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1.
John C. Bailar Jr. Hiroshi Itatani 《Journal of the American Oil Chemists' Society》1966,43(6):337-341
Mixtures of platinum complexes and tin(II) chloride are effective homogeneous catalysts for the hydrogenation of soybean oil
methyl ester, reducing it to the monoene stage only. Hydrogenation and isomerization reactions have been examined under various
conditions, using a solvent consisting of 60% benzene and 40% methanol.
The extent of hydrogenation depends upon the temperature (90C>60C>30C) but not upon the pressure (1075 psi as compared with
525 psi). It almost stops after 3 hr, although one double bond remains in the molecule.
After hydrogenation with a catalyst consisting of a mixture of dichloro-bis-triphenylphosphine-platinum(II) and tin(II) chloride, soybean oil methyl ester shows an increase in monoene, a decrease in
diene and triene, and formation of conjugatedcis-trans andtrans-trans dienes, but no increase in stearate. Similarly, methyl oleate and methyl linoleate were converted to trans monoene, but not
to stearate.
Hydrogenations with mixtures of tetrachloroplatinum(II) ion or hexachloro-platinum(IV) ion and tin(II) chloride were similar
to those described above but they form some stearate.
Several other metal ions were studied as replacements for tin. None of them were effective. 相似文献
2.
G. Ben-Et A. Dolev M. Schimmel R. Stern 《Journal of the American Oil Chemists' Society》1972,49(4):205-207
A new approach to the selective hydrogenation of unsaturated fatty acids is suggested. It consists of a two step process.
The first is a selective conjugation of the double bonds, while the second consists of the hydrogenation reaction using a
catalyst which is specific to conjugated systems. Potassiumt-butoxide was used as a conjugation catalyst and its activity and selectivity were tested at various concentrations, different
molar ratios of catalyst to oil, and in various solvents. Phenanthrene chromium tricarbonyl was used as the hydrogenation
catalyst and its activity tested at various concentrations, temperatures and in various solvents.
UN Expert, Physical Organic Chemist. 相似文献
3.
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
4.
Maj-Britt Macher Johan Hgberg Poul Mller Magnus Hrrd 《European Journal of Lipid Science and Technology》1999,101(8):301-305
Under supercritical or near-critical conditions propane is a very good solvent for both lipids and hydrogen. Thus, it is possible to generate an essentially homogeneous phase, in which the transport resistances for the hydrogen are eliminated. Therefore, the hydrogen concentration at the catalyst surface can be greatly increased, resulting in extremely high reaction rates and products having low trans fatty acid contents. In this study we present results from hydrogenation of rapeseed fatty acid methyl esters under near-critical and supercritical conditions. Temperature, residence time, hydrogen pressure, and catalyst life were varied systematically, using a statistical experimental design, in order to elucidate reaction rate and trans fatty acid formation as functions of the above variables. The experiments were carried out in a microscale fixed-bed reactor, using a 3% Pd-on-aminopolysiloxane catalyst. At 92 °C, a hydrogen pressure of 4 bar, and a residence time of 40 ms we obtained a trans content of 3.8 ± 1.7% at a iodine value of 70. Our results support the findings from traditional processes that at a constant iodine value (IV) the trans content decreases with decreasing temperature, increasing pH2, and increasing residence time. The reaction rate at our best conditions was roughly 500 times higher than in traditional batch hydrogenation. 相似文献
5.
Ovidiu Popescu Sambasivarao Koritala H. J. Dutton 《Journal of the American Oil Chemists' Society》1969,46(2):97-99
High oleic (monoene) oils were obtained from soybean oil by selective hydrogenation with copper catalysts. A mixture of nickel
and copper chromite catalyst had activity suitable for producing the high monoene oils. A new catalyst (copper-on-Cab-O-Sil)
prepared in the Laboratory was more active than commercial copper catalysts. Hydrogenated oils contained 61–72% monoenoic
and 14–24% dienoic acids, and there was essentially no increase in stearic acid. Thetrans-isomer content of these oils varied between 17% to 32%. Double bonds in the monoene were distributed along the molecule from
C6 to C15, but were located preferentially in the C9 position for thecis-monoene and in the C10 and C11 positions for thetrans-monoene. When the iodine value of these high monoene oils was about 90–95, they remained liquid above 28 C. Citric acid treatment
reduced the copper content of hydrogenated oils to a level that was comparable to that of the original soybean oil.
Presented at the AOCS Meeting, Chicago, October 1967.
Food and Agricultural Organization representative from Rumania.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
6.
Triacyl glycerides (TGs) are naturally occurring oils produced by a significant variety of crops, microorganisms (bacteria and algae), and animals (certain fats). The diversity and prevalence of the sources of these compounds suggest that they may serve as an attractive alternative to crude oil as the feedstock for the production of transportation fuels and certain industrial chemicals — organic compounds with carbon chain lengths in the range of C7 to C15. In the present study a series of batch thermal cracking reactions was performed using soybean oil and canola oil under reaction conditions leading towards attractive yields of potentially valuable (as fuels and/or chemicals) shorter chain products. An attractive yield of alkanes and fatty acids (from oil cracking) or esters (from biodiesel) was obtained. From a parametric study reaction temperature, followed by residence time, was found to have the most significant effect. Significantly, cracking under increased pressures in a hydrogen atmosphere did not improve the yields of desirable species. 相似文献
7.
Howard M. Teeter 《Journal of the American Oil Chemists' Society》1948,25(7):243-245
- The reaction of N-bromosuccinimide with methyl esters of soybean fat acids and with methyl linoleate has been investigated, and the influence of changes in the conditions of reaction has been studied.
- The reaction of brominated methyl esters of soybean fat acids with sodium methoxide produced both methoxylated products and a dimer-like substance.
- The reaction of brominated methyl esters of soybean fat acids with sodium cyanide and cuprous cyanide did not result in significant replacement of bromine with the cyano group.
8.
Journal of the American Oil Chemists' Society - 1 相似文献
9.
A silica-bonded complex was prepared by reacting polyphenylsiloxane with silylated Chromosorb and then with Cr(CO)6. This complex catalyzed stereoselective hydrogenation of sorbate tocis-3-hexenoate. Soybean methyl esters were hydrogenated at 210 C in cyclohexane to form products high incis unsaturation. The recovered catalyst could be recycled once with methyl sorbate. IR showed decreased Cr(CO)3 in the recovered catalysts, and the hydrogenation products contained inactive Cr. 相似文献
10.
尽管部分加氢是提高多不饱和脂肪酸及其酯性能的一种有效方式,但加氢过程中反式异构体的生成会影响油脂的品质,因此,对油脂加氢反应中如何减少反式异构体生成的研究具有一定的意义。首先,介绍了多不饱和脂肪酸及其酯加氢机理及反式异构体生成的原理。然后,综述了加氢方式、加氢催化剂(包括活性组分、助剂、载体及催化剂制备方法)对反式异构体生成影响的研究新进展。最后,对影响反式异构体生成的规律进行总结,进而提出了多不饱和脂肪酸及其酯加氢过程中以减少反式异构体生成为目的的措施。 相似文献
11.
Bryan R. Moser Michael J. Haas Jill K. Winkler Michael A. Jackson Sevim Z. Erhan Gary R. List 《European Journal of Lipid Science and Technology》2007,109(1):17-24
Biodiesel, an alternative fuel derived from vegetable oils or animal fats, continues to undergo rapid worldwide growth. Specifications mandating biodiesel quality, most notably in Europe (EN 14214) and the USA (ASTM D6751), have emerged that limit feedstock choice in the production of biodiesel fuel. For instance, EN 14214 contains a specification for iodine value (IV; 120 g I2/100 g maximum) that eliminates soybean oil as a potential feedstock, as it generally has an IV >120. Therefore, partially hydrogenated soybean oil methyl esters (PHSME; IV = 116) were evaluated as biodiesel by measuring a number of fuel properties, such as oxidative stability, low‐temperature performance, lubricity, kinematic viscosity, and specific gravity. Compared to soybean oil methyl esters (SME), PHSME were found to have superior oxidative stability, similar specific gravity, but inferior low‐temperature performance, kinematic viscosity, and lubricity. The kinematic viscosity and lubricity of PHSME, however, were within the prescribed US and European limits. There is no universal value for low‐temperature performance in biodiesel specifications, but PHSME have superior cold flow behavior when compared to other alternative feedstock fuels, such as palm oil, tallow and grease methyl esters. The production of PHSME from refined soybean oil would increase biodiesel production costs by US$ 0.04/L (US$ 0.15/gal) in comparison to SME. In summary, PHSME are within both the European and American standards for all properties measured in this study and deserve consideration as a potential biodiesel fuel. 相似文献
12.
Selective hydrogenation of soybean oil: XII. Trialkyl aluminum-copper stearate homogeneous catalysts
S. Koritala 《Journal of the American Oil Chemists' Society》1982,59(7):309-312
The reaction of copper stearate with triethylaluminum (TEAL) formed a soluble catalyst that promoted the selective hydrogenation
of the linolenyl groups in soybean oil. This homogeneous catalyst was more active than copper-chromite. The activity was enhanced
by the addition of silica, alumina or titania. Ethyl alcohol accelerated the hydrogenation when it was added in small amounts
and retarded hydrogenation when increased amounts were added. More active and, in some cases, more selective catalysts were
formed when TEAL was replaced by trialkylaluminum compounds containing longer chain length in the alkyl groups. Among other
organometallics tested, diethylmagnesium and diisobutylaluminum ethoxide formed catalysts with activity comparable to heterogeneous
catalysts (KLe/KLo=2.8~5.2) was less than that obtained with copper-chromite (12~14), but greater than that of commercially used nickel catalysts
(2). Isomerization, as measured by the percentage oftrans isomers formed, was similar to that of heterogeneous copper catalysts (%trans/ΔIV=0.6~0.7).
Presented at the AOCS meeting in New Orleans, May 1981. 相似文献
13.
E. N. Frankel J. P. Friedrich T. R. Bessler W. F. Kwolek N. L. Holy 《Journal of the American Oil Chemists' Society》1980,57(10):349-354
New polymer-bound hydrogenation catalysts were made by complexing PdCl2, RhCl3·3H2O, or NiCl2 with anthranilic acid anchored to chloromethylated polystyrene. The Pd(II) and Ni(II) polymers were reduced to the corresponding
Pd(O) and Ni(O) catalysts with NaBH4. In the hydrogenation of methyl sorbate, these polymer catalysts were highly selective for the formation of methyl 2-hexenoate.
The diene to monoene selectivity decreased in the order: Pd(II), Pd(O), Rh(I), Ni(II), Ni(O). Kinetic studies support 1,2-reduction
of the Δ4 double bond of sorbate as the main path of hydrogenation. In the hydrogenation of soybean esters, the Pd(II) polymer
catalysts proved superior because they were more active than the Ni(II) polymers and produced lesstrans unsaturation than the Rh(I) polymers. Hydrogenation with Pd(II) polymers at 50~100 C and 50 to 100 psi H2 decreased the linolenate content below 3% and increasedtrans unsaturation to 10~26%. The linolenate to linoleate selectivity ranged from 1.6 to 3.2. Reaction parameters were analyzed
statistically to optimize hydrogenation. Recycling through 2 or 3 hydrogenations of soybean esters was demonstrated with the
Pd(II) polymers. In comparison with commercial Pd-on-alumina, the Pd(II) polymers were less active and as selective in the
hydrogenation of soybean esters but more selective in the hydrogenation of methyl sorbate.
Presented at ISF-AOCS Meeting, New York, April 1980. 相似文献
14.
15.
The electrocatalytic hydrogenation of soybean oil 总被引:2,自引:0,他引:2
Soybean oil has been hydrogenated electrocatalytically at a moderate temperature, without an external supply of pressurized
H2 gas. In the electrocatalytic reaction scheme, atomic hydrogen is produced on an active Raney nickel powder cathode surface
by the electrochemical reduction of water molecules from the electrolytic solution. Adsorbed hydrogen then reacts with an
oil’s triglycerides to form a hydrogenated product. Experiments were carried out at 70°C with a flow-through electrochemical
reactor operating in a batch recycle mode. The reaction medium was a two-phase mixture of soybean oil in a water/t-butanol
solvent containing tetraethylammoniump-toluenesulfonate as the supporting electrolyte. In all experiments the reaction was allowed to continue for sufficient time
to synthesize a brush hydrogenation product. The effects of oil content, applied current, solvent composition, and supporting
electrolyte concentration on the efficiency of hydrogen addition to the oil and on the chemical properties of the hydrogenated
oil product were determined. The electrohydrogenated oil is characterized by a high stearic acid content and a low percentage
of totaltrans isomers, as compared to that produced in a traditional hydrogenation process. 相似文献
16.
C. Boelhouwer J. Gerckens Ong Tian Lie H. I. Waterman 《Journal of the American Oil Chemists' Society》1953,30(2):59-61
Summary The displacement of the double bond of several unsaturated fatty acid methyl esters during hydrogenation with a nickel-kieselguhr
catalyst at 180°C. was investigated. The analysis of the dicarboxylic acids (obtained by oxidation of the reaction products
with KMnO4 in acetic acid solution) by means of partition chromatography enabled a reliable semiquantitative determination of the position
isomers formed.
During hydrogenation of methyl esters of oleic, elaidic, petroselinic, and linoleic acid formation of large amounts of position
isomers was proved to occur. Migration of the double bonds in both directions took place but was in all cases strongly pronounced
in a direction opposite the ester group. The place and configuration (cis or trans) of the double bonds in the starting material
apparently were of little importance in this respect. It follows that hydrogenation of fatty acid esters leads to products
which are far more complicated, as is generally known. This is especially of importance with respect to the application of
hydrogenated fatty oils in the food industries. 相似文献
17.
Bryan R. Moser 《European Journal of Lipid Science and Technology》2008,110(12):1167-1174
The antioxidant activity of myricetin, a natural flavonol found in fruits and vegetables, was determined in soybean oil methyl esters (SME) and compared with α‐tocopherol and tert‐butylhydroquinone (TBHQ) over a 90‐day period employing EN 14112, acid value, and kinematic viscosity methods. Myricetin had greater antioxidant activity than α‐tocopherol, but was inferior to TBHQ. Synergism was observed between myricetin and TBHQ, but antagonism between α‐tocopherol and either myricetin or TBHQ was discovered. A binary mixture of myricetin and TBHQ at 1000 ppm (1:1) was the most effective treatment investigated at inhibiting oxidation of SME. Myricetin was not completely soluble in SME at 1000 ppm, suggesting that 500 ppm is a more appropriate treatment level. Pro‐oxidant activity of α‐tocopherol was observed when added to SME obtained from crude soybean oil, but antioxidant behavior was observed in distilled SME. Addition of α‐tocopherol to methyl esters initially free of antioxidants revealed that 600–700 ppm was the optimum concentration for antioxidant activity. Acid value and kinematic viscosity remained within prescribed specifications after 90 days, despite failure of a number of samples with regard to EN 14112, suggesting that these parameters are insufficient as sole indicators of oxidation stability. 相似文献
18.
19.
T. Tagawa T. Nishiguchi K. Fukuzumi 《Journal of the American Oil Chemists' Society》1978,55(3):332-336
The selective hydrogenation of methyl linoleate was studied using various organic compounds as hydrogen sources in the presence
of homogeneous and metallic palladium catalysts. Complete selectivity to monoenes and relatively little formation of isolatedtrans double bonds were realized by the hydrogen transfer from L-ascorbic acid at 47% conversion of starting material to hydrogenation
products. The hydrogenation bytrans-1,2-cyclohexanediol catalyzed by RuH2(PPh3)4 also showed rather high selectivity tocis-monoenes. In the reaction catalyzed by RuH2(PPh3)4, also showed rather high selectivity tocis-monoenes. In the reaction catalyzed by RuH2(PPh3)4, the presence of these hydroxy compounds increased the isomerization of methyl elaidate tocis-monoenes. 相似文献
20.
Intrinsic selectivities and yields in the catalytic hydrogenation of polyenoic fatty acid methyl esters 总被引:1,自引:0,他引:1
Ricardo J. Grau Alberto E. Cassano Miguel A. Balfanás 《Journal of the American Oil Chemists' Society》1990,67(4):226-232
Precise values of the intrinsic selectivities and yields for the hydrogenation products of methyl linolenate (Ln) and methyl
linoleate (L) obtained under carefully controlled conditions using a commercial Ni catalyst are presented and analyzed in
detail. The existence of a preferential adsorption of Ln and a significant co-hydrogenation of its double bonds are confirmed
as being the dominant features under typical vegetable oil processing conditions.
It is shown that the values of the selectivities that are obtained from the classical consecutive reactions network account
for the intrinsic selectivity of the catalyst only while hydrogenating feedstocks with moderate to low (<10%) contents of
Ln.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Lltoral (U.N.L.) 相似文献