The fatty acids of degras

Pelick, Nicholas; Shigley, J. W.

doi:10.1007/bf02558169

Cited by 14 publications

(7 citation statements)

References 15 publications

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“…By using commercial standards and previous GC results (4-6), we tentatively identified the iso-and anteiso-branched and normal FAME with chain length 8 to 31 as shown in Figure 1b. Our results confirmed Pelick and Shigley's observation that "iso-compounds almost always give a smaller peak in company with the normal even carbon acids whereas the anteiso-compounds show just the opposite in company with the odd carbon acids" (4). Small peaks eluting about 0.1 min before ante-C 15 , ante-C 17 , and ante-C 19 (Figure 1b) were the corresponding odd iso-FAME (6).…”

Section: Resultssupporting

confidence: 89%

Isolation and melting properties of branched‐chain esters from lanolin

Yao

Hammond

2006

J Americ Oil Chem Soc

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Saturated branched FA and their derivatives are both biodegradable and stable to oxidation. Their m.p. are expected to be enough lower than their straight-chain counterparts to make them ideal as biolubricants. But physical property data for branched fatty esters are limited. In this study, a complex mixture of branched methyl esters was obtained from lanolin through saponification, extraction of unsaponifiables, and methylation. Hydroxy compounds were removed by chromatography on alumina. Vacuum spinning-band distillation separated the mixture roughly by chain length. Countercurrent urea complex formation and low-temperature crystallization separated even-chain isoand odd-chain anteiso-methyl esters of chain lengths 14 through 18 at >95% purity. Transesterification was used to convert methyl esters to isopropyl esters. The m.p. and heat of fusion of each ester were determined by DSC.NMR was used to verify the structure of branched esters.Paper no. J11207 in JAOCS 83, 547-552 (June 2006). KEY WORDS:Branched-chain fatty acid, differential scanning calorimetry, isopropyl ester, lanolin, melting point, methyl ester, nuclear magnetic resonance, urea.There is growing interest in using the derivatives of iso-and anteiso-methyl-branched FA in lubricants and industrial fluids to replace petroleum-based products. Methyl esters (ME) of normal saturated FA are biodegradable and have excellent oxidative stability, but their m.p. are too high for many applications. The m.p. of FA are affected by chain length, molecular structure, and polymorphism. Branches on the carbon chain prevent close chain packing and greatly lower the m.p. Thus, utilization of branched FA can expand the use of stable saturated FA in biodiesel and biolubricants. The m.p. of some branched FFA were reported by Weitkamp in 1945 (1), but melting data for the branched fatty esters are limited.Branched FA occur widely in nature in bacteria, wool wax, and animal surface fats. The most common types of branched acids are the iso-acids, usually with an even number of total carbon atoms, and the anteiso-acids, usually with an odd number of carbon atoms (Scheme 1). They usually are present as minor constituents in complex lipid mixtures, so available sources of branched FA are quite limited. Other researchers at Iowa State University are exploring the expression of these branched FA in oilseed crops. In our study, pure individual branched fatty esters were isolated from lanolin, and their m.p. and heats of fusion were determined. EXPERIMENTAL PROCEDURESPreparation of lanolin ME. Saponification of lanolin (SigmaAldrich Inc., St. Louis, MO) and extraction of unsaponifiables followed the procedure of Barnes et al. (2). To get good separation of unsaponifiables, it was important to adjust for the saponification value of the particular batch of lanolin so that the residual sodium hydroxide concentration was correct according to the phase diagram of Barnes et al. (2). Unsaponifiables were removed by seven or more extractions with heptane at 70°C. Ethanol evaporation was ...

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Section: Resultssupporting

confidence: 89%

Isolation and melting properties of branched‐chain esters from lanolin

Yao

Hammond

2006

J Americ Oil Chem Soc

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“…The wax is principally a mixture of cholesterol, lanosterol, fatty acids (e.g. palmitic and isostearic acids) and hydroxy fatty acids (Gillespie, 1948;Downing et al, 1960;Pelick & Shigley, 1967). Suint contains diverse water-soluble compounds, such as electrolytes (e.g.…”

Section: Introductionmentioning

confidence: 99%

The role of bacterial odours in oviposition by Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae), the Australian sheep blowfly

Emmens

Murray

1982

Bull. Entomol. Res.

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Extracts from cultures of Pseudomonas aeruginosa, Bacillus subtilis, Proteus mirabilis and Enterobacter cloacae in samples of fleeces from sheep were incorporated into nutrient agar and exposed to females of Lucilia cuprina (Wied.) in cages. The blowflies often laid eggs in response to the odours emanating from the cultures of all bacteria. Pseudomonas aeruginosa and E. cloacae did not appear to utilise fleece components in the production of oviposition stimulants, whereas B. subtilis did, utilising compounds such as palmitic acid, and Proteus mirabilis degraded wool fibres to produce sulphurous compounds. The results are discussed in relation to the role of L. cuprina in cutaneous myiasis of sheep.

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“…The separated components may then be characterized and quantitated. Wax esters, either in the intact wax or as a separate fraction, can be cleaved with methanol-acid to give methyl esters and free alcohols (109)(110)(111)(112)113,114,(115)(116)(117) or saponified to give the free acid or salt and alcohol (118). The alcohols may be silylated (116,117), acetylated (111,112,115,117) or trifluoroacetylated (109) and determined by GLC or separated from the other wax components by thin-layer or column chromatography prior to derivatization.…”

Section: Waxesmentioning

confidence: 99%

“…The alcohols may be silylated (116,117), acetylated (111,112,115,117) or trifluoroacetylated (109) and determined by GLC or separated from the other wax components by thin-layer or column chromatography prior to derivatization. After saponification the free acids or salts are usually converted to methyl esters before GLC (113,114,115,117).…”

Section: Waxesmentioning

confidence: 99%

Derivative Formation in the Chromatographic Analysis of Food Additives

Conacher

Page

1979

Journal of Chromatographic Science

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The use of derivatization in the analysis of food additivies by chromatographic means has been reviewed. The large majority of these derivatization techniques are employed to facilitate the gas-liquid chromatographic quantitation of various food additives. Silylation, alkylation, acylation, as well as transesterification, saponification, and chemical decomposition techniques are discussed. The review includes procedures for the analysis of emulsifiers and stabilizers, artificial sweeteners, antioxidants, preservatives, gums, and waxes, and draws in part, from work conducted in the authors' laboratory.

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The fatty acids of degras

Cited by 14 publications

References 15 publications

Isolation and melting properties of branched‐chain esters from lanolin

Isolation and melting properties of branched‐chain esters from lanolin

The role of bacterial odours in oviposition by Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae), the Australian sheep blowfly

Derivative Formation in the Chromatographic Analysis of Food Additives

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