Methyl oleate reduction

Reduction of ozonides is very useful, especially when aldehydes are the desired products. Ozonides are easily hydrogenolyzed over palladium [670], or reduced by zinc in acetic acid [671], usually in good yields. Ozonolysis of methyl oleate followed by hydrogenation over 10% palladium on charcoal... 

Inactivated alkenes are oxidatively cleaved by the hydrotrioxide to give ketones. For example, methyl oleate 73 reacts with the hydrotrioxide to produce two aldehydes, followed by LiAlFLj reduction to give 1-nonanol and nonane-1,9- diol in 64 and 74% yields (equation 81). 

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... 

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. 

The desired increase in melting point is achieved by partial hydrogenation. Complete reduction would produce a fat with too high a melting point. The products of partial hydrogenation, however, are more complex than might have been predicted and understanding of this topic has developed from studies with individual esters such as methyl oleate, linoleate and linolenate. Useful information has also come from deuteration studies. 

Starting from oleic acid, [52] 9,10-dihydroxy-8,8,ll,l W4 was obtained after oxidation to 9,10-dioxo derivative followed by hydrogen-deuterium exchange as shown in Figure 4 and reduction of he keto groups to hydroxy groups. The product obtained was converted to methyl oleate-8,8,11,11- 4 in turn, the latter was used, together with others deuterium-labelled compounds, such as oleic acid-9, IO-J2 and Z-methionine-methyl-Js, to elucidate the... 

In Table 2.5 is shown a strong reduced mechanism for biodiesel, given here in terms of the methyl oleate, C19H36O2. A strong reduction is desired to permit the solution of both problems, turbulence and chemical kinetics, with nonprohibitive computational times. 

The simple reaction with mercuric acetate and methanol, followed by reduction with sodium borohydride, converts methyl oleate, for example, into a mixture of methyl 9- and 10-methoxystearates. Other mono- and poly-enoic esters behave in a similar way and it is possible by g.c.—m.s. to identify these reaction products and so determine the position of unsaturation in the original ester. ... 

Tritiated oleate was prepared by catalytic reduction of one of the two double bonds of linoleic acid. To 5 mCi of NaBT4 (13.9 pmol) in 0.5 mL diethyl ether and 5 mg of 10% PdA3 was added 156 pL of 100 mg linoleic acid (55.7 pmol) (in 1 ml diethyl ether [7]). The free linoleic acid was added slowly (15 pL per min) formed sufficient tritium gas to stoichiometrically hydrogenate one of the two double bonds. The reaction mixture was taken to dryness under nitrogen, treated with 0.250 mL 10% methanolic HCl, heated to 70° for 1 hour to prepare the methyl ester. The product was separated by preparative TLC on silver impregnated silica gel as above. Three major radioactive peaks were observed, in addition to some material near the origin. The major radioactive peak corresponded with methyl oleate, the second peak with methyl vaccinate and the third peak was unidentified. 

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