Synthesis of wax esters for use as possible sperm oil replacements

In efforts to prepare wax esters chemically similar to those comprising sperm oil, selected fats or blends thereof were reduced to alcohols which then were reacted with the initial triglycerides to get such wax esters. For instance, lard oil was reduced to lard oil alcohol in the presence of sodium and methyl isobutyl carbinol in xylene. Most of the resulting sodium alcoholates (95–98%) were decomposed with urea, and subsequent addition of lard oil (triglycerides) resulted in rapid formation of the desired wax esters in ca. 80–90% yields. In preliminary studies, the same wax esters were prepared by a more circuitous route. The alcoholates were decomposed completely with urea, the fatty alcohols were liberated, and they then were esterified with free lard oil acids. Similarly treated were a blend of lard, coconut and crambe oils, fractionated tallow, and a commercial grade oleic acid. Presented at the AOCS Meeting, New Orleans, April 1973. ARS, USDA.     

Lipase-catalyzed alcoholysis of crambe oil and camelina oil for the preparation of long-chain esters

Crambe oil and camelina oil were transesterified with oleyl alcohol, the alcohols derived from crambe and camelina oils, n-octanol or isopropanol using Novozym 435 (immobilized lipase B from Candida antarctica), Lipozyme IM (immobilized lipase from Rhizomucor miehei), and papaya (Carica papaya) latex lipase as biocatalysts. The highest conversions to alkyl esters were obtained with Novozym 435 (up to 95%) in most cases, whereas Lipozyme IM and papaya latex lipase gave lower (40 to 50%) conversions. The conversions with long-chain alcohols (oleyl alcohol, crambe alcohols, and camelina alcohols) were higher (40 to 95%) than with medium-chain n-octanol (30 to 85%). Isopropyl esters of crambe oil and camelina oil were obtained with rather low conversions using Novozym 435 (<40%) and Lipozyme IM (about 10%) as biocatalysts, whereas with papaya latex lipase no isopropyl esters were formed. The conversions of crambe oil and camelina oil to oleyl and n-octyl esters using Novozym 435 as biocatalyst were hardly affected by the ratio of the substrates, but with Lipozyme IM the conversions to alkyl esters distinctly increased with an excess of alcohol substrate Presented as part of the doctoral thesis of Georg Steinke to the University of Münster, Münster, Germany     

Alkali-catalyzed alcoholysis of crambe oil and camelina oil for the preparation of long-chain esters

The alcoholysis of crambe and camelina oils was carried out with oleyl alcohol, alcohols derived from crambe and camelina oils, and n-octanol using potassium hydroxide as catalyst to prepare alkyl esters. Conversions to alkyl esters were about 0% with oleyl alcohol, 20–45% with crambe and camelina alcohols, and 60% with n-octanol. The conversion to esters for crambe and camelina oil with oleyl alcohol and n-octanol increased with increasing molar excess of alcohol. Composition of the alkyl esters formed was as expected from the composition of the reaction partners. Presented as part of the doctoral thesis of Georg Steinke to the University of Münster, Münster, Germany.     

Effect of n−3 fatty acids on the key enzymes involved in cholesterol and triglyceride turnover in rat liver

The effect of long-chain n−3 fatty acids on hepatic key enzymes of cholesterol metabolism and triglyceride biosynthesis was investigated in two rat models. In the first model, rats were intravenously infused for two weeks with a fat emulsion containing 20% of triglycerides in which either n−6 or n−3 fatty acids predominated. The treatment with n−3 fatty acids led to a reduction primarily of serum cholesterol (45%), but also of serum triglycerides (18%). HMG-CoA reductase activity and cholesterol 7α-hydroxylase activity were reduced by 45% and 36%, respectively. There were no significant effects on diacylglycerol acyltransferase (DGAT) or phosphatidate phosphohydrolase (PAP) activities. In the second model, rats were fed a diet enriched with sucrose, coconut oil and either sunflower oil (n−6 fatty acids) or fish oil (long-chain n−3 fatty acid ethyl esters). The treatment with n−3 fatty acids decreased serum triglycerides (41%) and, to a lesser extent, serum cholesterol (17%). Neither glycerol 3-phosphate acyltransferase (GPAT) or DGAT were affected by n−3 fatty acids. In contrast, PAP activity was reduced by 26%. HMG-CoA reductase was not significantly affected, whereas cholesterol 7α-hydroxylase activity was reduced by 36%. The results indicate that part of the TG-lowering effect of long-chain n−3 fatty acids may be mediated by inhibition of the soluble phosphatidate phosphohydrolase. The effect on serum cholesterol may be partly due to inhibition of HMG-CoA reductase.     

Chemical structure of long-chain esters from “sansa” olive oil

The major objective of this study was to determine the chemical structure of long-chain esters present in lower-grade olive oil. The classes of esters composing the hexanediethyl ether (99∶1) extract of the wax fraction from a pomace olive oil were: (i) esters of oleic acid with C₁−C₆ alcohols, (ii) esters of oleic acid with long-chain aliphatic alcohols in the range C₂₂−C₂₈ and (iii) benzyl alcohol esters of the very long-chain saturated fatty acids C₂₆ and C₂₈. The analysis and the structure assignments were carried out by gas chromatography coupled with mass spectrometry and by comparison with synthetic authentic model compounds. This work provided precise data on the chemical nature of the wax esters present in olive oil and should represent a means to detect adulteration of higher-grade olive oil with less expensive pomace olive oil and seed oils.     

Substrate preferences for lipase-mediated acyl-exchange reactions with butteroil are concentration-dependent

Substrate preferences for pancreatic lipase-mediated acyl-exchange reactions with butteroil were concentration-dependent for the series of acyl donors and alcohol acceptors evaluated. For acidolysis reactions, the initial reaction rates and percent reaction yields after 18 h at 50 μmol acyl donor per gram substrate mixture were similar forn-fatty acids and their methyl and glycerol esters. At 400–500 μmol g⁻¹ (and greater), order of initial reaction rates and percent reaction yield was fatty acid glycerol esters > fatty acid methyl esters > fatty acids. At concentrations above 300–500 μmol g⁻¹, reaction inhibition was observed for fatty acid substrates, and inhibition took place at lower concentrations for the shorter-chainlength fatty acids of those evaluated (5–17 carbons). Inhibition was primarily attributed to acidification of the microaqueous environment of the lipase. Desorption of water by the fatty acid substrate may be a secondary mode of inhibition. The concentration dependence of initial reaction rates and percent reaction yield was similar for then-alcohol substrates evaluated (2–15 carbons) for alcoholysis reactions with butteroil. Optimum alcohol concentration was 375–500 μmol g⁻¹ (except for butanol, which was 1 mmol g⁻¹, above which reaction inhibition was observed. Inhibition was attributed to desorption of water from the enzyme by the alcohol substrate. Relative reactivity of classes of alcohols for this reaction system was primary alcohols > secondary alcohols > tertiary alcohols. Generally, alcoholysis reactions were faster than acidolysis reactions, and triacylglycerols were the best substrates for acidolysis reactions with butteroil at high levels (up to 2 mmol g⁻¹) of acyl donor substrate.     

On the composition of Iranian olive oil

Two samples of virgin olive oil and one sample of hexane-extracted husk oil coming from Iran were examined. The analyses included physical and chemical characteristics, the composition of total fatty acids and fatty acids at the glyceride 2-position by gas liquid chromatography (GLC) of methyl esters, the triglycerides composition calculation according to Vander Wal theory, the separation of the alcoholic fractions (sterols, 4-methylsterols, triterpene alcohols, triterpene dialcohols and aliphatic alcohols) of the unsaponifiable matter by thin layer chromatography (TLC), the quantitation and the composition of these fractions by GLC of TMS derivatives. The results were in line with data from literature for olive oils of different origin, with the exception of: a high content of unsaponifiable matter (1.75 and 1.95% for virgin oils, 5.33% for husk oil); a high amount of sterols for husk oil (562 mg/100 g oil); a low content of SE 30 apparent β-sitosterol for husk oil (91.1%); a low amount of triterpene dialcohols (1 mg/100 g oil) and triterpene alcohols (78 and 91 mg/100 g oil) for virgin oils; a content of cycloartenol (60.2–66.9%) higher than the 24-methylenecycloartanol one (22.8–26.6%; a content of C₂₄ linear saturated alcohol (33.9–38.0%) slightly higher than the C₂₆ alcohol one (29.3–32.8%).     

Herstellung,Analyse und DC-Trennung von Fettsäurepartialestern mehrwertiger Alkohole

Preparation, Analysis and TLC-Separation of Partial Esters of Fatty Acids with Polybasic Alcohols Direct esterification of 99% capric acid, lauric acid, myristic acid, palmitic acid and stearic acid with ethyleneglycol, diethyleneglycol, thiodiethyleneglycol, triethyleneglycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,2,4-butanetriol, glycerol, 1,2,6-hexanetriol, trimethylolpropane and pentaerythritol in a molar ratio of 1 :1.25 yields 100 different partial esters of fatty acids. These partial esters are extensively freed from the polyhydric alcohols by washing with sodium sulfate solution and recrystallization in ethanol. Chemical constants and TLC-separation into classes and into polyhydric alcohols permit the evaluation of these compounds as emulsifiers, stabilizers and solubilization acids. All the partial esters of the fatty acids are mixtures, which can be separated by TLC according to the polyhydric alcohol moiety into monoester, diester, triester and tetraester; furthermore, the separation of positional isomers of monoesters and diesters is possible. Several observations made during the synthesis and analysis of partial esters of fatty acids are reported.     

Black currant seed oil feeding and fatty acids in liver lipid classes of guinea pigs

Guinea pigs were fed one of three diets containing 10% black currant seed oil (a source of gamma-linolenic (18∶3 n−6) and stearidonic (18∶4 n−3) acids), walnut oil or lard for 40 days. The fatty acid composition of liver triglycerides, free fatty acids, cholesteryl esters, phosphatidylinositol, phosphatidylserine, cardiolipin, phosphatidylcholine and phosphatidylethanolamine were determined. Dietary n−3 fatty acids found esterified in liver lipids had been desaturated and elongated to longer chain analogues, notably docosapentaenoic acid (22∶5 n−3) and docosahexaenoic acid (22∶6 n−3). When the diet contained low amounts of n−6 fatty acids, proportionately more of the n−3 fatty acids were transformed. Significantly more eicosapentaenoic acid (EPA) (20∶5 n−3) was incorporated into triglycerides, cholesteryl esters, phosphatidylcholine and phosphatidylethanolamine of the black currant seed oil group compared with the walnut oil group. Feeding black currant seed oil resulted in significant increases of dihomogamma-linolenic acid (20∶3 n−6) in all liver lipid classes examined, whereas the levels of arachidonic acid (20∶4 n−6) remained relatively stable. The ratio dihomo-gamma-linolenic acid/arachidonic acid was significantly (2.5-fold in PI to 17-fold in cholesteryl esters) higher in all lipid classes from the black currant seed oil fed group.     

Comparison of some commercial waxes by gas liquid chromatography

Volatile components (hydrocarbons, monoesters, free acids as methyl esters and free alcohols as acetates) of seven unhydrolyzed commercial waxes-ouricury, carnauba, Chinese insect, lac, esparto, candelilla and Japan wax—have been analyzed and compared by gas liquid chromatography. Though appreciable portions of the waxes were nonvolatile, the results were sufficient to distinguish the seven waxes completely. Methanolysis products were analyzed directly by gas liquid chromatography, and the results agreed with those previously obtained for hydrolysis products of these waxes. Ouricury wax gave 18% C₂₄−C₃₄ αω-diols and 4% C₂₄−C₃₂ ω-hydroxy acids, in addition to 28% C₂₀−C₃₂ aciods and 17% C₂₂−C₃₄ alcohols, on methanolysis. NRCC No. 13387.     

Lipase-catalyzed glycerolysis of soybean oil in supercritical carbon dioxide

The transesterification of soybean oil with glycerol, 1,2-propanediol, and methanol by an immobilized lipase in flowing supercritical carbon dioxide for the synthesis of monoglycerides is described. A lipase from Candida antarctica was used to catalyze the reaction of soybean oil with glycerol, 1,2-propanediol, ethylene glycol, and methanol. Reactions were performed in supercritical carbon dioxide at a density of 0.72 g/L and at a flow rate of 6 μL/min (expanded gas). The substrates were added at flows ranging from 2.5 to 100 μL/min. Monoglycerides were obtained at up to 87 wt%, and fatty acid methyl esters at nearly 100 wt%. The reactivity of the alcohols paralleled the solubility of the substrate in liquid carbon dioxide. Glycerol has the slowest reaction rate, only 2% of that of methanol.     

Trans-6-hexadecenoic acid and the corresponding alcohol in lipids in the sea anemoneMetridium dianthus

Trans-6-hexadecenoic acid was found in polar lipids, triglycerides, was esters and diacylglyceryl ethers of the sea anemoneMetridium dianthus from Passamaquoddy Bay. The corresponding alcomaquoddy Bay. The corresponding alcohol also apparently occurs in the wax esters of this species. The long-chain (C₂₀, C₂₂) monoethylenic alcohols reported for other species of sea anemones from neighboring waters were absent and the major alcohol and glyceryl ether chain both had 16∶0 structures. The isomers of C₁₈ and C₂₀ monoethylenic fatty acids in polar lipids and triglycerides were unusual in their high proportion of theω ₇ isomer. These two lipids also contained higher proportion of the polyunsaturated fatty acids than the others.     

Selectivity of potato tuber lipid acyl hydrolase toward long-chain unsaturated FA in esterification reactions with glycerol analogs in organic media

FA selectivity of a Celite-immobilized potato lipid acyl hydrolase (LAH) in esterification reactions with long-chain FA, including stearic acid (18∶0), oleic acid (18∶1), linoleic acid (18∶2), α-linolenic acid (18∶3), EPA (20∶5), and DHA (22∶6), and alcohol co-substrates (n-propanol, isopropanol, 1,3-propanediol, and glycerol) was studied in isooctane. Immobilized LAH was selective for FA of greater degrees of unsaturation (18∶3>18∶2>18∶1>18∶0) for all alcohol acceptors evaluated. Selectivity of LAH toward unsaturated C₁₈ FA increased with an increase in water activity (a _w ) from 0.19 to 0.90 for n-propanol, isopropanol, and 1,3-propanediol as alcohol co-substrates. In contrast, with glycerol as the alcohol cosubstrate, selectivity of LAH toward these unsaturated C₁₈ FA increased with a decrease in a _w from 0.90 to 0.19. In addition, immobilized LAH strongly discriminated against EPA and DHA for both 1,3-propanediol and glycerol as alcohol co-substrates.     

Synthesis and Characterization of New Biodiesels Derived From Oils of Plants Growing in Northern Wisconsin and Minnesota

We report on the preparation and selected properties of some new biodiesels which we synthesized from oils of plants growing in Northern Wisconsin and Minnesota. The composition and the low-temperature properties such as crystallization onset T _c and end of melting T _m investigated with the help of differential scanning calorimetry are presented. Some of these biodiesels exhibited remarkably good low-temperature characteristics. In order to further improve these properties, we use a variety of alcohols during the transesterification process, including isopropyl, 2-butyl, and isoamyl alcohols. Using several parameters such as oil content and crystallization onset temperature T _c, plant species that appear most promising have been identified, among those highbush cranberry (T _c ≈ −31 °C for its methyl esters, T _c ≈ −41 °C for its 2-butyl esters), dotted horsemint (T _c ≈ −17 °C for its methyl esters, T _c ≈ −40 °C for its 2-butyl esters), and American hazelnut (T _c ≈ −19 °C for its methyl esters, T _c  ≈ −30 °C for its 2-butyl esters).     

Conjoined crystals. I. composition and physical properties

Conjoined Crystals is the name given to a new food emulsifier whose special properties are associated with its content of glycerol monoester in a stabilized α-crystalline form (6). It consists of the mixture of crystals formed by cooling a melt containing approximately equal molecular proportion of certain long chain fatty acid monoesters of glycerol and of 1,2-propanediol. A practical composition contains a blend of glycerol monostearate and 1,2-propanediol monostearate. Conjoined Crystals disperse readily in water and retain this ability for periods of over a year, a property which appears to be closely associated with their effectiveness in baking and in other applications. This water dispersibility contrasts with the behavior of the usual modification of glycerol monostearate which is difficult to disperse in water. Infrared analysis indicated that the major part of the glycerol monoester in the mixed crystals is in the α-crystalline modification. Studies by X-ray diffraction supported this conclusion. Thus, we have consistently associated ready water dispersibility and the α-form with the enhanced emulsifying ability. Communication No. 293.     

Solubilities of fatty acids and derivatives in acetone

Summary An improved “synthetic” method of determining solubilities has been described which combines simplicity with accuracy. Saturated fatty acids with even numbers of carbons from C₆ to C₁₈ and oleic, linoleic, and linolenic acids, their methyl esters, their simple triglycerides and their corresponding alcohols have been prepared in purified form. The solubilities in acetone of their most stable forms have been determined from ordinary room temperatures down to about −70°C. or to temperatures where they are only slightly soluble. The precipitation of unstable polymorphs from solutions was observed in the case of palmityl alcohol. Hormel Institute Publication No. 159, a report of work done under contract with the U. S. Department of Agriculture and authorized by the Research and Marketing Act of 1946. The contract has been supervised by the Eastern Utilization Research Branch of the Agricultural Research Service.     

Fatty acids and fatty alcohols of wax esters in the orange roughy: Specific textures of minor polyunsaturated and branched-chain components

Open-tubular gas chromatography was carried out on fatty acids and alcohols obtained from wax esters of the orange roughy,Hoplostethus atlanticus, caught at sea off New Zealand. The major (above 5%) components were 16∶1(n−7), 18∶1(n−9) and (n−7), 20∶1(n−9) and (n−7), and 22∶1(n−11, n−13) as fatty acids, and 16∶0, 18∶0, 18∶1(n−9), 20∶1(n−9) and (n−7), and 22∶1(n−11, n−13) as fatty alcohols. The total percentages of the minor components were 10% in the acids and 26% in the alcohols. The 22∶1/20∶1 ratio of the fatty alcohols obtained in this study was less than 1.0, although the ratio for the Atlantic orange roughy has been reported as being greater than 1.0. The contents of polyenes were as low as 2.48% in the acids and 0.95% in the alcohols, but their compositions showed some specific features. The percentages of the C₁₆−C₂₂ dienes in the total polyenes were remarkably high, 57.7% of these acids and 53.1% of these alcohols. The most important dienes were 18∶2(n−6) in the acids and 20∶2(n−6) in the alcohols.     

Separation of vitamin E (tocopherol,tocotrienol, and tocomonoenol) in palm oil

Previous reports showed that vitamin E in palm oil consists of various isomers of tocopherols and tocotrienols [α-tocopherol (α−T), α-tocotrienol, γ-tocopherol, γ-tocotrienol, and δ-tocotrienol), and this is normally analyzed using silica column HPLC with fluorescence detection. In this study, an HPLC-fluorescence method using a C₃₀ silica stationary phase was developed to separate and analyze the vitamin E isomers present in palm oil. In addition, an α-tocomonoenol (α−T₁) isomer was quantified and characterized by MS and NMR. α−T₁ constitutes about 3–4% (40±5 ppm) of vitamin E in crude palm oil (CPO) and is found in the phytonutrient concentrate (350±10 ppm) from palm oil, whereas its concentration in palm fiber oil (PFO) is about 11% (430±6 ppm). The relative content of each individual vitamin E isomer before and after interesterification/transesterification of CPO to CPO methyl esters, followed by vacuum distillation of CPO methyl esters to yield the residue, remained the same except for α−T and γ−T₃. Whereas α−T constitutes about 36% of the total vitamin E in CPO, it is present at a level of 10% in the phytonutrient concentrate. On the other hand, the composition of γ−T₃ increases from 31% in CPO to 60% in the phytonutrient concentrate. Vitamin is present at 1160±43 ppm, and its concentrations in PFO and the phytonutrient concentrate are 4,040±41 and 13,780±65 ppm, respectively. The separation and quantification of α−T₁ in palm oil will lead to more in-depth knowledge of the occurrence of vitamin E in palm oil.     

Fatty alcohols

“Fatty” or higher alcohols are mostly C₁₁ to C₂₀ monohydric compounds. In probably no other homologous aliphatic series is the current balance between natural and synthetic products so vividly evident. Natural sources, such as plant or animal esters (waxes), can be made to yield straight chain (normal) alcohols with a terminal (primary) hydroxyl, along with varying degrees of unsaturation. In the past, socalled fatty alcohols were prepared commercially by three general processes from fatty acids or methyl esters, occasionally triglycerides. Fatty acids add hydrogen in the carboxyl group to form fatty alcohols when treated with hydrogen under high pressure and suitable metal catalysts. By a similar reaction, fatty alcohols are prepared by the hydrogenation of glycerides or methyl esters. Fatty alcohols are also prepared by the sodium reduction of esters of fatty acids in a lower molecular weight alcohol. The sodium reduction method was ordinarily too expensive; it was displaced early by the other methods; finally most unsaturated alcohols made by this route were largely replaced. Methyl ester reduction continues to provide perhaps 20% of the saturated fatty alcohols, and selective hydrogenation with the use of special catalysts such as copper or cadmium oxides was developed for the production of oleyl alcohol. Synthetic or petroleum technology for long chain alcohols include the Ziegler process, useful for straight chain, even-numbered saturated products. A second is the carbonylation and reduction of olefins affording medium or highly branched chain alcohols. Paraffin oxidation affords mixed primary alcohols. Fatty alcohols undergo the usual reactions of alcohols. They may be reacted with ethylene oxide to yield a series of polymeric polyoxyethylene alcohols or with acetylene under pressure to yield vinyl ethers or with vinyl acetate to give vinyl ethers.     

Potential synthetic lubricants: Esters of C18-saturated cyclic acids

A series of 16 esters of C₁₈-saturated cyclic acids (HCal) were prepared, and partial evaluation showed that several have qualities that recommend them as potential low-temp lubricants. Starting materials used were primary, straight, and branched chain alcohols C₄–C₇; perfluoro alcohols; phenol; cyclohexanol; and C₁₈-saturated cyclic alcohols prepared from cyclic acids. Viscosities were measured at −40, 100, and 210F. Their viscosity indexes ranged from 26 to 143. Pour points or melting points of the esters ranged from −27 to −96F. The oxidative stability of these esters measured at 347F according to a modification of the test method for military specification MIL-L-7808 was in nearly all cases equal or superior to the control bis-2-ethylhexyl sebacate. More severe oxidation tests showed the esters of HCal to be slower than the control in the development of acidic decomposition products. Presented at AOCS meeting, New Orleans, La., April 1964. A laboratory of the No. Utiliz. Res. and Dev. Div., ARS, USDA.