Methyl oleate, selective

The ability of titanium-grafted silicas in catalyzing the epoxidation with TBHP of fatty compounds was first tested on two pure Qg monounsaturated FAMEs methyl oleate (ds-9-octadecenoate Scheme 12.1) and methyl elaidate (trans-9-octadecenoate) [49]. In both cases, selectivity to 9,10-epoxystearate was very high (>95%) and the reaction was fully stereospecific, confirming that epoxidation with titanium catalysts and TBHP proceeds via a non-radical mechanism with retention of configuration at the C=C bond. Ti-MCM-41 was more active than Ti-SiC>2 (Fig. 12.1). Actually, methyl oleate was almost completely converted after... 

The application of olefin metathesis to fatty acids and related compounds has its starting point in 1972 with the selective transformation of methyl oleate into equimolar amounts of 9-octadecene and dimethyl 9-octadecene-l,18-dioate by Van Dam, Mittelmeijer, and Boelhouwer (Scheme 1) [29]. In this early work, 1-2 mol% of a... 

The production of a,m-diesters from fatty esters can be realized via their SM as already explained, but it can also be performed by CM with methyl acrylate. The bulk CM of several unsaturated fatty acid methyl esters containing double bonds in different positions with methyl acrylate was studied by Rybak and Meier (Scheme 6) [43], C4 and C5 displayed very good activities with high conversions and CM selectivities. Among them, C5 showed the best performance for both methyl oleate (97% conversion, 92% selectivity, with 0.2 mol%) and methyl 10-undecenoate (99% conversion, 99% selectivity, with 0.1 mol%). The same conditions were successfully applied to methyl erucate and methyl petroselinate. The reaction conditions were further optimized, also considering the effect of 1,4-benzoquinone as additive for the reduction of double-bond isomerization [39], The CM of methyl 10-undecenoate and methyl acrylate worked with full conversions and high selectivity if five- to tenfold excess of methyl acrylate is used. Furthermore, using a 1 1 ratio between both reactants led, after optimization of the reaction... 

Several other terminal and internal olefins were used as model compounds in this reaction. 1-Octene, 2-octene, 3-octene, and 4-octene and methyl oleate showed very high selectivity for linear products. At 40°C and 20 bar CO pressure, 83% of the methyl oleate was converted to the linear a,( -diesters with a 95% selectivity for linear products over 22 h. 

Albright, L. and Wisniak, J., J. Amer. Oil Chem. Soc. 39, 14, 1962. Selectivity and Isomerization during Partial hydrogenation of cottonsead oil and methyl oleate Effect of operating variables. ... 

It is also possible to shift the equilibrium of the reaction by removing the formed reaction products (according to the Le Chatelier s principle) (162). For example, the ability to remove water in continuous esterification reactions in SCCO2 has been cited as one of the advantages of using SCCO2 versus traditional solvents, such as hexane (163). In their study on the interesterification of tricaprylin and methyl oleate in SCCO2, Adschiri et al. (164) concluded that the selective extraction of the reaction product, methyl caprylate shifted the equilibrium of the reaction forward. 

Again, it is important to note that methyl esters of lard and tallow are the sum of the methyl esters of fatty acids found in the original fat. Methyl lard for example, will contain methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, and methyl linolenate in the same percentages as the lard used as the raw material, unless the manufacturer fractionates the material, thereby selecting methyl esters of certain fatty acids over others. 

To elucidate the mechanism of homogeneous hydrogenation catalyzed by Fe(CO)s, kinetic studies were carried out with mixtures of unsaturated fatty esters containing a radioactive label. A C-labeled methyl octadecadienoate-Fe(CO)3 complex was prepared to serve as a catalytic intermediate. Hydrogenation of methyl oleate (m-9-octa-decenoate) and palmitoleate (cis-9-hexadecenoate) and of their mixtures with methyl linoleate was also studied to determine the selectivity of this system, the function of the diene-Fe(CO)3 complex, and the mechanism of homogeneous isomerization. Mixtures of reaction intermediates with a label helped achieve unique simulation of the kinetic data with an analog computer. 

The Fe(CO)4 intermediates of types III and VIII in Scheme IV explain the direct reduction paths evidenced in the hydrogenation of mono- and diunsaturated fatty esters. Competition between monoene and diene hydrogenation can be related to the stability of the Fe(CO)3-and Fe(CO)4-complexes. At a low concentration of Fe(CO)5, the formation of Fe(CO)a complexes is favored because they are more stable. At a high concentration of Fe(CO)s, formation of mono- and di-Fe(CO)4 complexes becomes important, and selectivity for diene hydrogenation is decreased. Although the occurrence of olefin-Fe(CO)4 complexes has precedence in the literature (i9), no such species has yet been identified with either methyl oleate or linoleate. 

Y. Pouilloux, A. Piccirilli and J. Barrault, "Selective hydrogenation into oleyl alcohol of methyl oleate in the presence of Ru-Sn/ALOi catalysts" J. Mot. Catal A Chemical, 108,161 (1996). 

Barrault and co-workers studied the selective hydrogenation of methyl oleate into oleyl alcohol over RuSnB/alumina catalysts. The yield of oleyl alcohol was 75 % at 90 % methyl oleate conversion over a RuSnB/AbOa catalyst for a bulk atomic ratio Sn/Ru of 4. Over such catalysts the reaction involves three steps (1) the hydrogenation of the methyl oleate into the oleyl alcohol, (2) the transesterification between the methyl oleate and the oleyl alcohol with the formation of the heavy oleyl oleate ester, (3) the hydrogenolysis of this heavy ester into oleyl alcohol. The first and the third steps could involve mixed ruthenium-tin sites with two SnOx (x = 2) species, while the second could require tin species without... 

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