Studies in estolides. I. Kinetics of estolide formation and decomposition

Modak, Sudipta; Kane, J. G.

doi:10.1007/bf02635584

Cited by 34 publications

(36 citation statements)

References 9 publications

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“…Parameters for method A were: column flow 3.3 mL/min with helium head pressure of 15 psi; split ratio 22 HPLC. Reversed-phase HPLC analyses were performed on a Thermo Separations Spectra System AS1000 autosampler/ injector (Fremont, CA) with a P2000 binary gradient pump from Thermo Separation Products coupled to a Alltech ELSD 500 evaporative light-scattering detector (ELSD).…”

Section: Methodsmentioning

confidence: 99%

“…Estolides and estolide esters from meadowfoam (3,19,20), oleic acid (21), castor oil, or any source of hydroxy fatty acids (22,23) have shown promise as cosmetics, coatings, and biodegradable lubricants. Estolides and estolide esters compare favorably to commercially available industrial products such as petroleum-based hydraulic fluids, soy-based fluids, and petroleum oils, and usually outperform the competition (5).…”

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confidence: 99%

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Synthesis of estolides from oleic and saturated fatty acids

Cermak

Isbell

2001

J Americ Oil Chem Soc

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Oleic acid and various saturated fatty acids, butyric through stearic, were treated with 0.4 equivalents of perchloric acid at either 45 or 55°C to produce complex estolides. Yields varied between 45 and 65% after Kugelrohr distillation. The estolide number (EN), i.e., the average number of fatty acid units added to a base fatty acid, varied as a function of temperature and saturated fatty acid. The shorter-chain saturated fatty acids, i.e., butyric and hexanoic, provided material with higher degrees of oligomerization (EN = 3.31) than stearic acid (EN = 1.36). The individual, saturated fatty acid estolides each have very different characteristics, such as color and type of by-products. The higher-temperature reactions occurred at faster rates at the expense of yield, and lactones were the predominant side products. At 55°C, lactone yields increased, but the δ-γ-lactone ratio decreased; this led to lower estolide yields. The opposite trend was observed for the 45°C reaction. The saturate-capped, oleic estolides were then esterified with 2-ethylhexyl alcohol, and the chemical composition of these new estolides remained consistent throughout the course of the reaction.Paper no. J9799 in JAOCS 78, 557-565 (June 2001).Estolides are a class of esters, based on vegetable oils (1-4), that form when the carboxylic acid functionality of one fatty acid reacts at the site of unsaturation of another fatty acid to form an ester linkage. These linkages are used to help characterize the structure of the estolide since the estolide number (EN) is defined as the average number of fatty acids added to a base fatty acid (Scheme 1, EN = n + 1). The secondary ester linkages of the estolide are more resistant to hydrolysis than those of triglycerides, and the unique structure of the estolide results in materials that have far superior physical properties for certain applications than vegetable and mineral oils (5). Estolides have been found in nature (6,7) and have been synthesized (1-4,8) in the laboratory. Isbell and Kleiman (9) synthesized estolides from oleic fatty acids and found them to have interesting chemical behavior. The double bond in oleic acid is located at the 9 position which, under the correct conditions of acid concentration, reaction time, and temperature, undergoes estolide formation with minimal migration. The proposed mechanism involves formation of a carbocation that can undergo nucleophilic addition with or without carbocation migration along the length of the chain. If the migration continues to the C4 and C5 position, the fatty acid will cyclize to form lactones, the major side product to estolide formation (Scheme 2) (10-15).Lactones are formed from an intramolecular cyclization of a fatty acid carboxyl group with a carbocation located at the 4-or 5-position on a fatty acid backbone. Under the correct conditions, Showell et al. (13) and Cermak and Isbell (14,15) were able to produce γ-and δ-lactones, respectively. A major side product in the estolide synthesis, lactones are an interesting class of compounds...

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Synthesis of estolides from oleic and saturated fatty acids

Cermak

Isbell

2001

J Americ Oil Chem Soc

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“…Estolides and estolide esters of oleic acid [19,21,24,143,144,146,147], meadowfoam oil [23,143], castor oil [148][149][150][151][152], or any source of monoenoic FAs or HFAs [148,152] show promise as biolubricants. Isbell et al [143] have compared a series of estolides and estolide esters from oleic, meadowfoam and Crambe FAs (see Table 6.10).…”

Section: Estolide Ester Base Stocksmentioning

confidence: 99%

Chemical transformations of renewable lubricant feedstocks

Bart¹,

Gucciardi²,

Cavallaro³

2013

Biolubricants

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“…Another approach to prepare estolides was through the esterification reaction between plant oil that contains hydroxyl groups on its triglyceride molecule such as castor oil and a fatty acid such as oleic acid (Isbell et al, 2002). In addtion, estolides can also be produced by intermolecular esterification of hydroxy fatty acid such as ricinoleic acid at 200°C (Modak et al, 1965).…”

Section: Introductionmentioning

confidence: 99%

Non-Catalytic One-Pot Synthesis of Polyhydroxy Estolides From Oleic Acid

Hoong¹

2017

JOPR

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Polyhydroxy estolides were successfully synthesised from oleic acid through a non-catalytic one-pot method. Gel permeation chromatography (GPC) analysis showed that the yield of the polyhydroxy estolides was about 72% and the number average molecular weight (M n ) of the product ranges between 1000 -2200 Da. Other instrumental analyses such as nuclear magnetic resonance (NMR), Fourier transform infra- Red (FTIR) and Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) as well as acid value analysis revealed that the prepared polyhydroxy estolides was oligomers of dihydroxystearic acidlinked by ester groups and further confirmation of the oligomers structure was achieved by reduction and saponification reactions.

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Studies in estolides. I. Kinetics of estolide formation and decomposition

Cited by 34 publications

References 9 publications

Synthesis of estolides from oleic and saturated fatty acids

Synthesis of estolides from oleic and saturated fatty acids

Chemical transformations of renewable lubricant feedstocks

Non-Catalytic One-Pot Synthesis of Polyhydroxy Estolides From Oleic Acid

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