Methyl linolenate

Additional evidence indirectly supports the reversibiUty of reaction 2. The addition of oxygen to a highly conjugated radical is readily reversible even at 40°C according to a study of the isomerization of methyl linolenate hydroperoxides in the presence of 02 (95). 

Figure 1.7 Typical zero-order and corresponding second-derivative electronic absorption spectra of ethanol-reconstituted lipid/chloroform extracts of autoxidized model polyunsaturated fatty-acid compounds and inflammatory synovial fluid obtained after (1) reduction with NaBH4 and (2) dehydration with alcoholic H2S04- (a) Methyl linoleate subsequent to autoxidation in air at ambient temperature for a period of 72 h (—), or exposure to a Fenton reaction system containing EDTA (5.75 x 10 mol/dm ), H2O2 (1.14 X 10 mol/dm ) and Fe(ll) (5.75 x IO mol/dm ) as an aqueous suspension (—) (b) as (a) but with methyl linolenate (c) untreated rheumatoid knee-joint synovial fluid.

Silica has often been modified with silver for argentation chromatography because of the additional selectivity conferred by the interactions between silver and Jt-bonds of unsaturated hydrocarbons. In a recent example, methyl linoleate was separated from methyl linolenate on silver-modified silica in a dioxane-hexane mixture.23 Bonded phases using amino or cyano groups have proved to be of great utility. In a recent application on a 250 x 1-mm Deltabond (Keystone Scientific Belief onte, PA) Cyano cyanopropyl column, carbon dioxide was dissolved under pressure into the hexane mobile phase, serving to reduce the viscosity from 6.2 to 1 MPa and improve efficiency and peak symmetry.24 It was proposed that the carbon dioxide served to suppress the effect of residual surface silanols on retention. 

C12 to C20, primarily Ci6 to ( is), used as surface lubricants in the manufacture of food-contact articles. The method, which uses ethyl palmitate (Eastman Chemicals No. 1575 Red Label) as an internal standard, has been validated at 200 ppm total FAME [185]. Other FAME standards (methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate) are available (Applied Science Laboratories) [116], Worked out examples of additive determinations are given in the Food Additives Analytical Manual [116], which also describes a great many of indirect food additives, such as BHA, BHT, TBHQ, l-chloro-2-propanol, DLTDP, fatty acid methyl esters, w-heptyl-p-hydroxybenzoate, propyl-gallate, sodium benzoate, sodium stearoyl-2-lactylate, sorbitol and phenolic antioxidants. EPA methods 606 and 8060 describe the CGC separation of phthalate esters (direct injection) (cf. Figure 4.2). 

As a reasonable biogenetie pathway for the enzymatic conversion of the polyunsaturated fatty acid 3 into the bicyclic peroxide 4, the free radical mechanism in Equation 3 was postulated 9). That such a free radical process is a viable mechanism has been indicated by model studies in which prostaglandin-like products were obtained from the autoxidation of methyl linolenate 10> and from the treatment of unsaturated lipid hydroperoxides with free radical initiators U). 

Larva Inhibits worker ovarian development Ten component blend of brood pheromone methyl ethyl palmitate 78 79, stearate 80 81, oleate 56 90,linoleate 82 83, linolenate 84 84a, specifically ethyl palmitate methyl linolenate [121,122]... 

Low levels of nitrogen dioxide react with the polyunsaturated fatty acids under anaerobic conditions to give allylic nitro and allylic nitrite derivatives of methyl linoleate and methyl linolenate. These were identified by NICI-MS558. 

Materials. The catalyst, PdCl2 (Fisher Scientific, dry, purified grade) and Ph3P (Strem Chemicals) were used as purchased. Methyl linoleate, alkali-conjugated methyl linoleate (cis,trans-9,11- and 10,12-octadeca-dienoate), and methyl linolenate were prepared as before (21). 

Branch Carbon Methyl Linoleate Conjugated Linoleate, Methyl Linolenate)... 

Methyl Tricarboxyoctadecanoate, 3. The product from Run 12, Table I, was characterized functionally by comparing GLC, TLC, and mass spectra of corresponding derivatives from hydroformylated methyl linolenate (21). Mass spectrum m/e (fragment, relative intensity) 472... 

Figure 8. Rate curves for hydrocarboxylation of methyl linolenate with PdCl2-Ph3P at 120°C, 4000 psi CO (Run 11)...

Figure 8 shows kinetic data on the catalytic hydrocarboxylation of methyl linolenate. There is initial conjugation of the triene system. Monocarboxy acids formed as initial products peak after 2 hrs and disappear almost completely. The dicarboxy acids are important intermediates and carboxylate further to give tricarboxy acids. The conversion to tricarboxy acids at 140°C does not exceed 50 to 53% (Runs 9 and 11, Table I). Cyclic ketones are formed as in linoleate in small but significant amounts. 

Fig. 16 Separation of isomerized methyl linolenate. Sample size 20 fig. Flow rate 1.0 ml/min 0.125% ACN in hexane. UV detection at 210 nm. Groups A = three trans B = two trails, one cis C = one trans, two cis D = three cis.

Table II. The Homogeneous Hydrogenation of Methyl Linolenate (4 g) in the Presence of 0.65 mmol [ML2C12] and 5.7 mmol SnCl2 in a Mixture of Benzene (30 mL) and Methanol (20 mL) at 90°C Under 40 atm of...

Table III. The Homogeneous Hydrogenation of Methyl Linolenate in the Presence of 0.33 mmol [ML2C12] and 2.9 mmol...

Methyl Linolenate None Platinum Palladium Methyl Linolenate None P(n-C8H17)j PPh3 + Methyl Linoleate (Mixture 40 40 40 1) 40 mi i... 

Figure 10. The inactivation and cross-linking of RNase A by ethyl arachidonate and methyl linolenate (26)...

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