Hydrogen peroxide variables in increasing epoxidation efficiency

Summary Variations in quantity and concentration of hydrogen peroxide were studied in epoxidation of soybean oil by using the partially preformed peracetic acid epoxidation method. Use of a hydrogen peroxide/olefin mole ratio as low as 1.05/1 yields epoxidized soybean oil that meets the low iodine number and high epoxide content characteristics required for stabilizer-plasticizer use. Use of a hydrogen peroxide/olefin mole ratio as low as 0.50/1 results in more than 95% hydrogen peroxide utilization and yields epoxidized soybean oil containing more than two epoxide groups per molecule. Products of this type may be of interest for recently proposed applications in alkyd, polyester, and epoxy resins. Increasing the hydrogen peroxide concentration to 70% in epoxidation permits reduction of acetic acid usage to half that required when 50% hydrogen peroxide is used. Agitation control is also necessary for optimum results. A two-step epoxidation method can be used to avoid formation of potentially detonable mixtures in epoxidation with 70% hydrogen peroxide by the partially preformed peracetic acid method. Presented at the 32nd annual meeting, American Oil Chemists' Society, Chicago, Ill., October 20–22, 1958.     

无味环氧豆油的合成技术研究

本文阐述无味环氧豆油的合成技术，将精制大豆油，乙酸与其它辅料按配方比例投入反应釜，再慢慢滴加双氧水，使之环氧化反应，待反应完全后，经水洗，中和，脱水等一系列工艺，制成无味环氧豆油成品。这种合成方法，工艺简单，产品质量稳定优良。     

The chemistry of metathesized soybean oil

New materials derived from metathesized soybean oil have been prepared and characterized. Thermal polymerization of metathesized soybean oil in the presence of air results in yellow, brittle gels. These materials display a curious tendency to produce audible popping sounds when exposed to chlorinated organic solvents, such as chloroform or dichloromethane. Complete hydrogenation of metathesized soybean oil has been accomplished in excellent yields utilizing 10% palladium on carbon in dichloromethane. A new, very mild, effective epoxidation procedure for soybean oil, utilizing methyltrioxorhenium (VII) (MTO) and pyridine as the catalyst system and hydrogen peroxide as the oxidant, has been developed. This epoxidation reaction affords excellent yields of epoxidized soybean oil with some control of the degree of epoxidation at very low MTO concentrations (< 0.5 mol%). This reaction is also very effective for the epoxidation of metathesized soybean oil to higher molecular weight epoxidized soybean oil materials.     

Chemical epoxidation of a natural unsaturated epoxy seed oil fromVernonia galamensis and a look at epoxy oil markets

Since 1963, production of all epoxy esters has ranged from 60 to 150 million lb annually, a steady 7% of the 1 to 2 billion lb of annual plasticizer production. Growth rates in production averaged 4.3% for all plasticizers, 3.8% for all epoxy esters and 5.0% for epoxidized soybean oil (ESBO). ESBO accounted for 70–76% of total epoxy ester production (1963–1982). The natural liquid epoxy oil fromVernonia galamensis seed, with oxirane value (4.1%) and viscosity (100 cps) similar to some commercial epoxy fatty esters but with molecular weight similar to epoxidized vegetable oils, combines some of the properties of both commercial types. Chemical epoxidation ofVernonia oil raises the oxirane content to 8.2, intermediate between ESBO and epoxidized linseed oil (ELSO), while consuming less of the costly epoxidizing reagents. Epoxidation proceeds in stepwise fashion through partially epoxidized products, which are converted to final product. Since the major fatty components ofVernonia oil arecis-12,13-epoxy-9-octadecenoic (75%) and linoleic (13%) acids, further epoxidation produces fatty acids that are specifically epoxidized at the 9,10- and 12,13-positions, and the major product has 6 epoxy units per triglyceride molecule. The resulting mixture of products has compositional and physical properties distinctly different from commercial samples of ESBO and ELSO.     

Modification of soybean oil for intermediates by epoxidation,alcoholysis and amidation

Vegetable oils are a major source of many base chemicals. Unfortunately, most vegetable oils exhibit lower thermal and oxidation stability because of double bonds and even worse low-temperature behaviors. These physical and chemical properties can be improved by various chemical modifications. The catalytic hydrogenation of soybean oil (SBO) over 25% Ni/SiO₂ and 5% Pt/C is one of them, and the epoxidation of soybean oil and reduced soybean oil (RSBO) was carried out by using 30% of hydrogen peroxide and acetic acid in the presence of conc. sulfuric acid, and/or acidic Amberlyst 15 resin catalyst. Various alcohols and amines were added to the epoxidized soybean oil (ESBO) in the hope of improving lubricant properties. The reaction products were carefully analyzed by means of ¹H-NMR, FT-IR spectroscopies and GC-MS spectrometry. This paper covers the epoxidation of virgin and RSBOs, alcoholysis and amidation of ESBO and SBO. Finally, the structures of cross linked products synthesized from ESBO and SBO with 1,6-hexamethylendiamine were proposed.     

绿色增塑剂环氧大豆油的合成与表征

用自制的催化剂合成了一种环氧大豆油。通过L16(45)正交试验考察了双氧水用量、催化剂用量、反应时间和反应温度对环氧大豆油环氧值的影响。结果表明:在双氧水用量100份、催化剂用量0.5份(大豆油用量定为100份)、反应温度50℃、反应时间12.5 h的最佳工艺条件下,产品的环氧值为6.58%,碘值为0.83 gI/100g。产品通过红外和核磁共振表征,确定大豆油被环氧化生成环氧大豆油。     

Effects of Vegetable Oil Composition on Epoxidation Kinetics and Physical Properties

In this article, we investigate the role of triacylglycerol composition on the properties of epoxidized vegetable oils and the kinetics of the epoxidation process under conditions comparable to commercial epoxidation. Commodity soybean oil (24% oleic acid, 50% linoleic acid, and 7% linolenic acid), high‐oleic soybean oil (75% oleic acid, 8% linoleic acid, and 2.5% linolenic acid), and linseed oil (11% oleic acid, 15% linoleic acid, and 64% linolenic acid) were each epoxidized to various extents. Epoxidation rate, viscosity, differential calorimetry, and X‐ray diffraction data are presented for these oils and interpreted in the context of their fatty acid profile (mostly oleic, linoleic, or linolenic). While fully epoxidized soybean oil is widely commercially available and used in an increasing array of industrial applications, information relating to partially epoxidized oils and epoxidized oils of other cultivars is less well known.     

环氧大豆油新工艺的研究

研究了采用无溶剂合成环氧大豆油的新工艺。以大豆油、冰醋酸与双氧水为原料经催化、碱洗、水洗、减压蒸馏后制得环氧值≥6.0%的高质量产品，同时通过L9(3^4)正交试验对反应的工艺条件，原料配比与影响产品质量的各种因素进行了研究，确定最佳工艺条件是大豆油：双氧水：冰醋：浓硫酸之比是1：0.33：0.23：0.02。     

均匀设计优化环氧橡胶籽油的制备工艺

以橡胶籽油、甲酸和双氧水为原料,磷酸作催化剂,采用无溶剂法合成环氧橡胶籽油,采用均匀设计法研究了甲酸用量、反应时间及双氧水用量等对环氧值的影响。结果表明,最佳制备工艺条件为:橡胶籽油100 g,甲酸12.80 g,质量分数为30%的双氧水50.53 g,反应时间6 h,反应温度50～55℃,产品环氧值达11.68%。     

环氧大豆油增塑剂的合成

本合成采用无溶剂一步法环氧化工艺，取消了苯作溶剂，用新型催化剂代替硫酸，在稳定剂上用３０％双氧水合成的环氧大豆油，环氧值达９５％以上。     

Revisiting the Enzymatic Epoxidation of Vegetable Oils by Perfatty Acid: Perbutyric Acid Effect on the Oil with Low Acid Value

Enzymatic epoxidation of vegetable oils in the presence of free fatty acids has been well studied in recent years, by mainly using long chain fatty acids (e.g., stearic acid) as the active oxygen carrier. However, for the previous enzymatic processes, the acid value (AV) of final epoxidized oils using long chain fatty acids is high, and the free fatty acid is not easily removed in the post treatment with water. Aiming at developing a more sustainable process, enzymatic epoxidation of sunflower oil was revisited using different free fatty acids catalyzed by Novozym 435 (lipase B from Candida antarctica, provided by Novozymes, Bagsvaerd, Denmark). When long chain stearic acid was introduced into the epoxidation in toluene solvent, the epoxy oxygen group content (EOC) of 6.41 ± 0.19 % was obtained. Due to the poor water solubility of stearic acid, the AV of the final epoxidized oil product was very high (53.40 ± 1.34) after it was washed with water. Alternatively, current study shows that the epoxidation process using short chain butyric acid produced the final epoxidized oil with lower AV of 2.57 ± 0.11. When the enzymatic epoxidation of sunflower oil was optimized in the presence of butyric acid and Novozym 435, EOC of 6.84 ± 0.21 % was obtained, reaching an oxriane conversion of 96.4 ± 3.0 %. Therefore, introducing short chain butyric acid as an active oxygen carrier will provide an alternative to the present enzymatic epoxidation process and produce the desired epoxidized oil products with much lower AV only after simple water‐treatments, which will make the enzymatic epoxidation more attractive.     

Kinetics of tungsten‐catalyzed sunflower oil epoxidation studied by 1H NMR

Sunflower oil (SO) is a renewable resource that can be epoxidized, and the epoxidized SO has potential uses as an environmentally friendly and reactive material in polymeric formulations, especially for polyvinyl chloride. SO was epoxidized with peracetic acid, which was either preformed or prepared in situ. In order to optimize the formation of oxirane rings, the epoxidation and the extent of the side reactions were studied at different temperatures. The peracetic acid was obtained by acidic catalysis in the presence of a cation‐exchange resin. The optimum conversions were obtained within a 4‐h reaction period at 55 °C by the in situ epoxidation technique. The epoxidation was also carried out with hydrogen peroxide in the presence of peroxotungstic acid complexed with lipophilic phosphorus‐based ligands. ¹H NMR was used to define the new indices Δ and Ω, which are the mean numbers of C=C double bonds and oxirane rings per fatty acid chain, respectively. This allowed monitoring of the reaction and quantification of the results. Peroxotungstic catalysts appeared less performing than peracids in the epoxidation of SO, but were found very efficient for the epoxidation of the SO methyl esters.     

高品质环氧大豆油的研制

文章采用732#强酸性阳离子交换树脂为催化剂,改进型无溶剂法合成高品质环氧大豆油。实验确定了高品质环氧大豆油的最佳合成条件:采用逐步加料,按m(大豆油):m(88%甲酸):m(30%双氧水):m(催化剂)=1:0.35:1.2:0.15的比例加料,加0.5 mL 1%的EDTA稳定剂,制得的环氧大豆油品质较高。     

Improving the oxidative stability of polyunsaturated vegetable oils by blending with high-oleic sunflower oil

Mixing different proportions of high-oleic sunflower oil (HOSO) with polyunsaturated vegetable oils provides a simple method to prepare more stable edible oils with a wide range of desired fatty acid composition. Oxidative stability of soybean, canola and corn oils, blended with different proportions of HOSO to lower the respective levels of linolenate and linoleate, was evaluated at 60°C. Oxidation was determined by two methods: peroxide value and volatiles (hexanal and propanal) by static headspace capillary gas chromatography. Determination of hexanal and propanal in mixtures of vegetable oils provided a sensitive index of linoleate and linolenate oxidation, respectively. Our evaluations demonstrated that all-cis oil compositions of improved oxidative stability can be formulated by blening soybean, canola and corn oils with different proportions of HOSO. On the basis of peroxide values, a partially hydrogenated soybean oil containing 4.5% linolenate was more stable than the mixture of soybean oil and HOSO containing 4.5% linolenate. However, on the basis of volatile analysis, mixtures of soybean and HOSO containing 2.0 and 4.5% linolenate were equivalent or better in oxidative stability than the hydrogenated soybean oil. Mixtures of canola oil and HOSO containing 1 and 2% linolenate had the same or better oxidative stability than did the hydrogenated canola oil containing 1% linolenate. These studies suggest that we can obviate catalytic hydrogenation of linolenate-containing vegetable oils by blending with HOSO. Presented at the AOCS/JOCS joint meeting, Anaheim, CA, April 25–29, 1993.     

二乙醇胺开环环氧大豆油制备大豆多元醇及其性能表征

以大豆油、冰乙酸和过氧化氢为原料,硫酸为催化剂,合成了不同环氧值的环氧大豆油。再由合成的环氧大豆油与二乙醇胺在四氟硼酸作催化剂的条件下．通过开环加成反应制备了羟基值分别为261mgKOH／g、285mgKOH／g、312mgKOH／g、340mgKOH／g的4种大豆多元醇。用滴定法测定多元醇羟值,用傅立叶变换红外光谱、差示扫描量热法、热重分析法对多元醇进行了分析和表征。结果表明4种多元醇的熔点和热稳定性都随多元醇羟值增大而增大。     

Liquid–Liquid Equilibrium for Systems Containing Epoxidized Oils,Formic Acid,and Water: Experimental and Modeling

Epoxidized oils are eco-friendly plasticizers, which are industrially produced through the epoxidation reaction in a formic acid-hydrogen peroxide autocatalyzed system. The fundamental knowledge to describe the phase equilibrium of systems after epoxidation reaction is lacking, which is crucial for the design of the purification facilities. This work reported experimental data for the liquid–liquid equilibrium of three systems, i.e., epoxidized fatty acid methyl esters + formic acid + water, epoxidized fatty acid 2-ethylhexyl esters + formic acid + water, and epoxidized soybean oil + formic acid + water, in the temperature range (303.15–348.15) K under atmospheric pressure. The results indicated that the liquid–liquid equilibrium constant of formic acid in the systems followed the order of epoxidized fatty acid 2-ethylhexyl esters > epoxidized fatty acid methyl esters > epoxidized soybean oil. Moreover, the obtained experimental data were correlated using nonrandom two liquid (NRTL) and universal quasi chemical (UNIQUAC) models. The maximum root mean square deviation (RMSD) values as low as 0.0052 and 0.0263 were estimated using the NRTL and UNIQUAC model, respectively. The NRTL model is more suitable than the UNIQUAC model to describe the liquid–liquid equilibrium behavior of these ternary systems.     

Synthesis and Physicochemical Properties of Partially and Fully Epoxidized Methyl Linoleate Derived from Jatropha curcas Oil

Partial epoxidation of methyl linoleate was carried out at room temperature (30 °C) using a methyltrioxorhenium catalyst in the presence of pyridine and urea‐hydrogen peroxide. Full epoxidation of methyl linoleate was carried out using the Prilezhaev method. The reactions were monitored using the oxirane oxygen content value. The products from partial and full epoxidation were analyzed using GC‐FID, FTIR, NMR and GC–MS. Methyl 9,10‐epoxy‐12Z‐octadecenoate and methyl 12,13‐epoxy‐9Z‐octadecenoate were obtained as the major products from partial epoxidation, with a percent yield of 46 %. The product from full epoxidation afforded 97 % yield with methyl 9,10‐12,13‐diepoxyoctadecanoate as the major component. Physicochemical properties such as kinematic viscosity, viscosity index, crystallization temperature and oxidative stability were examined. Fully epoxidized methyl linoleate exhibits superior kinematic viscosity and oxidative stability due to the complete conversion of double bonds to epoxy groups. Partially epoxidized methyl linoleate exhibits intermediate kinematic viscosity, viscosity index, crystallization temperature and oxidative stability.     

The Influence of Reaction Parameters on the Epoxidation of Rapeseed Oil with Peracetic Acid

The influence of reaction parameters on the epoxidation of rapeseed oil (RO) with peracetic acid obtained in situ from the reaction between 30 wt% hydrogen peroxide and glacial acetic acid (AA) has been studied. The course of the reaction was measured by changes of the iodine number (IN) and epoxy number (EN), used to estimate the degree of rapeseed oil conversion, yield, and the selectivity of transformation to epoxidized rapeseed oil in relation to the total amount of oil undergoing the transformation. The optimal conditions of epoxidation are as follows: temperature 60 °C, molar ratio of hydrogen peroxide to rapeseed oil 9.5:1 mol/mol, molar ratio of acetic acid to rapeseed oil 1.12:1 mol/mol, stirring speed 500 rpm, and reaction time of 4 h. Under these conditions the epoxy number is equal to 0.157 mol/100 g RO and iodine number reaches low values of 0.123 mol/100 g RO. The selectivity of transformation to epoxidized RO calculated from EN and IN is 82.2%, conversion of hydrogen peroxide is 100%, conversion of RO calculated from IN is 60.8%, and yield of RO calculated from EN is 50%.     

Optimization of the chemoenzymatic epoxidation of soybean oil

The lipase Candida antarctica (Novozyme 435) immobilized on acrylic resin was used as an unconventional catalyst for in situ epoxidation of soybean oil. The reactions were carried out in toluene. The peracid used for converting TG double bonds to oxirane groups was formed by reaction of FFA and hydrogen peroxide. The reaction conditions were optimized by varying the lipase concentration, solvent concentration, molar ratio of hydrogen peroxide to double bond, oleic acid concentration, and reaction temperature. The kinetic study showed that 100% conversion of double bonds to epoxides can be obtained after 4 h. The addition of free acids was not required for the reaction to proceed to conversions exceeding 80%, presumably owing to generation of FFA by hydrolysis of soybean oil. The enzyme catalyst was found to deteriorate after repeated runs.