Direct ethoxylation of fatty methyl ester over Al-Mg composite oxide catalyst

For the purpose of estimating the reaction mechanism of the direct ethoxylation of a fatty ester in the presence of an Al-Mg composite oxide catalyst, a labeled fatty methyl ester C₁₁H₂₃CO¹⁸OCH₃ containing ¹⁸O isotope was synthesized and directly ethoxylated. The product was evaluated by gas chromatography-mass spectrometry (GC-MS). The GC-MS spectra showed that the ¹⁸O isotope label was present only in the methoxy group at the molecular end of the ethoxylated fatty methyl ester. This supports the reaction mechanism of coordination anionic polymerization where the bond between the acyl and methoxy groups of the fatty methyl ester molecule was broken, caused by the bifunctional effect of the acid-base active sites; an intermediate chemisorption species was formed; and then ethylene oxide was addition-polymerized sequentially, in parallel.     

Reduction of Vegetable Oil-Derived Fatty Acid Methyl Esters toward Fatty Alcohols without the Supply of Gaseous H2

An alternative route to the conventional one for fatty alcohol synthesis was investigated. It was possible to synthesize lauryl alcohol from methyl laurate via reduction by transfer of hydrogen and hydride in liquid phase, in noncatalytic reactions and without the supply of H₂ gaseous. Pure NaBH₄ or alumina-supported NaBH₄ and methanol were used as co-reactants and 100% fatty alcohol selectivities were achieved. The aim of supporting the metal hydride was to increase its stability and achieve the full recovery of the solid at the end of reaction. When alumina-supported NaBH₄ was used, a final fatty alcohol yield of 93% was achieved. The use of methanol and NaBH₄ in amounts higher than stoichiometric is important to generate alkoxyborohydride anions which act as better reducing species than NaBH₄. The reaction conditions effect was investigated and the role of short carbon chain alcohol structure was elucidated. The effect of fatty acid methyl ester structure was also studied. Fatty acid methyl esters with shorter carbon chain length and without unsaturation (methyl laurate, methyl myristate) were easily reduced using NaBH₄/Al₂O₃ and methanol reaching high conversions and fatty alcohol selectivities. Unsaturated fatty acid methyl ester with longer carbon chain (methyl oleate) introduced steric hindrance which disfavoured interaction between ester and reducing solid surface and fatty acid methyl ester conversion was noticeably lower. A reaction mechanism based on alkoxyborohydride anions as the actual reducing species was proposed. This mechanism fully interprets results obtained during fatty acid methyl ester reduction using short carbon chain alcohols and metal hydride.     

Phytanic acid α-hydroxylation by bacterial cytochrome P450

Fatty acid α-hydroxylase, a cytochrome P450 enzyme, from Sphingomonas paucimobilis, utilizes various straight-chain fatty acids as substrates. We investigated whether a recombinant fatty acid α-hydroxylase is able to metabolize phytanic acid, a methyl-branched fatty acid. When phytanic acid was incubated with the recombinant enzyme in the presence of H₂O₂, a reaction product was detected by gas chromatography, whereas a reaction product was not detected in the absence of H₂O₂. When a heat-inactivated enzyme was used, a reaction product was not detected with any concentration of H₂O₂. Analysis of the methylated product by gas chromatography-mass spectrometry revealed a fragmentation pattern of 2-hydroxyphytanic acid methyl ester. By single-ion monitoring, the mass ion and the characteristic fragmentation ions of 2-hydroxyphytanic acid methyl ester were detected at the retention time corresponding to the time of the product observed on the gas chromatogram. The K _m value for phytanic acid was approximately 50 μM, which was similar to that for myristic acid, although the calculated V _max for phytanic acid was about 15-fold lower than that for myristic acid. These results indicate that a bacterial cytochrome P450 is able to oxidize phytanic acid to form 2-hydroxyphytanic acid.     

Ethylene adduct of conjugated octadecadienoic acids: I. Peracid oxidation products

8-(4-n-Hexylcyclohex-2-enyl)octanoic acid obtained by the addition of ethylene totrans,trans-9,11-octadecadienoic acid was treated with 28% hydrogen peroxide in acetic or formic acid to give the hydroxyacetoxy or-formoxy derivative. Saponification of the hydroxyacetoxy derivative yielded two crystalline glycols. The hydroxyformoxy fatty acid was converted in one step either to the glycol ester, methyl 8-(4-n-hexyl-2,3-dihydroxycyclohexyl)octanoate, by reaction with anhydrous hydrochloric acid in methanol or to the acetone derivative of the glycol ester by treatment with dimethoxypropane and anhydrous hydrochloric acid in methanol. Epoxidation of the C₂₀ cyclohexene fatty methyl ester gave the oxirane derivative. A ring opening reaction of the diol acid with periodic acid yielded 9,12-diformylstearic acid. Presented in part at the AOCS-AACC Meeting, Washington, D.C., April 1968. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Fatty acid methyl ester as reactive diluent in thermally cured solvent-borne coil-coatings—The effect of fatty acid pattern on the curing performance and final properties

Four different fatty acid methyl esters (FAMEs): rape seed methyl ester (RME), tall oil methyl ester (TOME), and two types of linseed oil methyl ester (Linutin) have been studied as reactive diluents in thermally cured solvent-borne coil-coatings. The purpose was to evaluate the effect of fatty acid methyl ester structure on the curing performance and final properties of the coating. The permanent incorporation of the reactive diluent via transesterification reaction has been followed with ¹H NMR analysis of model systems. Dynamic mechanical analysis (DMA) measurements, of free-standing films, show that the glass transition temperature (T_g) decreases upon addition of the reactive diluent. Both the amount of incorporated reactive diluent and the final film properties are affected by the number and placement of alkene-bonds in the FAME.     

Analysis of the dark-colored impurities in sulfonated fatty acid methyl ester

A fractionally distilled C₁₄−C₁₆ fatty acid methyl ester, derived from palm oil, was sulfonated with gaseous SO₃ in a falling film reactor to form an α-sulfo fatty acid methyl ester (α-SF; unbleached and unneutralized form). The included dark-colored impurities were then separated from α-SF as a diethyl ether-insoluble matter. After purification by thin-layer chromatography, the colored species were analyzed by ion-exchange chromatography, gel-permeation chromatography, and nuclear magnetic resonance spectrometry. These data suggested that the colored species were polysulfonated compounds with conjugated double bonds. Minor components in the raw fatty acid methyl ester, found by gas chromatography/mass spectrometry, were spiked into the purified methyl palmitate and then sulfonated. The unsaturated methyl ester and hydroxy ester showed the worst color results. The methyl oleate and methyl 12-hydroxystearate were then sulfonated and analyzed. Deep black products were obtained, which showed the same properties as the colored species in α-SF. It was concluded that low levels of unsaturated fatty acid methyl esters and hydroxy esters in the fatty acid methyl ester are the main causes of the coloring.     

The base‐catalyzed,low‐temperature interesterification mechanism revisited

For the base‐catalyzed interesterification reaction carried out at low (<100 °C) temperatures, a number of mechanisms have been proposed in the literature. As these mechanisms are not in accordance with experimental observations, a novel mechanism will be proposed instead. This novel mechanism assumes that the reaction of a base (such as sodium methanolate) with the oil will eventually lead to the abstraction of an α‐hydrogen from a fatty acid moiety and that the enolate anion thus formed acts as the catalytic intermediate. This enolate can re‐abstract a proton from the hydroxyl group of a partial glyceride, whereupon the resulting alcoholate attacks the carbonyl group. This leads to a new ester and a glycerolate anion that then regenerates a new enolate anion. If the enolate anion reacts with methanol, this will lead to the formation of a fatty acid methyl ester and a glycerolate anion that again regenerates an enolate anion. Reaction with water leads to catalyst inactivation by converting the enolate anion to an unreactive fatty acid moiety (free fatty acid or soap) and a partial glyceride. Thermal inactivation of the enolate intermediate is assumed to be through the formation of catalytically inactive β‐keto esters. The accelerating role of acetone is explained by assuming this compound to act as a highly mobile hydrogen transfer agent that facilitates the reaction between the glycerolate anion and the α‐hydrogen atoms in fatty acid moieties. The above assumptions are independently supported by the observation that the addition of acetone‐d₆ to an interesterifying reaction mixture leads to the almost quantitative incorporation of deuterium into the α‐position of fatty acid moieties. Theoretical calculations on the enolate–alcohol system at PM3 level are also in agreement with the enolate mechanism.     

Addition of glyoxylic acid ethyl ester to unsaturated fatty acid derivatives

The addition of glyoxylic acid ethyl ester to unsaturated fatty acid derivatives occurs with a maximum yield of 89%. The products are the corresponding 1:1-adducts. Temperature, reaction time, stoichiometry, and the concentration of the fatty acid derivative were investigated and optimized. A maximum yield was obtained with a fourfold excess of oleic acid ethyl ester, a reaction temperature of 200 °C, a reaction time of 24 h, and an oleic acid ethyl ester concentration of 1.3 mol/l.     

Metathesis of fatty esters derived from South African sunflower oil

The metathesis of the mixture of fatty monoesters derived from sunflower oil was examined using the WCL₆-(CH₃)₄Sn catalytic system. After distillation of the reactant mixture, a total conversion of 81% and a 17% yield of diesters was achieved using a 1∶1∶30 mole ratio of catalyst:cocatalyst:ester. The rate of reaction of the ethyl linoleate was double that of the oleate.     

Beiträge zur Analytik von Estersulfonaten

Contributions to the Analysis of Sulfonated Esters Several methods for the characterization and determination of α-Sulfo fatty acid methyl esters are described. The sulfonated ester is detected by thin layer chromatography on silica gel plates with tetrahydrofuran + acetone (1+9 v/v) as solvent and with pinacryptol yellow/UV-light for the visualization. Pyrolysis-gas liquid chromatogrphy with heating a sample/P₂O₅-mixture at 400°C yields the chain length distribution of the fatty acids initially used. The amount of an α-sulfo fatty acid ester is determined by extraction with i-propanol and by two-phase titration (Epton). the saponification product of the sulfonated ester is in the i-propanol insoluble part. For a quantitative determination of the α-sulfo fatty acid methyl ester by thin layer chromatography the sample solution is directly applied to the thin layer plate. A range of defined volumes, with increasing amounts of the sample are applied to the plate by means of an applicator. The chromatograms are visually compared. Ion chromatogrphy with the mobile phase, NH₃/Acetonitrile separates the α-sulfo fatty acid esters by chain-length. Determination is achieved by standards with defined chain-length.     

Modeling of the nanocrystalline-sized mesoporous zinc oxide catalyst using an artificial neural network for efficient biodiesel production

The sulfonated mesoporous zinc oxide catalyst (SO₃H–ZnO) was hydrothermally fabricated and functionalized by sulfonation to catalyze the palm fatty acid distillate (PFAD) to esters. The effect of different reaction parameters including reaction time, reaction temperature, metal ratio, and calcination temperature was modeled by artificial neural networks (ANNs) to find out the possible relative optimum conditions of the synthesized mesoporous SO₃H–ZnO catalyst for the prediction of the nanocrystalline size. Under the optimized conditions of calcine temperature 700?°C, 18?min reaction time, 160?°C reaction temperature, and 4?mmol of Zn concentration predicted a 56.41?nm size of the mesoporous SO₃H–ZnO catalyst. The acquired model was statistically verified for its utility. The quick propagation model with four nodes in the input layer, six nodes in the hidden layer and one node in the output layer (QP-4-6-1) was chosen as the final model due to its optimum statistical characteristics. Furthermore, the most effective parameter was found to be the zinc concentration whilst the reaction time demonstrated the least influence. The optimized mesoporous SO₃H–ZnO catalyst was further utilized for esterification of PFAD, depicting a high fatty acid methyl ester yield (96.11%). It shows a valuable application for the conversion of discarded oils/fats containing high free fatty acids for the production of renewable green biodiesel.     

Biodiesel production from waste cooking palm oil using calcium oxide supported on activated carbon as catalyst in a fixed bed reactor

A reactor has been developed to produce high quality fatty acid methyl esters (FAME) from waste cooking palm oil (WCO). Continuous transesterification of free fatty acids (FFA) from acidified oil with methanol was carried out using a calcium oxide supported on activated carbon (CaO/AC) as a heterogeneous solid-base catalyst. CaO/AC was prepared according to the conventional incipient-wetness impregnation of aqueous solutions of calcium nitrate (Ca(NO₃)₂·4H₂O) precursors on an activated carbon support from palm shell in a fixed bed reactor with an external diameter of 60 mm and a height of 345 mm. Methanol/oil molar ratio, feed flow rate, catalyst bed height and reaction temperature were evaluated to obtain optimum reaction conditions. The results showed that the FFA conversion increased with increases in alcohol/oil molar ratio, catalyst bed height and temperature, whereas decreased with flow rate and initial water content in feedstock increase. The yield of FAME achieved 94% at the reaction temperature 60 °C, methanol/oil molar ratio of 25: 1 and residence time of 8 h. The physical and chemical properties of the produced methyl ester were determined and compared with the standard specifications. The characteristics of the product under the optimum condition were within the ASTM standard. High quality waste cooking palm oil methyl ester was produced by combination of heterogeneous alkali transesterification and separation processes in a fixed bed reactor. In sum, activated carbon shows potential for transesterification of FFA.     

乌桕籽油制备环氧脂肪酸异辛酯的工艺

选用具有丰富不饱和键的乌桕籽油为原料,采用了水解、酯化、环氧化等一系列反应合成了环保型增塑剂环氧脂肪酸异辛酯。并通过正交试验研究了脂肪酸异辛酯的环氧化工艺,确定了合成最佳工艺为:每百克脂肪酸异辛酯,甲酸30.37g,双氧水131.49g,反应温度65℃,反应4h后环氧值可达5.71。通过红外确定了产物的构成并考察了拉伸、热稳定性等性能,结果表明环氧脂肪酸异辛酯较邻苯二甲酸二辛酯(DOP)具有更好的热稳定性和挥发迁移性。     

The composition of beeswax alkyl esters

The alkyl esters of beeswax, after isolation from the unhydrolyzed wax by preparative layer chromatography (PLC), have been analyzed directly by high temperature GLC using 1.5% OV1 as liquid phase. In two commercial wax samples examined the ester homologues are predominantly even carbon numbered ranging from C₃₆ to C₅₄. The principal alkyl esters are C₄₀, C₄₂, C₄₄, C₄₆ and C₄₈. The GLC analysis of the ester hydrolysis products revealed that the variations in ester chain length are produced by variations in the esterified primary alcohol chain lengths. The esterified fatty acid is chiefly hexadecanoic acid. The esterified fatty acids differ in composition from the free fatty acids which are also present in the wax.     

Production of ethyl ester from crude palm oil by two-step reaction with a microwave system

The production of ethyl esters of fatty acids from a feed material of crude palm oil (CPO) with a high free fatty acid (FFA) content under microwave assistance has been investigated. Parametric studies have been carried out to investigate the optimum conditions for the esterification process (amount of ethanol, amount of catalyst, reaction time, and microwave power). As a result, a molar ratio of FFA to ethanol of 1:24 with 4% wt./wt. of H₂SO₄/FFA, a microwave power of 70 W, and a reaction time of 60 min have been identified as optimum reaction parameters for the esterification process aided by microwave heating. At the end of the esterification process, the amount of FFA had been reduced from 7.5 wt.% to less than 2 wt.%. Similar results were obtained following conventional heating at 70 °C, but only after a reaction time of 240 min. Transesterification of the esterified palm oil has been accomplished with a molar ratio of CPO to ethanol of 1:4, 1.5 wt.% KOH as a catalyst, a microwave power of 70 W, and a reaction time of 5 min. This two-step esterification and transesterification process provided a yield of 80 wt.% with an ester content of 97.4 wt.%. The final ethyl ester product met with the specifications stipulated by ASTM D6751-02.     

A rapid and quantitative procedure for the preparation of methyl esters of butteroil and other fats

A simple and convenient method for the quantitative preparation of methyl esters of fatty acids from glyceride fats and oils is described. The procedure, using potassium methylate as catalyst and a heating interval of 2 min at 65C in a closed vial, is applicable to fats containing both low and high molecular weight fatty acids such as butteroil. The methyl esters of samples ranging from a few mg to 30 mg are isolated by CS₂ extraction and a TLC technique. A similar procedure using sulfuric acid in methanol as catalyst is described for the conversion of free fatty acids to methyl esters. For the routine analysis by GLC of fats and oils such as lard, tallow, soybean, cottonseed oil or butteroil, no isolation of the methyl ester is required. A CS₂ extraction carried out in the reaction vial allows the GLC analysis immediately after the reaction period (2 min). Presented at the AOCS Meeting, Philadelphia, October 1966. E. Utiliz. Ees. Dev. Div., ABS, USDA.     

Producing Fatty Acid Methyl Esters from Free Fatty Acids with Ionic Liquids as Catalyst

Three Brønsted acidic imidazole dicationic ionic liquids (ILs) with different length of alkyl chains, [C_n(Mim)₂][HSO₄]₂ (n = 3, 6, 12), were prepared and used as catalyst for the esterification reaction of free fatty acids and methanol. Taking oleic acid as model acid, the catalytic performances of the synthesized ILs for the esterification were evaluated. The main physicochemical properties of the ILs, thermal stability, acidity, solubility in common solvents, and causticity on Austenitic stainless steel 316, were examined. [C₃(Mim)₂][HSO₄]₂ demonstrated the highest catalytic activity and enabled to assess the preliminary optimum esterification condition of oleic acid and methanol. Under optimized reaction conditions, the yield of oleic acid methyl ester was up to 95 %. The ILs have great potential as catalysts for producing fatty acid methyl esters from long‐chain free fatty acids.     

Soy lecithin-monoester interchange reaction by microbial lipase

Modification of the fatty acid composition of soy lecithin, principally at its 1-position, was investigated by interchange reaction with the methyl ester of individual fatty acids and a lipase as the catalyst. The consequent effect on the surface activity of soy lecithin was also examined. The interchange reaction was carried out by heating a mixture of soy lecithin and methyl ester of a fatty acid at 60°C for 48 h with 10% (by weight of the reactants) Mucor miehei lipase. The lipase was filtered from the reaction mixture, and the product was isolated by combination of acetone extraction, which removed the methyl ester fraction, and by preparative thin-layer chromatography separation. The soy lecithin showed distinct change in its fatty acid composition in the sn-1 position. Capric acid was incorporated by 8.4%, while lauric acid and myristic acid were introduced at 14.1 and 15.7%, respectively. The linolenic acid percentage was increased by about 10 units. The interfacial tension of soy lecithin changed significantly after incorporation of various saturated fatty acids.     

C18‐unsaturated branched‐chain fatty acid isomers: Characterization and physical properties

Iso‐oleic acid is a mixture of C₁₈‐unsaturated branched‐chain fatty acid isomers with a methyl group on various positions of the alkyl chain, which is the product of the skeletal isomerization reaction of oleic acid and is the intermediate used to make isostearic acid (C₁₈‐saturated branched‐chain fatty acid isomers). Methyl iso‐oleate, a mixture of C₁₈‐unsaturated branched‐chain fatty acid methyl ester isomers, is obtained via acid catalyzed esterification of iso‐oleic acid with methanol. The branched‐chain materials are liquid at room temperature and their “oiliness” property makes them an attractive candidate for the lubricant industry. In this paper, we report characterization of these branched‐chain materials using comprehensive two‐dimensional GC with time‐of‐flight mass spectrometry (GC × GC/TOF‐MS) and their physical and lubricity properties using tribology measurements.     

Convenient preparation of fatty ester cyclic carbonates

The cyclic carbonate moiety finds many industrial applications because of its unique chemistry and properties. Phosgene, a highly toxic and corrosive reagent, has been utilized in the past to prepare low yields of fatty ester compounds ( 1 ) that contain a five‐membered cyclic carbonate group. Herein, we show (CH₃)₄N^+?HCO₃, tetramethylammonium hydrogen carbonate (TMAHC), to react efficiently with methyl or 2‐ethylhexyl 9(10)chloro‐10(9)‐hydroxyoctadecanoate at 50–55 °C to give methyl or 2‐ethylhexyl 8‐(2‐oxo‐5‐octyl‐1,3‐dioxolan‐4‐yl)octanoate, 1a and 1b , respectively. These fatty acid ester carbonates were isolated in good yields ranging from 84% to 91% after purification by vacuum distillation. The purified fatty ester carbonate compounds were characterized by ¹H and ¹³C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gas chromatography‐mass spectrometry using electron impact ionization and positive chemical ionization techniques. This work demonstrates that the five‐membered cyclic carbonate ring can be effectively introduced onto the alkyl chains of fatty acid esters using fatty ester chlorohydrins and (CH₃)₄N^+?HCO₃ chemistry. The well‐known lubricating and polymeric properties of the carbonate moiety make these interesting cyclic oleochemical carbonates potential candidates for industrial lubricant, plasticizer, or polymer applications.