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1.
J. -L. Sebedio M. F. Langman C. A. Eaton R. G. Ackman 《Journal of the American Oil Chemists' Society》1981,58(1):41-48
During hydrogenation of a refined herring(Clupea harengus) oil iodine value (IV) 119, on a commercial nickel catalyst, samples were collected at IV 108, 101, 88 and 79. In the early
stages of the process, IV 119 to IV 101, the positional and geometrical isomerization of the long chain monoenoic fatty acids
(20:1 and 22:1) was hindered by the stronger absorption on the catalyst surface of the polyenes with 4, 5 and 6 double bonds.
Consequently at IV 101, 70% of these polyenes had been converted to dienoic and trienoic fatty acids, but only 3-4%trans 20:1 and 22:1 accumulated. As the hydrogenation proceeded, IV 101 to IV 79, the originaleis 20:1 and 22:1 isomers (mainly Δ11 with some ΔA9 and Δ13) decreased and new positional and geometrical isomers (both cis andtrans in positions Δ6 to Δ15) were formed. The majortrans isomers were Δ11 accompanied by important proportions of Δ10 and Δ12. At IV 79, moretrans 20:1 (ca. 36%) thantrans 22:1 (ca. 29%) was detected. Monoethylenic fatty acids newly formed from polyethylenic fatty acids made only minor contributions
to the total 20:1 and 22:1 at these levels of hydrogenation, but a “memory effect” which skews the proportions of minorcis andtrans isomers can be attributed to the proportions of minorcis 22:1 isomers (Δ9, Δ13 and Δ15) orginally present.
Presented in part at AOCS Annual Conference, San Francisco, May 1979. 相似文献
2.
Sambasi Varao Koritala 《Journal of the American Oil Chemists' Society》1973,50(4):110-111
Alkali-conjugated linoleate (cis-9,trans-11- andtrans-10,cis-12-octadecadienoate) was hydrogenated with nickel, palladium and platinum catalysts. Thetrans andcis monoenes formed during reduction were isolated, and their double bond distribution was determined by reductive ozonolysis
and gas liquid chromatography. About 44–69% of the monoenes were composed of δ10 and δ11
trans monoene isomers, whereas the δ9 and δ12
cis monoenes amounted to 20–26%. With nickel catalyst, composition of monoene isomers remained the same, even when the hydrogenation
temperature was increased. The monoene isomer profiles between nickel and palladium catalysts were indistinguishable. Isomerization
of monoenes with platinum catalyst was suppressed at 80 psi. The position of the double bonds in unreacted conjugated diene
was always retained, except with nickel at both temperatures and with platinum at 150 C when a slight migration occurred.
Geometrical isomerization totrans,trans-conjugated diene was observed in the unreacted diene with nickel (ca. 15% of diene) at both 100 C and 195 C, and with platinum
(ca. 7% of diene) at 150 C.
ARS, USDA. 相似文献
3.
K. D. Mukherjee Irmgard Kiewitt M. Kiewitt 《Journal of the American Oil Chemists' Society》1975,52(8):282-288
Hydrogenation characteristics of a wide variety of stationary catalysts were studied with an aim to explore their possible use in the continuous hydrogenation of fats. Refined soybean oil was hydrogenated continuously in a vertical flow-through reactor over a fixed bed of catalyst. Catalysts investigated were pelleted products containing Raney nickel, reduced nickel, reduced palladium, and copper chromite, as well as granulated alloys of the Raney type, such as Ni-Al, Cu-Al, Pd-Al, and Cu-Cr-Al, which were activated with alkali. These catalysts offered a wide choice of activity, selectivity, and ability to form geometrical isomers. Pelleted copper chromite and granular Raney copper-chromium were found to be highly selective toward the linolenate moiety of soybean oil, whereas pelleted palladium on carrier, as well as granular Raney nickel, Raney copper, and Raney palladium, though moderately selective, exhibited very high activity even at relatively low temperatures. A unique feature of most of the stationary catalysts was the remarkably high rate of hydrogenation. With most catalysts, the iodine value of soybean oil was reduced by 40–60 units within a reaction period of 2–4 min. The hydrogenated fat was practically free of catalyst particles. 相似文献
4.
Hydrogenation of milk fat with palladium and nickel as catalysts was studied at various temperatures, pressures, and concentrations
of catalyst. Samples were removed from the laboratory hydrogenator at intervals during the reaction, and changes in refractive
index, iodine value, Wiley mp, and percentages of fatty acids andtrans-isomers were determined. Palladium was several times more active as a catalyst than nickel. Milk fat with an iodine value
of 35 and mp of 34 C was hydrogenated with 0.05% palladium to an iodine value of 6 and a mp of 46 C in 30 min at 66 C and
53 psi of hydrogen. Kinetic data for each catalyst yielded two slopes, indicating that a change in reaction rate occurred. 相似文献
5.
N. Hsu L. L. Diosady W. F. Graydon L. J. Rubin 《Journal of the American Oil Chemists' Society》1986,63(8):1036-1042
The hydrogenation of canola oil was studied using palladium black as a potential catalyst for producing partially hydrogenated fats with lowtrans-isomer content. Pressure (150\s-750 psig) appeared to have the largest effect ontrans-isomer formation. At 750 psig, 90 C and 560 ppm metal concentration, a maximum of 18.7%trans isomers was obtained at IV 53. A nickel catalyst produces about 50%rans isomers at the same IV. For palladium black, the linolenate and linoleate selectivities were 1.2 and 2.7, respectively. The maximum level oftrans isomers observed ranged from 18.7% to 42.8% (150 psig). Temperature (30\s-90 C) and catalyst concentration (80\s-560 ppm) affected the reaction rate with little effect ontrans-isomer formation and selectivities. At 250 psig and 50 C, supported palladium (5% Pd/C) appeared to be twice as active as palladium black. At 560 ppm Pd, 5% Pd/C produced 30.2%trans (IV 67.5), versus 19.0%trans for palladium black (IV 68.9). Respective linoleate selectivities were 15 and 6.6, while linolenate selectivities were approximately unity. Analysis of the oil samples by neutron activation showedapproximately a 1 ppm, Pdresidue after filtration. 相似文献
6.
We have compared a nickel with a copper catalyst in the formation of some geometrical and positional isomers during the partial
hydrogenation of trilinolein. The copper catalyst was found to produce fewer diene isomers than the nickel catalyst at a comparable
iodine value. The copper catalyst produced more monoene isomers however, than did the nickel, particularlytrans monoenes. The distribution of the monoene isomers appeared to obey an equilibrium relationship with each other, independent
of both iodine value and reaction conditions. We have presented additional evidence to postulate that copper catalysts hydrogenate
polyenoic acids by first conjugating the acids. The selectivity of copper catalysts for triene over diene is probably due
to the greater ease of conjugation of the triene. 相似文献
7.
Methylcis-9,cis-15-octadecadienoate was partially deuterated with nickel catalyst, and the product was separated into saturate, monoene and
diene fractions. Monoenes were separated intotrans andcis fractions, and dienes intotrans,trans, cis,trans andcis,cis fractions. Monoene isomers with double bonds at the 9 and 15 positions predominated in bothcis- andtrans-monoene fractions. Considerable amounts of isomers with double bonds situated on either side of the original 9 and 15 positions
were found in thetrans-monoene fraction. Diene was extensively isomerized to positional and geometrical isomers, and deuterium was incorporated
into these isomers. Double bond migration was greatest intrans,trans-dienes and smallest incis,cis-dienes. The amount of deuterium in the dienes was proportional to the extent of isomerization experienced by the dienes.
ARS, USDA. 相似文献
8.
M. M. Mossoba R. E. McDonald J. A. G. Roach D. D. Fingerhut M. P. Yurawecz N. Sehat 《Journal of the American Oil Chemists' Society》1997,74(2):125-130
The trans octadecenoic acid methyl ester isomers were obtained from a partially hydrogenated soybean oil sample and isolated by silver-ion
high-performance liquid chromatography. The double bond configuration was confirmed to be trans by using gas chromatography-direct deposition-Fourier transform infrared spectroscopy. The double bond positions for nine
individual trans octadecenoic acid positional isomers were confirmed by gas chromatography-electron ionization mass spectrometry after derivatization
to 2-alkenyl-4,4-dimethyloxazoline. These nine trans positional isomers were resolved on either one of the two polar 100% cyanopropylpolysiloxane 100-m capillary columns, SP
2560 and Cp-Sil 88, at an isothermal temperature of 140°C. These nine isomers were confirmed to have double bonds at carbons
C-8 through C-16. The pair of trans octadecenoic acid positional isomers with double bonds at C-13 and C-14 are reported for the first time to be resolved by
gas chromatography.
This work was presented in part at the 87th American Oil Chemists’ Society Annual Meeting in Indianapolis, IN, April 28–May
1, 1996. 相似文献
9.
Palladium supported on alumina was used to hydrogenate soybean and canola oil. Previous literature reports indicated that
palladium forms moretrans isomers than nickel. At 750 psig, 50 ppm palladium, and at 70 C, only 9.4%trans were formed when canola oil was hydrogenated to IV 74. In general, high pressure and low temperature favored lowtrans formation with no appreciable loss in catalyst activity. The effect of pressure, temperature and catalyst concentration on
reaction rate,trans formation and selectivity is presented. A survey of various catalyst supports is discussed. Apparent activation energies
of 6.3 to 8.9 kcal/mol were obtained; they are in good agreement with values reported in the literature. 相似文献
10.
E. A. Emken E. N. Frankel R. O. Butterfield 《Journal of the American Oil Chemists' Society》1966,43(1):14-18
Hydrogenation of linseed and soybean methyl esters was achieved at 100–180C, 100–1000 psi H2 and 0.05–0.25 moles catalyst per mole of ester. The relative activity of metal acetylacetonates in decreasing order was:
nickel (III), cobalt (III), copper (II) and iron (III). Reduction occurred readily in methanol solution but only slowly in
dimethylformamide and acetic acid. No reduction occurred in the absence of solvents. Soybean oil was also hydrogenated rapidly
with nickel (III) acetylacetonate in methanol, but in this system the triglycerides were converted to methyl esters. Nickel
(III) acetylacetonate was the most selective catalyst toward linolenate hydrogenation. Methyl linoleate and linolenate hydrogenated
with nickel(III) acetylacetonate were fractionated into monoenes, dienes and trienes. Thecis monoenes separated in 62 to 68% yield had double bonds in the original position. The remainingtrans monoenes had extensively scattered unsaturation. The dienes and trienes showed no conjugation, but some of the double bonds
in the dienes were not conjugatable with alkali. Little stearate was formed.
Presented at AOCS meeting in Chicago, 1964
No. Util. Res. and Dev. Div. ARS, USDA 相似文献
11.
Sambasivarao Koritala C. R. Scholfield 《Journal of the American Oil Chemists' Society》1970,47(8):262-265
Methyl linolenate was hydrogenated with 10% copper chromite catalyst at 150 C and atmospheric hydrogen pressure. The product
was separated into monoene, diene and triene fractions by countercurrent distribution. These fractions were further separated
into various geometrical isomers. The double bond location in the various fractions was determined by reductive ozonolysis.
Double bonds in bothcis andtrans monoene fractions, as well as incis,trans andtrans,trans conjugated dienes, were extensively isomerized. A monoene containing vinylic unsaturation was one of the major products.
The nonconjugated dienes were mostly dienes whose double bonds were widely separated. Results are explained on the basis of
conjugation of the double bonds in linolenate followed by hydrogen addition.
Presented in part at the symposium “Hydrogenation Process,” Division of Industrial Engineering Chemistry, 157th American Chemical
Society Meeting, Minneapolis, April 1968.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
12.
Karsten Ilsemann Kumar D. Mukherjee 《Journal of the American Oil Chemists' Society》1978,55(12):892-896
Continuous hydrogenation of fats and fatty acids using suspended catalysts was studied in a vertical flow reactor packed with
Raschig rings. A short time of reactive contact of the fat or the fatty acid with the catalyst and hydrogen is the unique
feature of this system. A nickel catalyst used in the hydrogenation of soybean oil gave a reduction of 40-50 iodine value
units per min, small amounts oftrans-isorners (10-20%), large proportions of linoleate in unreduced octadecadienoyl moieties (70-80%), and nonselective reduction
of polyunsaturated acyl moieties (linoleate selectivity ratio 1-3). Another nickel catalyst, used in the hydrogenation of
tallow fatty acids, also gave a reduction of 40-50 iodine value units per min and nonselective reduction of polyunsaturated
fatty acids. A copper chromite catalyst used in the hydrogenation of soybean oil gave a reduction of 10-15 iodine value units
per min, low levels oftrans- isomers (10-15%), and selective reduction of linolenoyl moieties (linolenate selectivity ratio 4-6). Composition of positional
isomers of cis- andtrans-octadecenoyl moieties in partially hydrogenated products obtained both with nickel and copper chromite catalysts reveals
that essentially the same mechanisms of isomerization are involved in continuous hydrogenation at short time of reactive contact
as in batch hydrogenation.
1The terms “linoloyl” and “linolenoyl” are used throughout to designate9-cis, 12-cis-octadecadienoyl and 9-cis, 12-cis, 15-cis- octadecatrienoyl groups, respectively. 相似文献
13.
M. H. Chahine E. R. Cousins R. O. Feuge 《Journal of the American Oil Chemists' Society》1958,35(8):396-401
Summary A commercial cottonseed oil was hydrogenated under nonselective, normal, and selective conditions. The operating variables
used were within the ranges of those ordinarily found in large-scale operations. For each run samples were withdrawn at iodine
values of approximately 75, 62, and 48; and these samples were analyzed for the position of the donble bonds, content oftrans isomers, and content of linoleins.
Double bonds were found in the 6 through 14 positions of the monounsaturated fatty acid groups resulting from the hydrogenations.
On the basis of the percentage distribution of the double bonds, there appeared to be no marked tendency for the linoleoyl
group to form 9- or 12-isomers of the oleoyl group. In the early stages of the selective hydrogenation the rate at which double
bonds shifted from the 9-position was greater than the rate at which double bonds were hydrogenated.
The conditions of hydrogenation did not have a marked effect on the distribution of the double bonds at iodine values of about
62 and 48.
The conditions of hydrogenation did have a marked effect on the percentage oftrans bonds. At an iodine value of approximately 75 the content oftrans bonds, expressed as weight percentage of trielaidin, was 9.4 for the nonselective hydrogenation and 27.3 for the selective
hydrogenation while at an iodine value of approximately 48 these values increased to 21.6 and 37.7, respectively.
Presented at the 48th Annual Meeting. American Oil Chemists' Society, New Orleans, La., April 29–May 1, 1957.
One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S.
Department of Agriculture. 相似文献
14.
The level oftrans-18∶1 isomers in several isolated lipid classes of human liver, heart, red blood cells and plasma was determined. Phospholipids
contained substantially fewertrans-18∶1 isomers than triglycerides. The double bond distribution of thecis andtrans octadecenoate fraction of triglycerides and phosphatidylcholines from human liver and heart was determined. Whereas the double
bond distribution of the triglycerides correlated closely with the pattern found in dietary hydrogenated vegetable oils, the
phosphatidylcholine fraction showed evidence of selective incorporation or metabolism of specifictrans positional isomers. In general, isomers with double bonds near the methyl terminus were present at levels higher than expected
from their relative abundance in the diet. Refinements in methodology needed to analyze octadecenoate double bond configuration
and location in human tissues are presented. 相似文献
15.
Summary Infrared and ultraviolet studies have shown that the three geometrically isomeric types of conjugated linoleates (cis, cis; cis, trans; andtrans, trans) are readily equilibrated by dilute iodine and light. Infrared shows that the equilibrium is at 32%cis, trans and 64%trans, trans isomer. Probably no more than 5–10%, if any,cis, cis isomer exists at equilibrium. The equilibrated mixture can be used to determine total conjugation in mixtures of conjugated
geometric isomers by either infrared or ultraviolet absorption.
Paper No. 206 Journal Series, General Mills Research. 相似文献
16.
Summary Thecis-trans and positional configuration of α-and β-kamlolenic acids have been investigated. Infrared data of the two isomers, their
acetyl derivatives and maleic anhydride adducts, and the permanganate oxidation products of the addition compounds, together
with the selective epoxidation of the exocyclic double bond of the maleinated derivatives, have been used to confirm the structure
of the three conjugated double bonds in α-kamlolenic acid ascis-9-trans 11-trans 13. and β-kamlolenic acid astrans 9-trans 11-trans 13. 相似文献
17.
Summary It was found that during the hydrogenation of octadecenoic acids, migration of the double bonds takes place equally in each
direction. The positional isomers that are formed are composed of the 1∶2 equilibrium mixture ofcis andtrans. A partial hydrogenation-dehydrogenation theory may be applied to explain the simultaneous formation of both positional and
geometrical isomers.
Presented at the annual spring meeting of the American Oil Chemists' Society, San Antonio, Tex., Apr. 12–14, 1954. 相似文献
18.
Lipase (EC 3.1.1.3) from the microorganismGeotrichum candidum preferentially hydrolyzescis-9 18∶1 andcis,cis-9,12 18∶2 from triacylglycerols, largely ignoring all other positional isomers ofcis 18∶1 as well astrans-9 18∶1. To obtain additional information about the specificity of the enzyme, two triacylglycerols were prepared and utilized
as substrates. The lipase hydrolyzed 85%cis,cis-9,12 18∶2 and 15%trans,trans-9,12 18∶2 from the triacylglycerol, containing ca. 50% of each acid. From the triacylglycerol containing 46.3%cis,trans-9,12 18∶2 and 53.7%trans,cis-9,12 18∶2, 44.8 and 55.2% of the two acids were hydrolyzed. Therefore the enzyme discriminated against thetrans,trans isomer but not between thecis,trans andtrans,cis isomers.
Scientific contribution No. 535, Agricultural Experiment Station, University of Connecticut.
ARS, USDA. 相似文献
19.
Michael A. Jackson Gary R. List Debra Palmquist 《Journal of the American Oil Chemists' Society》2008,85(5):481-486
Low trans fatty acid basestocks suitable for blending with liquid oils to make spreads and shortenings are prepared by using a two-step
hydrogenation process. The first step uses a nickel catalyst to hydrogenate soybean, canola, high-oleic sunflower, and high-oleic
safflower oils to a predetermined iodine value. At this point in the reaction, the second step commenced. Addition of a platinum
catalyst at 80 °C and 73 psi hydrogen pressure allowed for hydrogenation to proceed to iodine values of 40–50. These products
had 11–18% trans fatty acid content. These were then blended with soybean oil (5–50% basestock) to give products with bulk properties similar
to commercial spreads and shortenings but with about one third the levels of trans fat.
Names are necessary to report factually an available data: the USDA neither guarantees nor warrants the standard of the product,
and the use of the name USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
20.
W. E. Tolberg R. F. Paschke D. H. Wheeler 《Journal of the American Oil Chemists' Society》1961,38(2):102-104
Methyl esters ofbeta eleostearic,alpha eleostearic, and punicic acids have been isomerized with iodine and light to the same equilibrium mixture of 64%beta, 33%alpha, and 2.6% punicate structures. The course of isomerization is in agreement with the following structures:trans, trans, trans forbeta; cis, trans, trans foralpha; andcis, trans, cis for punicate, in agreement with structures provenvia synthesis by Crombie and Jackson. There is some theoretical and experimental evidence that the center double bond of this
type of conjugated triene isomerizes less readily than the outer double bonds.
Paper No. 253, Journal Series, General Mills Inc., Central Research. 相似文献