共查询到20条相似文献,搜索用时 31 毫秒
1.
Steven C. Cermak Alex L. Skender Amy B. Deppe Terry A. Isbell 《Journal of the American Oil Chemists' Society》2007,84(5):449-456
Tallow-oleic estolide 2-ethylhexyl (2-EH) esters were synthesized in a perchloric acid catalyzed one-pot process from industrial
90% oleic and tallow fatty acids at various ratios, while varying the ratio of tallow and oleic fatty acids, with the esterification
process incorporated into an in situ second step to provide a functional fluid. Their viscosities ranged 57–80 cSt at 40 °C
and 10.8–14.0 cSt at 100 °C with viscosity index (VI) 169–185. The 100% tallow estolide 2-EH ester had modest low-temperature
properties (pour point = −15 °C and cloud point = −14 °C), while the 50:50 mixture of oleic and tallow fatty acids produced
an estolide that had better low-temperature properties (pour point = −21 °C and cloud point = −21 °C) without a large negative
effect on the oxidative stability. The oxidative stability increased as the amount of saturation increased (rotating pressurized
vessel oxidation test (RPVOT) × 165–274 min). The tallow-oleic estolide 2-EH esters have shown remarkably low evaporative
losses of only 1% loss compared to a 15–17% loss for commercial materials of similar viscosity grade. Along with expected
good biodegradability, these tallow-oleic estolide 2-EH esters had acceptable properties that should provide a specialty niche.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also
be suitable. 相似文献
2.
Steven C. Cermak Jakob W. Bredsguard Billee L. John Kristy Kirk Travis Thompson Katelyn N. Isbell Kati A. Feken Terry A. Isbell Rex Murray 《Journal of the American Oil Chemists' Society》2013,90(12):1895-1902
Acetic‐ and butyric‐capped oleic estolide 2‐ethylhexyl (2‐EH) esters were synthesized in a perchloric acid catalyzed (0.05 equiv) one‐pot process from industrial 90 % oleic acid and either acetic or butyric fatty acids at two different ratios. This was directly followed by the esterification process incorporated into an in‐situ second step to provide a low viscosity estolide ester functional fluid. The monoestolide and polyestolides were separated via vacuum distillation (6–13 Pa) at 240–250 °C. The physical properties of these materials were followed throughout the synthetic process and are reported. The final low viscosity acetic‐ and butyric‐capped monoestolide 2‐EH esters had viscosities of 19.9 and 24.2 cSt at 40 °C and 4.8 and 5.5 cSt at 100 °C with viscosity indexes (VI) of 161 and 163, respectively. Both monoestolide esters displayed excellent pour points (PPs). The PPs of the two were as follows: acetic‐capped estolide 2‐EH ester PP = ?45 °C and butyric‐capped estolide 2‐EH ester PP = ?27 °C. The biodegradable short‐capped oleic estolide 2‐EH esters had excellent low temperature properties and should perform well in low viscosity applications. 相似文献
3.
Synthesis of estolides from oleic and saturated fatty acids 总被引:4,自引:4,他引:0
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. 相似文献
4.
Terry A. Isbell Benjamin A. Lowery Steven C. Cermak 《Journal of the American Oil Chemists' Society》2020,97(4):425-435
Polyethylene glycol (PEG) diesters from estolides of oleic acid, ricinoleic acid, and 12-hydroxy stearic acid were used up to 5 wt% additive in petroleum-derived base oils: 100 N, 220 N, 600 N, PAO 2cSt, PAO 4cst, and PAO 8cSt. The viscosity indices of the petroleum base oils were the lowest (VI = 104–108); the polyalpholefin (PAO) synthetic petroleum-derived base oils were better (VI = 124–136) and the vegetable-derived oils were the best (VI = 111–205). 12-Hydroxystearic estolide PEG 400 diester gave the largest increase in viscosity index in 5% w/w admixtures with PAO 2cSt, 4cSt, 220 N, and 600 N base oils with a 12.3–16.3% increase in viscosity index. Single fatty chain esters had the least impact on viscosity index. As the molecule bulk increased, the viscosity index also increased. This viscosity index effect was demonstrated for the series of monomer to oleic estolide to oleic estolide PEG-200 diester, which gave viscosity indices of 110, 111–122, respectively, in 5% admixtures with 100 N base oil. The larger the size of the molecule coupled with the polar PEG moiety gave the largest impact on viscosity index improvement where a 5 wt% admixture of 12-hydroxystearate estolide PEG-200 diester gave a 25.8% increase in 100 °C viscosity in PAO 2cSt. Incorporation of a dihydroxyl moiety into the molecule at a central side chain location in laurate-capped ricinoleate estolide PEG-200 diester did not increase viscosity index of the base oil but greatly reduced its solubility to less than 0.5 wt%. 相似文献
5.
Steven C. Cermak Girma Biresaw Terry A. Isbell 《Journal of the American Oil Chemists' Society》2008,85(9):879-885
The rotating pressurized vessel oxidation test (RPVOT) was used in the analysis and determination of a new oxidative stability
package (OSP) for a series of estolide based materials. Three antioxidants (BHT, two different alkylated diphenyl amines)
were used in either 0.5 or 1.0 wt/wt%, in different ratios, and in conjunction with one another (hindered phenol/alkylated
diphenyl amines or hindered phenol/mixed alkylated diphenyl amines). The estolide-based samples analyzed for their resistance
to oxidation were two pure (distilled) estolides (oleic estolide 2-EH esters and coco-oleic estolide 2-EH esters), an estolide
mixture that was analyzed straight from the reaction (coco-oleic estolide 2-EH esters with coco 2-EH esters) and finally the
ester fraction from the estolide mixture (coco 2-EH esters). The coco estolide mixture and coco 2-EH esters had the best overall
RPVOT times with 1.0% of the alkylated diphenyl amine, coco estolide mixture, 326 min, and coco 2-EH esters, 310 min. Coco
estolides were expected to have an advantage over the simple oleic estolides due to the increase in saturation in the estolide.
Unexpectedly, the two distilled estolides (oleic and coco) had very similar RPVOT max times with all the antioxidants, and
were much higher than the other oxidative packages tested to date. In general, the alkylated diphenyl amine outperformed mixed
alkylated diphenyl amines in the majority of the individual samples tested specially the coco 2-EH esters and distilled coco-oleic
estolide 2-EH esters material at 1% OSP. Overall, a series of new antioxidants were tested and compared to other commercial
products. A variety of physical properties of the four estolide based material were collected and compared to commercially
acceptable material. Coco-oleic estolide 2-EH esters were formulated to have excellent pour points (−36 °C), were both oxidatively
and hydrolytically stable (RPVOT, 310 min), with expected good biodegradability which should help commercialization.
Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard
of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also
be suitable. 相似文献
6.
Terry A. Isbell Benjamin A. Lowery Karl Vermillion Steven C. Cermak 《Journal of the American Oil Chemists' Society》2020,97(4):409-423
Estolides from oleic acid, 12-hydroxystearic acid, and methyl ricinoleate were synthesized and converted to polyethylene glycol (PEG) diesters. Oleic estolide was synthesized from oleic acid as a homo-oligomeric material using perchloric acid in 68.8% yield and an estolide number (EN) value of 1.29. Estolides from 12-hydroxystearic acid were homo-oligomers made by heating under vacuum at 150 °C for 24 hours to give a quantitative yield of estolide with an EN value of 2.55. Oleic acid-based estolides and 12-hydroxystearic acid-based estolide were esterified with PEG-200 diol to form PEG 200 diesters. Ricinoleate estolides was capped with lauric acid or 12-hydroxystearic estolide by reacting methyl ricinoleate with the corresponding fatty acids at 150 °C using tin(II) octoate as a catalyst. The corresponding estolides were transesterified with PEG-200 diol to form the diesters. The residual olefin of ricinoleate was then epoxidized and underwent ring opening hydrolysis to form the corresponding diol. NMR spectroscopy (1H, 13C, distortionless enhancement by polarization transfer, heteronuclear single quantum correlation, heteronuclear multiple bond correlation, and correlated spectroscopy) was used to characterize the products. 相似文献
7.
Terry A. Isbell Steven C. Cermak 《Journal of the American Oil Chemists' Society》2002,79(12):1227-1233
Triglyceride (TG) estolides were synthesized from the hydroxy moieties of lesquerella and castor oils with oleic acid. Complete
esterification of the hydroxy oils was possible when a slight excess of oleic acid was employed (1 to 1.5 mole equivalents).
The estolides could be formed in the absence of catalyst at 175 to 250°C under vacuum or a nitrogen atmosphere. The optimal
reaction conditions were found to be under vacuum at 200°C for 12 h for lesquerella and 24 h for castor oil. The lesquerella
esterification reaction was completed in half the time of the for castor and with lower equivalents of oleic acid due to the
difunctional hydroxy nature of lesquerella TG compared to the trifunctional nature of castor TG. Interesterification or dehydration
of the resulting estolides to conjugated FA was not a significant side reaction, with only a slight amount of dehydration
occurring at the highest temperature studied, 250°C. Use of a mineral-or Lewis-acid catalyst increased the rate of TG-estolide
formation at 75°C but resulted in the formation of a dark oil, and the reaction did not go to completion in 24 h. Estolide
numbers (i.e., degree of estolide formation) for the reaction and characterization of the products were made by 1H NMR and 13C NMR. The decrease in the hydroxy methine signal at 3.55 ppm was used to quantify the degree of esterification by comparing
this integral to the integral of the alpha methylene protons on the glycerine at 4.28 and 4.13 ppm. 相似文献
8.
A study has been made of the rate of formation of estolides from castor oil fatty acids and of their decomposition at different
temps. Estolide formation appears to be optimum at the end of 5 hr at about 220C, beyond which estolides start decomposing,
giving rise to DCO fatty acids. At about 300C, estolide decomposition is complete within an hour.
During estolide formation there is a linear increase in optical rotation which again decreases linearly, although at a different
rate, during estolide decomposition. At optimum estolide formation, the optical rotation is as high as 25.5.
Part of the thesis submitted by S. N. Modak to the University of Bombay for the degree of Ph.D. 相似文献
9.
Improving the low-temperature properties of alternative diesel fuels: Vegetable oil-derived methyl esters 总被引:14,自引:0,他引:14
R. O. Dunn M. W. Shockley M. O. Bagby 《Journal of the American Oil Chemists' Society》1996,73(12):1719-1728
This work explores near-term approaches for improving the low-temperature properties of triglyceride oil-derived fuels for
direct-injection compression-ignition (diesel) engines. Methyl esters from transesterified soybean oil were evaluated as a
neat fuel and in blends with petroleum middle distillates. Winterization showed that the cloud point (CP) of methyl soyate
may be reduced to −16°C. Twelve cold-flow additives marketed for distillates were tested by standard petroleum methodologies,
including CP, pour point (PP), kinematic viscosity, cold filter plugging point (CFPP), and low-temperature flow test (LTFT).
Results showed that additive treatment significantly improves the PP of distillate/methyl ester blends; however, additives
do not greatly affect CP or viscosity. Both CFPP and LTFT were nearly linear functions of CP, a result that compares well
with earlier studies with untreated distillate/methyl ester blends. In particular, additives proved capable of reducing LTFT
of neart methyl esters by 5–6°C. This work supports earlier research on the low-temperature properties; that is, approaches
for improving the cold flow of methyl ester-based diesel fuels should continue to focus on reducing CP. 相似文献
10.
Selim M. Erhan Robert Kleiman Terry A. Isbell 《Journal of the American Oil Chemists' Society》1995,72(6):671-674
Estolides are formed when the carboxylic acid group of one fatty acid forms an ester link at the site of unsaturation of another
fatty acid. These compounds have the potential to be used in a variety of applications, such as lubricants, greases, plastics,
inks, cosmetics, and surfactants. By manipulating the reaction equilibrium, yields of 20% estolide in clay-catalyzed estolide
reactions have been increased to 30%. Reactions conducted at 180°C, where water was vented out of the reactor at specific
times, not only gave dimer-free estolides but also yields up to 30%. Steam has also been used instead of water with similar
results. Estolides were quite stable at temperatures up to 250°C, even when they were exposed to air. 相似文献
11.
Lucas J. Stolp Patrick J. Gronlund Dharma R. Kodali 《Journal of the American Oil Chemists' Society》2019,96(6):727-738
Fatty acid ester estolides were synthesized from soybean oil and evaluated for plasticizer functionality in poly(vinyl chloride) (PVC). The plasticization ability of the fatty acid ester estolides depends upon the molecular features such as polarity, molecular weight, and branching. The structure of the fatty acid derivatives was modified at the ester head group with various alcohols and the estolide branch was created at the site of unsaturation. Soy fatty acid esters of methanol, iso-butanol, 2-ethylhexanol, and glycerol were prepared to vary the size and polarity at the ester head group. Estolides of these fatty acid esters were prepared using two synthetic routes. In the first route, the fatty acid ester was condensed with an aliphatic acid at the site of unsaturation in the presence of a strong mineral acid. In the second route, the fatty acid ester double bonds were converted to epoxy groups, which were ring opened and acetylated to form acetate estolides. The first synthetic route resulted in low-average estolide content per fatty acid chain while the second route resulted in a higher estolide content per fatty acid chain. The fatty acid ester estolides compounded with PVC showed good plasticizer properties as evidenced by the rheological properties and reduction in glass transition temperature. The fatty acid ester estolides with a higher estolide content had better plasticizer functionality, comparable to commercial controls. 相似文献
12.
Meadowfoam fatty acids (83% monoenoic fatty acid), reacted with 0.01–0.1 mole equivalents of perchloric acid, gave 33–71% yield of estolide, an oligomeric 2° ester, resulting from self condensation. Equimolar amounts of perchloric acid to fatty acid failed to produce estolide but converted the fatty acids to a mixture of lactones, mainly γ-eicosanolactone. Temperature plays a critical role; higher temperatures (75–100°C), at the same acid concentration, provide lactones while lower temperatures (20–65°C) yield estolides. Lower acid levels (<0.1 mole equivalents) gave the best yields (≈70%) at 65°C. The estolide and monomer were characterized by nuclear magnetic resonance, infrared high-pressure liquid chromatography, gas chromatography, gas chromatography/mass spectrometry. The estolide is a mixture of oligomers with an average distribution near 1.65 ester units. The ester linkages are located mainly at the original double bond positions but have some positional isomerization to adjacent sites in accord with carbocation migration along the alkyl chain. The residual double bond of the estolide was extensively isomerized fromcis totrans and positionally along the chain. The distilled monomer is similar in structure to the unsaturated portion of the estolide with geometrical and positional double bond isomerization. In addition, a significant amount of cyclization of the fatty acids to lactone (≈30%) had occurred. 相似文献
13.
The 20% yields of estolides prepared from oleic acid and meadowfoam oil fatty acids are improved when the montmorillonite
clay catalysts are modified to increase their activity. Changes we explored included acidifying the clay, treating to increase
the surface area of clay to introduce new active sites, and decreasing the ionic character of the clay surface to enhance
adsorption of the fatty acids. We also evaluated the use of higher levels of clay in the reactions. Clays treated with Fe3+ salts increase the estolide yield from 21 to 27%, a 28% increase. Clay catalysts were also treated with surface-active reagents.
The most active were cationic surfactants, and montmorillonite clays treated with cetyltrimethylammonium chloride increased
the estolide yield to 30%. Estolide yields could not be improved beyond 30% by increasing the amount of clay. However, nitrogen
sparging increases the efficiency of stirring and increased the estolide yield to 35% estolide. 相似文献
14.
Shehu Isah Jainwei Zhang Girma Biresaw Gary D. Strahan Alberto Nunez Victor T. Wyatt Helen Ngo Gulnihal Ozbay 《Journal of the American Oil Chemists' Society》2021,98(6):683-695
Previously synthesized C36-dimer acids (DA) have been esterified (97 ± 0.2% conversion at 120 °C for 72 hours) with 2-ethylhexanol (2-EH) to produce a new class of C52-DA 2-EH esters that have potential application in biolubricant formulations such as base oils and additives. Investigation of physicochemical and lubricant properties showed the bio-based esters have good solubility in commercial base stocks such as polyalpha olefin (PAO-6) (>20 w/w) and high-oleic sunflower oil (HOSuO) (>20 w/w). The neat C52-DA 2-EH esters displayed a three- to eightfold higher kinematic viscosity and comparable viscosity index (VI = 134) as a commercial base stock, PAO-6 (VI =137). Both C52-DA 2-EH esters, whose parent C36-DA were synthesized with two different zeolite catalysts, were oxidatively stable above 176 °C. Blending C52-DA 2-EH esters in HOSuO improved the pour point (PP) of HOSuO from −18.8 to −21.0 °C at 1% w/w and the cloud point (CP) from −6.3 to −10.6 °C at 8% w/w of C52-DA 2-EH ester 1. A similar trend was observed for C52-DA 2-EH ester 2, indicating that the esters possess PP depressant (PPD) characteristics in HOSuO blends. Blending C52-DA 2-EH esters in PAO-6 increased the VI of PAO-6, which is an indication that the bio-based esters were acting as VI improvers (VII). It was concluded that C52-DA 2-EH esters can be employed commercially as bio-based base oils and as PPD and VII additives in lubricant formulations. 相似文献
15.
Steven C. Cermak Jakob W. Bredsguard Robert O. Dunn Travis Thompson Kati A. Feken Katie L. Roth James A. Kenar Terry A. Isbell Rex E. Murray 《Journal of the American Oil Chemists' Society》2014,91(12):2101-2109
A series of 26 different antioxidants and commercial antioxidant packages designed for petroleum‐based materials, containing both natural and synthetic‐based materials, were evaluated with dimeric coconut‐oleic estolide 2‐ethylhexyl ester (2‐EH), a bio‐based material. The different antioxidants were categorized into different classes of phenolic, aminic, and blended/others materials. The oxidation onset temperatures (OT) using non‐isothermal pressurized differential scanning calorimetry (PDSC) were measured and recorded under previously reported standard conditions. The aminic series gave the best resistance to oxidation as defined by the PDSC method with OT of 246.6 and 244.7 °C for the best two performers, which was a 38 °C improvement over the uninhibited or unformulated dimer estolide material. The phenolic series, containing most of the naturally occurring antioxidants, was the least successful formulation package for the dimer estolide. The blended/other materials, which were specifically designed for petroleum‐based lubricants, did not have the best OT, since the estolides and other bio‐based materials interact differently than their petroleum counterparts. A number of potential antioxidants have been identified as useful additives for the estolides esters. The OT of the estolide and formulated materials correlated well with other bio‐based materials such as biodiesel. 相似文献
16.
Igor Marques Cavalcante Natália Rodrigues de Castro Rocha Débora Hellen Almeida de Brito Ana Paula Dantas Schuller João Francisco Câmara Neto Selene Maia de Morais Francisco Murilo Tavares de Luna Maria Telma Gomes Freire Schanz Martin E. Maier Nágila Maria Pontes Silva Ricardo 《Journal of the American Oil Chemists' Society》2019,96(1):75-82
Three novel esters of undecylenic acid (UA) were synthesized using the following polyols: linear diglycerol (DG), pentaerythritol monomethylether (PEME), and trimethyloltoluene (TMT). They were characterized through density, viscosity, thermo-oxidative stability, melting point (m.p.), miscibility with mineral oils, and toxicity to evaluate their potential as ecofriendly lubricants. Trimethylolpropane (TMP) triundecylenate was also synthesized and characterized as a reference ester. Esters’ densities were in the range 0.93–0.97 g cm−3. The PEME ester showed a kinematic viscosity of 25.2 cSt at 40°C, only slightly higher than that of TMP ester (24.7 cSt), both of them near the ISO VG 22 class, while DG and TMT esters were near the ISO VG 32 class, with viscosities of 28.3 and 37.1 cSt, respectively. PEME and TMT esters were similar in thermo-oxidative stability and more stable than their corresponding oleate esters. The m.p. of TMT ester was remarkedly low (−54°C), showing its potential for very cold temperature applications. TMT ester was found to be nontoxic against Artemia salina (LC50 > 1000 μg mL−1), an initial indication of nontoxicity of UA esters in aquatic media. The synthesized esters showed potential to be applied as ecofriendly lubricants. 相似文献
17.
Terry A. Isbell Hans B. Frykman Thomas P. Abbott Joseph É. Lohr Joseph C. Drozd 《Journal of the American Oil Chemists' Society》1997,74(4):473-476
The production of estolide from oleic acid with sulfuric acid as a catalyst was optimized for minimal acid concentration and
temperature. Commercial oleic acid forms estolide optimally when reacted at 55°C with 5% vol/vol concentrated sulfuric acid
for 24 h under vacuum. The extent of oligomerization was 1.2 estolide units under these reaction conditions. Temperature plays
a critical role in the rate of estolide formation as well as in the overall yield, with higher temperatures providing faster
rates but lower yields. The ratio of sulfuric acid to oleic acid equivalents also plays a role, where higher acid concentrations
gave faster rates and higher yields of estolide. Vacuum had a minor effect on oligomerization and estolide yield. 相似文献
18.
Yunzhi Chen Girma Biresaw Steven C. Cermak Terry A. Isbell Helen L. Ngo Li Chen Amber L. Durham 《Journal of the American Oil Chemists' Society》2020,97(3):231-241
Estolides are bio-based oils synthesized from fatty acids or from the reaction of fatty acids with vegetable oils. Estolides have many advantages as lubricant base oils, including excellent biodegradability and cold flow properties. Promising applications for estolides include bio-lubricant base oils and in cosmetics. In this review, the synthesis of estolides from fatty acids using four different types of catalysts, namely, mineral acids, solid acids, lipases, and ionic liquids, is summarized. The summary includes the yield of estolide obtained from varying synthetic conditions (time, temperature, catalyst). Also reviewed are studies comparing the physical properties of estolides synthesized from refined fatty acids against those synthesized from fatty acid mixtures obtained from vegetable oils such as coconut, castor, Physaria, etc. By varying the structure of the fatty acids, estolides with a wide range of pour point, cloud point, and viscosity are synthesized to meet a wide range of application requirements. Currently, estolide products are being commercialized for personal care and lubricant base oils for automotive, industrial, and marine applications. The application areas and the demand for estolides is expected to grow as the drive for switching from petroleum to bio-based products keeps growing. 相似文献
19.
Lucas J. Stolp Eugene Joseph Dharma R. Kodali 《Journal of the American Oil Chemists' Society》2019,96(11):1291-1302
Plasticizers are nonvolatile organic liquids that impart flexibility to polymers. Due to environmental, health, and safety reasons, the industry is looking for bioplasticizers to replace petroleum-derived phthalates. To fulfill this need, soy fatty acid ester estolides were synthesized, characterized, and evaluated as phthalate replacements. Soybean oil was transesterified with methanol or glycerol to form lower molecular weight fatty acid esters that were epoxidized and ring opened with acetic acid and acetylated to give the final products. Ring opening and acetylation of the epoxidized oleic acid esters gave acyclic acetate fatty acid ester estolides, whereas the polyunsaturated fatty acid esters, linoleate, and linolenate gave cyclic tetrahydrofuran derivatives and cross-linked higher molecular weight materials. The cyclization mechanism to form the tetrahydrofuran derivatives was postulated. Soy fatty acid ester estolides were compounded with formulated poly(vinyl chloride), (PVC) and tested for their functional properties. The physical and functional properties of the new bioplasticizers were compared with commercial plasticizers. The elasticity of PVC compounded with experimental plasticizers and commercial phthalates was comparable. PVC compounded with fatty acid methyl ester estolide showed lower glass transition temperature and similar tensile properties compared to PVC compounded with the commercial phthalate. PVC compounded with the glyceryl fatty acid ester estolide showed a higher glass transition temperature, higher tensile properties compared to PVC compounded with the commercial phthalate. 相似文献
20.
Douglas G. Hayes Robert Kleiman 《Journal of the American Oil Chemists' Society》1995,72(11):1309-1316
Eight lipases were screened for their ability to synthesize estolides from a mixture that contained lesquerolic (14-hydroxy-11-eicosenoic)
acid and octadecenoic acid. With the exception ofAspergillus niger lipase, all 1,3-specific enzymes (fromRhizopus arrhizus andRhizomucor miehei lipases) were unable to synthesize estolides.Candida rugosa andGeotrichum lipases catalyzed estolide formation at >40% yield, with >80% of the estolide formed being monoestolide from one lesquerolic
and one octadecenoic acyl group:Pseudomonas sp. lipase synthesized estolides at 62% yield, but the product mixture contained significant amounts of monoestolide with
two lesquerolic acyl groups as well as diestolide. ImmobilizedR. miehei lipase was chosen to catalyze the esterification of mono-and polyestolide, derived synthetically from oleic acid, with fatty
alcohols or α,ω-diols. Yields were >95% for fatty alcohol reactions and >60% for diol reactions. In addition, the estolide
linkage remained intact through the course of the esterification process. Esterification of estolides improved the estolide’s
properties—for example, lower viscosity and higher viscosity index—but slightly raised the melting point. Estolides and, particularly,
estolide esters may be suitable as lubricants or lubricant additives. 相似文献