodide,
a reduction occurred with hydriodic acid that may indicate the presence of intramolecular peroxide groups and/or allylic alcohol
or carbonyl groups. Bromination with N-bromosuc-cinimide and dehydrobromination with N,N-dimethyl aniline produced no aromatization.
Subsequent oxidation of the dehydrobrominated dimer yielded 2.6% residue, which was not aromatic. This evidence indicates
that the dimer does not have a six-membered cyclic structure. Dimerization of the hydroperoxides is suggested as occurring
through alkyl or alkoxy hydroperoxide radicals to give carbon-carbon linked fatty acid dimers and some higher polymeric units.
Presented at 33rd fall meeting, American Oil Chemists’ Society, Los Angeles, Calif., Sept. 28–30, 1959.
This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department
of Agriculture. 相似文献
6.
J. T. Knegtel C. Boelhouwer M. Tels H. I. Waterman 《Journal of the American Oil Chemists' Society》1957,34(7):336-337
Summary The displacement of the double bond of methyl oleate during hydrogenation with a nickel-kieselguhr catalyst at 180°C. was
investigated, particularly with respect to the analysis of dicarboxylic acids, obtained either by oxidation of the reaction
products with KMnO4 in acetic acid or by means of ozone.
In the oxidation experiments with KMnO4 a considerable degradation of lower molecular dicarboxylic acids occurs that makes a quantitative analysis of the isomerization
phenomena uncertain.
According to the ozonization experiments an equal migration of the double bond in both directions, toward and opposite the
ester group, takes place. 相似文献
7.
P. Van Der Plank 《Journal of the American Oil Chemists' Society》1972,49(5):327-332
Methyl oleate was hydrogenated at temperatures varying from 50–175 C over three nickel-silica catalysts of different pore-size
distribution. Methyl elaidate was reduced over one of these catalysts at temperatures between 75–150 C. From the detailed
double bond distributions information was obtained on transport phenomena in the pores of the catalyst. It was established
that the migration of the double bond in methyl oleate proceeds with a stepwise mechanism, and evidence was obtained that
the double bond in methyl elaidate migrates significantly faster than that in methyl oleate, while the rate of hydrogenation
of these esters was equal. Thetrans-cis ratio of the geometrical isomers which are formed by double bond migration varies strongly during hydrogenation. 相似文献
8.
Frank C. Naughton 《Journal of the American Oil Chemists' Society》1974,51(3):65-71
The presence of a hydroxyl group, in addition to an olefinic linkage, in the predominating fatty acid of castor oil gives
this vegetable oil many unique and interesting properties. Castor oil consists largely of glycerides of ricinoleic acid or
12-hydroxy octadecenoic acid. The chemical reactions of castor oil, undecylenic acid, 12-hydroxylstearic acid, sebacic acid,
and nylon 11, depict the uniqueness of this agricultural oil. By dehydration, castor oil is converted to a conjugated acid
oil similar to tung or oiticica oil. The catalytic dehydration results in the formation of a new double bond in the fatty
acid chain. The dehydrated castor oil imparts good flexibility, rapid dry, excellent color retention, and water resistance
to protective coatings. The pyrolysis of castor oil cleaves the molecule to produce undecylenic acid and heptaldehyde. The
pyrolysis of the methyl ester at 450–550 C results in the formation of methyl 10-undecylenate. Hydrolysis of the methyl ester
gives 10-undecylenic acid. Hydrogen bromide is added to form 11-bromo undecanoic, which is ammoniated and condensed to form
a nylon polymer. When castor oil is added slowly to an 80% caustic solution, the sodium ricinoleate formed splits to form
sodium sebacate and capryl alcohol. Sebacic acid is condensed with hexamethylene diamine to form nylon 6,10. The commercial
application of castor oil derivatives in urethanes, starch gel modifiers, medium chain triglycerides, and thixotropic additives
is reviewed briefly.
One of 12 papers presented in the symposium “Novel Uses of Agricultural Oils” at the AOCS Spring Meeting, New Orleans, April
1973. 相似文献
9.
George J. Piazza Thomas A. Foglia Alberto Nuñez 《Journal of the American Oil Chemists' Society》2001,78(6):589-592
Peroxygenase is a plant enzyme that catalyzes the oxidation of a double bond to an epoxide in a stereospecific and enantiofacially
selective manner. A microsomal fraction containing peroxygenase was prepared from oat (Avena sativa) seeds and the enzyme immobilized onto a hydrophobic membrane. The enzymatic activity of the immobilized preparation was
assayed in 1 h by measuring epoxidation of sodium oleate (5 mg) in buffer-surfactant mixtures. The pH optimum of the reaction
was 7.5 when t-butyl hydroperoxide was the oxidant and 5.5 when hydrogen peroxide was the oxidant. With t-butyl hydroperoxide as oxidant the immobilized enzyme showed increasing activity to 65°C. The temperature profile with hydrogen
peroxide was flatter, although activity was also retained to 65°C. In 1 h reactions at 25°C at their respective optimal pH
values, t-butyl hydroperoxide and hydrogen peroxide promoted epoxide formation at the same rate. Larger-scale reactions were conducted
using a 20-fold increase in sodium oleate (to 100 mg). Reaction time was lengthened to 24 h. At optimized levels of t-butyl hydroperoxide 80% conversion to epoxide was achieved. With hydrogen peroxide only a 33% yield of epoxide was obtained,
which indicates that hydrogen peroxide may deactivate peroxygenase. 相似文献
10.
The reactions of ruthenium VIII tetroxide (RuO4) and the ruthenium VII and VI oxyanions, perruthenate (RuO4
−) and ruthenate (RuO4
=) with hydroxy substituted and unsaturated fatty acids have been studied. At a 1:1 molar ratio, ruthenium tetroxide (RuO4) and both oxyanions (RuO4
− and RuO4
=) oxidized 12-hydroxystearic acid to 12-ketostearic acid. With 9, 10-dihydroxystearic acid, the type of oxidation products
obtained depended on the amount of ruthenium oxidant used. At high ratios of oxidant to substrate, cleavage to pelargonic
and azelaic acids occurred whereas at lower ratios, partial oxidation to diketo and acyloin derivatives predominated. The
oxidation of oleic acid with excess ruthenium tetroxide (RuO4) or perruthenate anion (RuO4
−) gave the cleavage products pelargonic and azelaic acid through the intermediate formation of dihydroxy and diketo intermediates.
Ruthenate anion (RuO4
=) did not react with the double bond of oleic acid.
Agricultural Research Service, U.S. Department of Agriculture. 相似文献
11.
J. G. Keppler J. A. Schols W. H. Feenstra P. W. Meijboom 《Journal of the American Oil Chemists' Society》1965,42(3):246-249
The characteristic hardening flavor which develops in hardened linseed and soybean oils during storage has been coned from
hardened linseed oil by stripping with nitrogen. After separating the volatile substances by adsorption chromatography on
silica, the fraction containing the hardening flavor has been converted into 2,4-dinitrophenylhydrazones (DNPHs) and separated
by means of partition chromatography. On regeneration of the fractions of DNPSs obtained, the characteristic hardening flavor
was observed in one specific band. Both by hydrogenation and by oxidation of the free carbonyl the carrier of the flavor was
found to be an unsaturated aldehyde; however, not of the α-β unsaturated type. Further separation of the regenerated carbonyls
by means of gas-liquid chromatography (GLC) points to a C9-aldehyde. After synthesis of the 4-,5- and 6-cis- andtrans-nonenals, comparison made it probable that the carrier of the hardening flavor is a mixture of 6-cis and 6-trans-nonenal, the latter of which has the greatest share in the hardening flavor.
In order to confirm the location of the double bond in the carrier of the hardening flavor a recent isolation technique was
applied. The volatile substances from hardened linseed oil were first separated via GLC. After conversion of the carbonyls
in question into their DNPHs, the latter have been separated by means of thin-layer chromatography (TLC). By means of IR-analysis
and oxidation with osmium tetroxide of the pure derivative, the principal carrier of the hardening flavor has been identified
as 6-trans-nonenal. 相似文献
12.
Unsaturated fatty acids such as oleic acid are 1,2-dialkyl substituted alkenes, which can be functionalized by free radical addition to the C, C double bond. We have been able to add enolizable compounds, e.g. acetone, acetic acid and malonic acid to methyl oleate mediated by manganese(III)acetate. Azide radicals, generated by manganese(III)acetate-oxidation of sodium azide, have also been added to methyl oleate. Perfluoralkyl iodides have been added via perfluoroalkyl radicals to methyl 10-undecenoate and methyl oleate to form the corresponding addition products. Reduction of the iodides by tributyltin hydride and saponification leads to interesting partially fluorinated fatty acids. 相似文献
13.
Acetone powder from germinating rape (Brassica napus L.) seedlings exhibits essentially similar activity in lipolysis of triacylglycerols as the corresponding seedling homogenates.
Acetone powder from rape seedlings catalyzes the esterification of a fatty acid, such as oleic acid, withn-butanol or a long-chain alcohol, such as oleyl alcohol. Furthermore, the acetone powder catalyzes alcoholysis of a methyl
ester, such as methyl oleate withn-butanol or oleyl alcohol, and acidolysis of methyl oleate with a fatty acid, such as erucic acid. However, triacylglycerols
are not accepted as substrates fro interesterification reactions. In esterification of fatty acids withn-butanol, catalyzed by the acetone powder from rape seedlings, fatty acids having an olefinic bond next to the carboxyl group
as acis-6 double bond, e.g., γ-linolenic, gorlic and petroselinic acids, or those having acis-4 double bond, e.g., docosahexaenoic acid, are strongly discriminated against as substrates. Such substrate selectivities
can be utilized for the enrichment of definite fatty acids from mixtures, derived from naturally occurring oils,via kinetic resolution.
Part of the doctoral thesis of Iván Jachmanián to be submitted to Facultad de Química. Universidad de la República, Montevideo,
Uruguay. 相似文献
14.
15.
G. E. M. Moussa S. O. Abdalla 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1970,20(8):256-260
The oxidation of 1,1,2-triphenylbut-1-ene by chromium trioxide in acetic anhydride gives 1,2-epoxy-1,1,2-triphenylbutane with fission products and 1,1,2-triphenylacetylethylene. Cis- and trans-1-p-chlorophenyl-1,2-diphenylprop-1-ene yield crystalline epoxides in satisfactory yields under similar conditions. The epoxides are stable towards aqueous sulphuric acid. 1,1,2-Triphenylethylene, 1,1-di-(p-chlorophenyl)-2-phenylethylene and 1,1-di-(p-bromophenyl)-2-phenylethylene are similarly oxidised but the epoxides are hydrated to the glycols by the action of aqueous sulphuric acid. Chromic acid in aqueous sulphuric acid brings about oxidative fission of the double bond without any rearrangement. 相似文献
16.
Robert A. Grimm 《Journal of the American Oil Chemists' Society》1969,46(11):611-614
Unsaturated fatty materials, such as ethyl oleate and oleonitrile, are found to react with carbon monoxide, hydrogen and aniline
at 150 C to give N-monoalkylanilines. The alkyl group is derived from the unsaturated fatty material plus the group H-CH2 added across the double bond. Similarly 1-decene, in a rapid reaction, gives N,N-di-n-undecylaniline and N-undecylaniline as major and minor products respectively. 1,2,3-Tris-(triphenylphosphine)trichlorohodium
is an excellent catalyst for this reaction.
Presented at the AOCS Meeting, San Francisco, April 1969. 相似文献
17.
18.
19.
The effect of excess lauric and oleic acids on the conductivity and on the pH of 0.2–0.02N potassium laurate and 0.1–0.01N sodium oleate systems was observed. The decrease in the specific conductivity corresponded with the formation of the acid soaps, 2KL·HL, KL·HL, 2NaOl·HOl, NaOl·HOl, and the mixed soaps 2KL·HOl and 2NaOl·HL. The mixed soaps resemble the oleates in appearance. All of these systems, even with 100 or 150 moles per cent excess acid, were slightly alkaline. 相似文献
20.
Photosensitized oxidation of unsaturated fatty acid methyl ester was carried out using methylene blue as a sensitizer. Oxidation
products, monohydro-peroxides, were identified as trimethylsilyl derivatives. Methyl oleate gave the 9- and 10-isomers; methyl
linoleate, the 9-, 10-, 12-, and 13-isomers; and methyl linolenate, the 9-, 10-, 12-, 13-, 15-, and 16-isomers, respectively.
The double bond to which the hydroperoxide group attached was shifted to the adjacent position in each isomer. Thus, both
conjugated and nonconjugated isomers were present in methyl linoleate monohydroperoxides and methyl linolenate monohydroperoxides.
By the inhibition experiment, it was ascertained that the above reaction proceeded via singlet oxygen. The relative rates
of methyl oleate, methyl linoleate, and methyl linolenate were 1.0∶1.7∶2.3, respectively. These results obtained from the
methyl esters were applied to the photosensitized oxidation of triglycerides purified from vegetable oils, and the reaction
mechanism on triglycerides was proposed. 相似文献