Epoxidation of oleic acid

Epoxidation of oleic acid over Ti-beta prepared in fluoride (F) and alkali (OH) medium... 

P6-25c Oleic acid epoxide (E) is produced by the catalytic epoxidation of oleic acid (OA) [J. Fotopoulos, C. Georgakis, and H. Stenger, Chem. Eng. Sci, 51, 1899 (1996)]. The raw materials are pure benzaldehyde (B) and oleic acid (OA). Unfortunately, undesired products are also formed, including benzoic (BA) and perbenzoic acids (PBA). The reaction sequence is... 

The epoxidation of petrochemical alkenes is an intensely investigated oxidation reaction and in recent years numerous homogeneous catalysts have been developed for this reaction. However, so far the catalytic epoxidation of fatty compounds has been investigated only marginally. Sobczak and Ziolkowski reported on the epoxidation of oleic acid with organic hydroperoxides catalyzed by molybdenum complexes [37]. Typical homogeneous catalysts include Mo(CO)6 and Mo02(acac)2. 

Fig. 2. Epoxidation of oleic acid by autoxidation of benzaldehyde to perbenzoic acid in situ. Source Ref. 7.

To escape the dilemma between using pure but risky preformed peroxy acids and in situ peroxy acid formation accompanied by a strong acid fliat may decrease selectivity, peroxy acids have been generated from aldehydes and molecular oxygen catalyzed by transition metal compoimds. This technique has also been applied to the epoxidation of oleic acid (7). Benzaldehyde was used as the peroxy acid source and Co " as the catalyst (Fig. 2) the yield was 83% at 100% conversion after 1.5 h. In a similar way, 0-marked epoxy fatty acid esters have been synthesized (8). 

The in situ procedure as proposed by Sonnet et al. (18) is much more attractive for synthetic applications. With the use of only a moderate excess of monopersulfate (C=C KHSO5 = l 2-2.4), they achieved an 80% yield for the epoxidation of oleic acid methyl ester and 81-96% for the epoxidation of various plant oils. It is a twophase reaction with a crown-ether as phase-transfer catalyst yet a considerable amount of inorganic waste (six times the weight of the product) is produced. In a recent work (21), the phase-transfer catalyst was replaced by acetonitrile as a polar solvent. In summary, epoxidation by dioxiranes is a promising new method for oleo-chemistry, especially because it also works in combination with metal catalysts to influence diastereoselectivity (22) an enantioselective epoxidation with sugardioxiranes has also been reported (23). 

Kuo, M.-C, and T.-C. Chou, Epoxidation of Oleic Acid with Oxygen in the Presence of Benzaldehyde Using Heterogenized Homogeneous Co-Type Ion-Exchange Membrane as Catalyst, Can, J. Chem. Eng. 68 831-838 (1990). 

In addition, the pencil scratch hardness of the present film was improved, compared to that of the cured film obtained from a polyester having an unsaturated fatty acid in the side chain. The enzymatic epoxidation of oleic acid, followed by the intermolecular ring-opening addition, yielded the polymer, which could be cured with diisocyanate [113]. 

Correa, FA Sutili, FK Miranda, LSM Leite, SGF Souza, ROMA Leal, ICR. Epoxidation of oleic acid catalyzed by PSCI-Amano lipase optimized by experimental design. Journal of Molecular Catalysis B Enzymatic, 2012, V. 81,7-11. 

Kuo, M.C., Chou, T.C., 1987. Kinetics and mechanism of the catalyzed epoxidation of oleic-acid with oxygen in the presence of benzaldehyde. Ind. Eng. Chem. Res. 26, 277-284. 

Lennarz and Bloch (1960) have prepared 9-hydroxystearic acid-H from naturally occurring J -9-hydroxyoctadecenoic acid by catalytic hydrogenation, and racemic 10-hydroxystearic acid through epoxidation of oleic acid, and tested them as possible precursors to olefinic acids in two ways. Both were as efficient as oleic acid in satisfying the unsaturated fatty acid growth requirement of yeast raised under strictly anaerobic conditions, suggesting that they were desaturated to olefinic acids in vivo. 9-Hydroxystearic acid-H in addition was incubated with yeast homogenate in the presence of TPNH, ATP, and CoA, and yielded a monounsaturated acid with a double bond in the vicinity of C-8 to C-10. 

Typically, soHd stabilizers utilize natural saturated fatty acid ligands with chain lengths of Cg—C g. Ziac stearate [557-05-1/, ziac neodecanoate [27253-29-8] calcium stearate [1592-23-0] barium stearate [6865-35-6] and cadmium laurate [2605-44-9] are some examples. To complete the package, the soHd products also contain other soHd additives such as polyols, antioxidants, and lubricants. Liquid stabilizers can make use of metal soaps of oleic acid, tall oil acids, 2-ethyl-hexanoic acid, octylphenol, and nonylphenol. Barium bis(nonylphenate) [41157-58-8] ziac 2-ethyIhexanoate [136-53-8], cadmium 2-ethyIhexanoate [2420-98-6], and overbased barium tallate [68855-79-8] are normally used ia the Hquid formulations along with solubilizers such as plasticizers, phosphites, and/or epoxidized oils. The majority of the Hquid barium—cadmium formulations rely on barium nonylphenate as the source of that metal. There are even some mixed metal stabilizers suppHed as pastes. The U.S. FDA approved calcium—zinc stabilizers are good examples because they contain a mixture of calcium stearate and ziac stearate suspended ia epoxidized soya oil. Table 4 shows examples of typical mixed metal stabilizers. 

The lower activity of Ti-beta(OH) in the epoxidation of an alkene containing a polar head (oleic acid, Table XI) was attributed by Blasco et al. (13) to the different adsorption properties of the two catalysts. A strong adsorption of oleic acid through the polar head on the relatively more hydrophilic Ti-beta(OH)... 

Intramolecular epoxidation is also possible with this system.2 Thus treatment of the ortho ester (1) of oleic acid with H202 in CH2C12 leads to the epoxide 2 in 40% yield, probably via the intermediate a. 

Another oil used for epoxidation with MT0/H202 is the oil from Jatropha curcas L. also known as Barbados or Physic nut. As with palm oil, it mostly consists of oleic acid (50%) and linoleic acid (29%) and various saturated fatty acids (20%). With 0.5 mol% of MTO and 12 mol% of pyridine in biphasic conditions, it was found that Jatropha oil can be completely epoxidized within 1.5 h [78]. 

Some insects use hydrocarbons as sex pheromones. For example, the housefly, Musca domestica, uses a mixture including (Z) -9-tricosene, the corresponding epoxide and ketone, and several methyl alkanes (2iI). The tricosene is derived by chain elongation of oleic acid, and the epoxide and ketone are made from it. The methyl alkanes are made de novo from acetate and propionate, with one propionate unit per molecule supplying the branch carbon. Propionate can arise from the degradation of valine or isoleucine, but not from succinate, although succinate may serve as an acetate precursor. 

In Sec. 17.10 a mechanism is proposed for the conversion of ethylene bromo-hydrin into ethylene oxide in the presence of base, (a) To what general class does this reaction belong (b) Using models, show the likely steric course of this reaction, (c) Can you suggest a reason why sodium hydroxide readily converts /r<7/i5-2-chlorocyclohexanol into cyclohexene oxide, but converts the c/5-isomer into entirely different products (d) Account for the fact that addition of chlorine and water to oleic acid (c(5-9-octadece-noic acid) followed by treatment with base gives the same epoxide (same stereoisomer) as does treatment of oleic acid with a peroxy acid. 

Another early discovery was that CALB accepts H202 as nucleophile to produce peroxycarboxylic acids from esters or carboxylic acids (perhydrolysis activity can also be found in other serine hydrolases) [46, 47]. The in situ formed peracid can subsequently be used to epoxidize an alkene by (non-enzymatic) Prileshajev epoxidation. Hence, oleic acid incubated with CALB and H202 will produce 9,10-epoxyoctadecanoic acid [48]. Other alkenes can be epoxidized by H202 and a catalytic amount of carboxylic acid (and CALB) (Scheme 13.2) [49],... 

Inhaled ozone is known to initiate free-radical autooxidation of unsaturated fatty acids in animal pulmonary lipids (Pryor et al., 1981). These reactions lead to the formation of such typical autooxidation products as conjugated dienes and short-chain alkanes like ethane and pentane. Whether these reactions also occur in water treatment is uncertain. Glaze et al. (1988) showed that 9-hexadecenoic acid (83) reacted readily in aqueous solution to form the expected C, and C, aldehydes and acids. Linoleic acid (84) was converted to a mixture of aldehydes and acids (Carlson and Caple, 1977) notably, 3-nonenal (85) was among the products. Isolation of an unsaturated aldehyde is significant because of the high reported toxicity of these compounds. Carlson and Caple (1977) also implied that the epoxide of stearic acid was formed when an aqueous solution of oleic acid was ozonized the product probably derives from an indirect attack on the double bond by peracids or peroxy radicals (Equation 5.39). Nevertheless, it is conceivable that similar reactions could occur in natural waters. 

Epoxidation of oleic and linoleic acid was readily achieved by treatment with the acetonitrile complex of hypofluorous acid (55). Phase-transfer-catalyzed biphasic epoxidation of unsaturated triglycerides was accomplished with ethylmethyldioxirane in 2-butanone (56). The enantioselective formation of an a,P-epoxy alcohol by reaction of methyl 13()S)-hydroperoxy-18 2(9Z,llfi) with titanium isopropoxide has been reported (57). An immobilized form of Candida antartica on acrylic resin (Novozyme 435) was used to catalyze the perhydrolysis and the interesterification of esters. Unsaturated alcohols were converted with an ester in the presence of hydrogen peroxide to esters of epoxidized alcohols (e.g., epoxystearylbutyrate) directly (58). Homoallyl ethers were obtained from olefinic fatty esters by the ethylaluminium-in-duced reactions with dimethyl acetals of formaldehyde, acetaldehyde, isobutyralde-hyde, and pivaldehyde (59). Reaction of 18 2(9Z, 12Z) with 50% BF3-methanol gave monomethoxy and dimethoxy derivatives (60). A bulky phosphite-modified rhodium catalyst was developed for the hydroformylation of methyl 18 1 (9Z)and 18 1(9 ), which furnished mixtures of formylstearate and diformylstearate (61). 

The epoxidation reactions can also be confirmed by ]-NMR. Figure 22.17a and b show, respectively, the C-NMR spectra of the oleic acid and the epoxidized oleic acid. The disappearance of vinylic carbons at 5= 130 ppm of oleic acid and the appearance of epoxidihc carbons at 5=54.3-57.2 ppm in the C-NMR spectra of epoxidized oleic add are observed. 

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