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1.
2.
Polyunsaturated fatty acid methyl esters of soybean oil (MeSBO) were selectively conjugated as a means of increasing the linolenate
selectivity of various homogeneous and heterogeneous hydrogenation catalysts. Kinetics of the conjugation reaction in various
solvents indicated that linolenate conjugated 5–8 times faster than linoleate. Selective conjugation of MeSBO with potassiumt-butoxide in dipolar solvents resulted in an increase in linolenate hydrogenation selectivity to 7–8 with Ni and Pd heterogeneous
catalysts, and to 7–10 with homogeneous and heterogeneous chromium carbonyl catalysts.Trans-unsaturation in the hydrogenated products was only 1–3% with the chromium carbonyl catalysts, in contrast to 30–39% with
the heterogeneous metal catalysts. Triglycerides were readily converted to partial glycerides andt-butyl esters with the potassiumt-butoxide reagent.
Presented at the AOCS North Central Section Symposium, March 1980. 相似文献
3.
Two samples of soybean oil hydrogenated with copper-containing catalysts at 170 and 200 C were analyzed for their natural
and isomeric fatty acids. Methyl esters of the hydrogenated oils were separated into saturates, monoenes, dienes and trienes
by countercurrent distribution between acetonitrile and pentane-hexane. Monoenes were further separated intocis- andtrans-isomers on a silver-saturated resin column. Double bond location in these fractions was determined by a microozonolysis-pyrolysis
technique. The diene fraction was separated with an argentation countercurrent distribution method, and linoleate was identified
by infrared, ozonolysis and alkaliisomerization data. The double bonds in thecis-monoenes were located in the 9-position almost exclusively. However, the double bonds in thetrans-monoene were quite scattered with 10- and 11-isomers predominating. About 86% to 92% of the dienes consisted of linoleate
as measured by alkali isomerization. Other isomers identified as minor components includecis,trans andtrans, trans conjugated dienes and dienes whose double bonds are separated by more than one methylene group.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
4.
5.
T. L. Mounts K. A. Warner G. R. List J. P. Fredrich S. Koritala 《Journal of the American Oil Chemists' Society》1978,55(3):345-349
Flavor and oxidative stabilities were studied by organoleptic evaluation and chemical analysis of three different samples
of soybean oil: unhydrogented (I); hydrogenated with nickel catalyst (II); and hydrogenated with copper-chromium catalyst
(III). Analyses for these oils were: I II III iodine Value 138 109 113 Linolenate, % 8.3 3.3 0.4 Each oil was deodorized with
the addition of either citric acid alone or citric acid plus BHA and BHT antioxidants. Addition of antioxidants did not improve
the flavor stabilities of the oils in accelerated storage tests but did improve the flavor stabilities of II and III in light
exposure tests. All three oils that received the same additive treatment had equivalent flavor stability in both accelerated
storage and light exposure tests. However, both hydrogenation and antioxidant treatment improved oxidative stability as measured
by the Active Oxygen Method. There was good correlation between flavor score and the logarithm of the peroxide value determined
at the time of tasting.
Presented at the AOCS Meeting, New York, May 1977. 相似文献
6.
The reaction of metallic salts in aqueous solution with sodium borohydride produces finely divided metals that are catalytically
active for hydrogenation. Salts of nickel, cobalt, palladium and platinum give active catalysts for the selective hydrogenation
of soybean oil. Iron and silver salts, when reduced with sodium borohydride, show no activity at 200C and atmospheric hydrogen
pressure. The cobalt catalyst produces the least amount of stearate. Incorporation of palladium, platinum, copper or chromium
up to 2% enhance the activity of the nickel catalyst. Copper and chromium salts, when reduced together, form catalysts that
hydrogenate linolenyl groups in soybean oil seven times more rapidly than linoleyl groups. No stearate formation is observed
with these binary catalysts.
Presented at the AOCS Meeting, Houston, April 1965.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
7.
K. J. Moulton Sr. S. Koritala K. Warner 《Journal of the American Oil Chemists' Society》1985,62(12):1698-1701
Soybean oil was partially hydrogenated in a continuous system with copper and nickel catalysts. The hydrogenated products
were evaluated for flavor and oxidative stability. Processing conditions were varied to produce oils of linolenate contents
between 0.4 and 2.7%, as follows: oil flow, 0.6–2.2 liters/hr; reaction temperature, 180–220 C; hydrogen pressure, 100–525
psig, and catalyst concentration, 0.5–1% copper catalyst or 0.1% nickel catalyst.Trans unsaturation varied from 8 to 20% with copper catalyst and from 15.0 to 27% with nickel catalyst. Linolenate selectivity
was 9 with copper catalyst and 2 with nickel catalyst. Flavor evaluation of finished oils containing 0.01% citric acid (CA),
appraised initially and after accelerated storage at 60 C, showed no significant difference between hydrogenated oils and
nonhydrogenated oil. However, peroxide values and oxidative stability showed that hydrogenated oils were more stable than
the unhydrogenated oil. CA+TBHQ (tertiary butylhydroquinone) significantly improved the oxidative stability of test oils over
oils with CA only, but flavor scores showed no improvement. Dimethylpolysiloxane (MS) had no effect on either flavor or oxidative
stability of the oils. 相似文献
8.
β-Eleostearate andtrans,trans-conjugated diene were reduced with deuterium in the presence of copper chromite. Considerable exchange of hydrogen atoms
of the starting material for deuterium atoms was observed. Conjugated double bond systems isomerized (positional and geometric)
extensively during hydrogenation. Isomerization and exchange reactions occurred at a faster rate than hydrogen addition reaction.
During early stages of the reaction, a large amount of the product formed contained no deuterium. Of the three possible mechanisms
of hydrogen addition toβ-eleostearate (1,2; 1,4 and 1,6), no one mechanism could account for all the products formed. Reduction oftrans-9,trans-11-octadecadienoate at a higher temperature and pressure (200 C, 500 psi) caused a minimum of exchange and isomerization
apparently due to sintering of the catalyst. Monoenes were formed fromtrans,trans-conjugated diene by both 1,2 and 1,4 addition. Methyl oleate was not reduced, but extensive isomerization occurred. Deuterium
was incorporated into isomeric monoenes. Mechanistic schemes are proposed to account for exchange, isomerization and hydrogen
addition.
Presented in part at the AOCS Meeting, New Orleans, April 1970. 相似文献
9.
10.
C. T. Hou M. O. Bagby R. D. Plattner S. Koritala 《Journal of the American Oil Chemists' Society》1991,68(2):99-101
Sixty-two cultures from the Agricultural Research Service (ARS) Culture Collection and 10 cultures isolated from soil and
water samples in Illinois were screened for their ability to convert agricultural oils to value-added industrial chemicals.
A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), was produced from oleic acid at a yield of greater than 60% by
bacterial strain PR3 which was isolated from a water sample in Morton, IL. To our knowledge, DOD has not been previously reported.
The optimum time, pH and temperature for the production of DOD were 2 days, 7.0, and 30°C, respectively. The production of
DOD is unique in that it involves hydroxylation at two positions and rearrangement of the double bond of the substrate molecule. 相似文献