Diels-Alder adducts from safflower oil fatty acids

Methyl esters of alkali-isomerized safflower oil fatty acids after elaidinization with sulfur were treated with styrene in the presence of hydroquinone, with or without solvents. A combination of column chromatography and gas liquid chromatography techniques was employed for the estimation of the methyl esters of unreacted fatty acids, Diels-Alder adduct and polymers in the reaction products. Maximum yield of the Diels-Alder adduct (26.6%) was obtained when the elaidinized methyl esters of the fatty acids were treated with 1.5 moles of styrene per mole of linoleic acid in safflower oil fatty acids at 200–210 C for 6 hr. The methyl ester of the adduct was isolated in about 90% purity from the reaction product by vacuum distillation followed by solvent fractionation. The butyl ester of the adduct and the epoxy derivative of the methyl ester adduct were prepared and characterized.     

Synthesis of polyoxyethylene derivatives of diesters of sucrose with long-chain fatty acids

Summary Since the long-chain fatty acid sucrose diesters inevitably produced in the synthesis of monoesters are only slightly soluble in water, no important use can be found for them at the present time except as oilsoluble emulsifying agents. In order to exploit new uses we have attempted to improve their solubility in water by introducing oxyethylene radicals into the molecule. The addition reaction of ethylene oxide with the sucrose diesters was carried out in an autoclave in the presence of alkaline catalysts. With the reaction temperature maintained between 100–130° the pressure decreased as the reaction proceeded, and one to two hours were required to consume the ethylene oxide used. The addition products are yellow or orange oily materials soluble in water. Aqueous solutions showed good surface-active properties.     

Methyl glucoside fatty acid diesters

Summary and Conclusion Procedures are described for the preparation of methyl glucoside diesters by direct esterification, using a ratio of one mole of methyl glucoside with two moles of fatty acids. Rate studies indicated that lead or stannous soaps are more effective catalysts than the sodium soaps for speeding up tis esterification. With equal molar quantities of methyl glucoside and fatty acid, the lead and the sodium soap catalysts give products containing predominantly diester and half the methyl glucoside remaining unreacted. Under the same conditions stannous soap catalysis gives high yields of monoesters containing only very small percentages of unreacted methyl glucoside. From the standpoint of speed of reaction, color of the final produets, ease of removal of catalyst from the ester products, and catalyst cost, litharge is the preferred cytalyst for the preparation of methyl glucoside diesters. Properties of various methyl glucoside fatty acid diesters, prepared on a laboratory scale, are given. Du Noüy surface-tension measurements indicate that small quantities of the methyl glucoside dilaurate, dicaprate, or dioleate are quite effective in lowering the surface tension of water.     

Preparation and emulsifying properties of polyethylene glycol (15OO) diesters of fatty acids

Oil soluble polyethylene glycol (PEG-1500) diesters of stearic, 12-hydroxystearic, oleic and 12-hydroxy oleic (ricinoleic) acids were prepared by standard condensation reaction procedure. The surface active/emulsifying properties of the products were evaluated by determining interfacial tension and through performance test in making water-in-oil emulsion. The presence of double bond or hydroxyl group in the C₁₈ acids, PEG content of reacting mixture, and nature and concentration of the catalyst in preparing the emulsifier all were found to have great bearing on the emulsifying property and stability of w/o emulsions, particularly when the aqueous phase contained a significant quantity of ions. Only the first factor, the effect of double bond and/or the hydroxyl group, is discussed in this paper.     

Mass spectra of the picolinyl esters of isomeric mono- and dienoic fatty acids

The picolinyl ester derivatives of the complete series of isomeric octadecenoates, methylene-interrupted octadecadienoates, and of octadec-9-ynoate have been subjected to gas chromatography-mass spectrometry. A fused-silica capillary column, coated with a cross-linked methyl silicone, was used for the separation. Electron impact spectra were determined at 70 eV. Earlier observations with a limited series of model compounds were confirmed, and it was shown that the picolinyl ester derivatives were of almost universal value in the location of double bonds in such isomers. Difficulties of interpretation arose mainly when the double bonds were close to the carboxyl group.     

High performance size exclusion chromatography of fatty acids,mono-, di- and triglyceride mixtures

A high performance size exclusion chromatographic (HPSEC) method is described for the separation and quantitation of fatty acids, mono-, di- and triglyceride mixtures. The various lipid components were separated on two columns packed with 5 μm styrene/divinylbenzene copolymer and connected in series. Toluene was employed as eluant, and components were monitored by refractometry. A formula derived for calculation of total weighted correction factors (WCF) for the various lipid classes based on known values of correction factors of simple lipid components and the fatty acid composition of the sample allowed quantitation of lipid mixtures containing a variety of different molecules. The precision of the experiments is such that the relative standard deviation for each lipid component was 1–5%, and a component could be detected at 0.05% level.     

Diels-alder adducts from safflower fatty acids: III. Acrylic and related acid dienophiles

The Diels-Alder adducts from alkali conjugated and elaidinized safflower fatty acids with acrylic, methacrylic, crotonic and cinnamic acids and their esters as dienophiles were obtained in 40–64% yields. Low yields of 16–18% were obtained when 10-undecenoic acid and its ester were used. Most of the adducts could be estimated quantitatively in the reaction products by column chromatography or gas liquid chromatography (GLC). For the estimation of the adducts from crotonic and 10-undecenoic acids a combination of column chromatography and GLC techniques was employed. Partitioning between hexane and 90% methanol, partial esterification with alkali washing, and splitting and fractional distillation under reduced pressure were methods used to obtain the adducts in 90–95% purity.     

NMR spectra of mercury adducts of unsaturated fatty acids: Quantitative determination ofcis-trans ratio

By stereospecific adduct formation between mercuric acetate and unsaturated fatty acids, derivatives are obtained suitable for NMR determination ofcis-trans ratio. The preparation and optimal experimental conditions are determined. Experimental data are found to be within a few per cent of the true values.     

Reactions of conjugated fatty acids. V. Preparation and properties of diels-alder adducts and their esters fromtrans,trans-conjugated fatty acids derived from soybean oil

Summary Soybean fatty acids were conjugated with alkali, and the contained, conjugated dienoic acids were isomerized with iodine to thetrans,trans configuration. Adducts were prepared from thesetrans,trans-conjugated acids by condensation with maleic anhydride and acrylic acid. The adducts were isolated, purified, and converted to esters by using a variety of alcohols, including methyl, ethyl,n-propyl,n-butyl, and allyl alcohols. Esters made from saturated alcohols were converted into the corresponding epoxy derivatives. All of the esters (except allyl) and all of the epoxy esters were compatible with an equal weight of polyvinyl chloride and appeared to be primary plasticizers for this plastic. The epoxy esters were effective in inhibiting heat deterioration of polyvinyl chloride. Presented at fall meeting. American Oil Chemists' Society, September 23–26, 1956, Chicago, Ill.     

Preferential formation of mono-dimethyl disulfide adducts for determining double bond positions of poly-unsaturated fatty acids

Determination of double bond positions of unsaturated lipids is fundamental for understanding their biofunctions and biosynthetic pathways. Derivatizing unsaturated lipids with dimethyl disulfide (DMDS) represents a convenient method to yield characteristic ions for determining double bond positions. However, DMDS adduction of poly-unsaturated lipids often leads to the formation of poly- and/or cyclized DMDS adducts, which yield complex mass spectra that are difficult to interpret in terms of double bond positions. Here, we report a room-temperature, convenient experimental procedure to preferentially form mono-DMDS adducts for poly-unsaturated fatty acid methyl esters (FAMEs) with two to five double bonds (c9, c12-C_18:2, t9, t12-C_18:2, c5, c9, c12-C_18:3, c7, c10, c13, c16-C_22:4 and c5, c8, c11, c14, c17-C_20:5). Electron-impact ionization mass spectra of these mono-DMDS adducts provide highly diagnostic ions for determining positions of all double bonds. Our approach overcomes the limit of traditional DMDS derivatization methods which are generally limited to mono-unsaturated molecules. In addition, we show gas chromatography and gas chromatography–mass spectrometry analyses of mono-DMDS adducts can also provide useful information about double bond geometry, as cis double bonds are prone to isomerize to trans isomers.     

Preparation of some mono- and diesters of n,n-disubstituted amides and their evaluation as plasticizers

Mono- and diesters of fatty acid- and aromatic acid-derived N,N-disubstituted amides were prepared in which the acid moieties were alternately substituted to function as the basic amide moiety or the terminal ester moiety. Several of the esteramides were evaluated as plasticizers for polyvinyl chloride (PVC). The plasticized stocks exhibited properties that equaled, and in some instances were superior to PVC plasticized with the common plasticizer, di-2-ethylhexyl phthalate (DOP). The monoesters were more compatible than the diesters. Thermal stability was enhanced by the presence of the benzoic acid moiety in the molecule. Brittle point temperatures were shown to be a predictable characteristic for specific terminal groups, based on structural similarity of the basic molecule.     

Diels-alder adducts from safflower oil fatty acids: I. Maleic anhydride as dienophile

The Diels-Alder reaction between alkali conjugated and elaidinized safflower oil fatty acids and maleic anhydride was studied under various experimental conditions. The principal product which was obtained in 51–55% yields was a mixture of the adduct of maleic anhydride and maleic acid in 40∶60 proportions. The isolation and properties of this mixed adducts from the reaction mixture and their conversion to trimethyl, tributyl and triallyl esters are described. The trimethyl ester was also obtained in good yield from the methyl esters of the fatty acids and dimethyl maleate.     

A general method for the chromatographic analysis of mono-, di-, and triglycerides and the mono- and diesters of ethylene glycol and polyethylene glycol

Summary A procedure for the chromatographic separation and determination of the ester mixtures of glycerin, ethylene glycol, and polyethylene glycol is presented. The adsorbent is silea gel, and the mobile phase is a series of solvents with increasing polarity. A procedure for quantitative determination of small amounts of monoglyceride present in a glyceryl ester mixture is presented. A solvent system different from that used for glyceryl and ethylene glycol ester mixtures was developed for ester mixtures of polyethylene glycols. The esters of polyethylene glycols with average molecular weights of 300–600 were shown to give the same chromatogram.     

Urea complexation for the rapid, ecologically responsible fractionation of fatty acids from seed oil

Urea complex formation is a classic method for fractionating fatty acids from seed and other oils. The method’s simplicity, ease of scaling, and ecological friendliness suggest its reevaluation in regard to modern fractionation challenges. In keeping with this, a simple, quick, inexpensive, robust, and environmentally friendly procedure was developed for reducing the saturated free fatty acid (FFA) content of saponified low-erucic acid rapeseed oil (LEAR). The process involves formation of a homogeneous 65°C solution of FFA and urea in 95% ethanol (5% water), followed by cooling of the resultant urea complex slurry to room temperature. The urea complex and liquid phases are separated by gravity filtration, and the urea isolated in each phase is removed by extraction with 60°C water. Saturated LEAR oil FFA preferentially formed urea complexes easily separated from the noncomplexed, mostly unsaturated FFA, the main product of interest. The effects of single- vs. double-stage fractionations and several other variables (component mass or volume ratios, temperature, ethanol solvent to water ratio) were preliminarily evaluated. Results demonstrated the robustness, reproducibility, and simplicity of the method.     

Fatty acids of the alkane diol diesters of vernix caseosa

The fatty acid monoenes esterified to the alkane diol diesters of vernix caseosa lipid form two patterns of homologues starting from either C₁₆Δ9 or C₁₆Δ6 and adding (or subtracting) an integral number of C₂ units at the carboxyl group. Although components of the Δ6 pattern are the predominant monoenes of sebaceous gland ester lipid classes, for these diol diesters Δ9 pattern components are preferentially used.     

Metabolism of odd-numbered fatty acids and even-numbered fatty acids in mouse

Fatty acids are converted into energy via beta-oxidation. Although almost all natural occurring fatty acids are even-numbered, there are some odd-numbered fatty acids too. The details of the metabolism rate of odd-numbered fatty acids, however, are not clear. In the present study, we simultaneously administered a triacylglycerol containing four types of labeled even-numbered (palmitic acid and stearic acid) and odd-numbered (pentadecanoic acid and heptadecanoic acid) fatty acids to mice to compare the rates of their metabolism. The rates of metabolism were evaluated based on the accumulation of the labeled fatty acids in the small intestine epithelium, liver, and epididymal fat. Odd-numbered fatty acids accumulated mainly in the epididymal fat. In contrast, there was no accumulation of even-numbered fatty acids observed in the small intestine epithelium, liver, or epididymal fat. These results suggest that odd-numbered fatty acids might not be favorable substrates for beta-oxidation-related enzymes.     

Identification of conjugated fatty acids by gas chromatography-mass spectrometry of 4-methyl-1,2,4-triazoline-3,5-dione adducts

4-Methyl-1,2,4-triazoline-3,5-dione was reacted with conjugated fatty acid methyl esters to form Diels-Alder cycloaddition products. The electron impact mass spectra of conjugated octadecadienoates and 9,11,13-octadecatrienoate were simple and informative and allowed the positions of the double bonds to be determined. The dienes gave single adducts whereas the triene formed four products that corresponded to two stereoisomers of the adducts of the 9,11-diene system and two of the 11,13-diene system. The method can be used to complement other methods for identifying conjugated fatty acids.     

High performance liquid chromatography analyses of emulsifiers: I. Quantitative determinations of mono- and diacylglycerols of saturated fatty acids

A high performance liquid chromatography (HPLC) method is described for the separation of mono-, di-, and triacylglycerols of fatty acids on a 25-cm column packed with 10 μm LiChrosorb DIOL. The acylglycerols are eluted isocratically with isooctane-isopropanol (95:5) within 10 min, and the components monitored by UV-absorption at 213 nm. The applicability of the method for the quantitative determination of the mono- and diacylglycerol content of fully hardened monoglycerides using an internal standard method has been demonstrated. The method shows excellent reproducibility and accuracy with standard deviations of a distilled monoglyceride containing 92.1% monoacylglycerols and 6.5% diacylglycerols of 0.70% and 0.42%, respectively. The method is applicable to other types of emulsifiers, for instance, acetylated monoglyceride emulsifiers and propylene glycol esters of fatty acids.