Epoxidation Of Vegetable Oils Research Articles

Novel Reactor for Exothermic Heterogeneous Reaction Systems: Intensification of Mass and Heat Transfer and Application to Vegetable Oil Epoxidation

A novel reactor for exothermic heterogeneous reaction systems was developed and used in a vegetable oil epoxidation process. When hydrodynamic cavitation is coupled with a static mixer, both mass and heat transfer in the reactor can be intensified effectively. The Sauter mean diameter of water/oil dispersion was 8.90 μm under hydrodynamic cavitation conditions with a relatively low inlet pressure (2.5 bar) as compared to 60.33 μm for conventional stirring approach at 500 rpm. The epoxidation temperature variation was controlled within ±1 °C even when the H2O2 was added at once, whereas the temperature rise was up to 19 °C in a stirred-tank reactor. The use of this reactor results in decreased reaction time and a simpler and safer process, with final products having quality similar to that obtained in a traditional process.

OXIDATIVE EPOXIDATION OF OLEOX AND VEGETABLE OILS

We have studied the oxidative epoxidation product of ethoxylated oleic acid (oleox) and tonnage vegetable oils: sunflower, corn, rapeseed and flax. The oxidation was carried out using hydrogen peroxide, peracetic acid and performic, which were obtained in situ using the appropriate acids and concentrated aqueous solution of hydrogen peroxide. The kinetics of oxidation was evaluated on the accumulation of the peroxide compounds, the iodine value and the number of refractive index. The final oxidation products were examined for the content of epoxy and aldehyde groups. It was shown that at the epoxidation of oleox with superoxide acids the intermediates of formic acid formed and loss faster than similar products of acetic acid. It is reflected on the character of changes in the values of iodine and peroxide value at the initial step of the process. As a result of the decomposition of the hydroperoxide derivatives the oleox aldehydes and epoxides are formed. The total content of oxidation products is changed from 3.71 to 3.84 %. It was experimentally shown that the oleox oxidation at temperatures of 55 and 65 °C did not substantially affect the dynamics of change in the number of iodine. The content of aldehyde groups in the oxidation products obtained at these temperatures is reduced. It was concluded that the oleox oxidation necessary to carry out at temperatures above 45-50 °C. It allows to obtaine the maximum content of reactive groups in the modified product. At vegetable oils oxidation study, it was found that the linseed oil has the highest oxidation rate, which contains the greatest amount of linolenic acid (46%), that probably initiates the oxidation processes. The degree of epoxidation of vegetable oils is much lower than that of oleox, probably due to a high degree of oxidation of unsaturated bonds in oils containing large amounts of polyunsaturated acids, which are the "catalysts" of the oxidation process. Relatively high levels of aldehyde and epoxy groups in sunflower oil oxidation products allows us to speak about the prospects of getting on its base materials for tanning fat.Forcitation:Chursin V.I. Oxidative epoxidation of oleox and vegetable oils. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 83-89.

Thermal Safety Assessment through the Concept of Structure–Reactivity: Application to Vegetable Oil Valorization

The concept of linear free-energy relationships, and more particularly the Taft equation, was extended to a multiphase system with several reactions and reaction centers: the epoxidation of vegetable oils and free fatty acids. The epoxidation of vegetable oils and free fatty acids by different percarboxylic acids produced in situ is an exothermic reaction system which can lead to a thermal runaway. The safety criterion time-to-maximum-rate under adiabatic conditions (TMRad), linked to the kinetics of the system, was determined with the advanced reactive system screening tool (ARSST). We have demonstrated that TMRad values for the epoxidation of vegetable oils and free fatty acids by using different carboxylic acids follow the Taft equation. The epoxidation reaction series by different carboxylic acids was found to be more sensitive to the polar effect than steric effect. It was demonstrated that, by knowing the carboxylic acid used for the epoxidation, it is possible to predict the values of TMRad.

The use of ATR‐FTIR spectroscopy to measure changes in the oxirane content and iodine value of vegetable oils during epoxidation

A rapid attenuated total reflectance Fourier transform infrared (ATR‐FTIR) method was developed to simultaneously measure for vegetable oils both their oxirane oxygen content (OOC) and the change in their iodine values (IV) that occur during their epoxidation. The method uses the peak area of the epoxy functional group absorption (1497.3–1432.0 cm−1) to measure OOC and the HCabsorption associated with a carbon–carbon double bond (3017.5–3004.2 cm−1) to determine the relative changes in iodine value (ΔIV). Calibrations were developed by gravimetrically blending epoxidized canola oil (ECO) with unreacted canola oil (CO) to vary both OOC and IV. Oils including canola, camelina, and flaxseed were epoxidized, during which the OOC and ΔIV were tracked as a function of time using both the new ATR‐FTIR procedures and the standard ASTM methods. Both the OOC and ΔIV values measured by the ATR‐FTIR method correlate well to values from standard methods (R2 ≥ 0.992 and mean relative error of <3%). The FTIR procedure is simple and fast to perform and facilitates the determination of selectivity (conversion of double bonds into oxirane group) and the end‐point for the epoxidation reaction, which requires measurement of both OOC and IV.Practical applications: The ATR‐FTIR method described provides a simple, rapid, and accurate means for the measurement of OOC as well as changes in iodine value during the epoxidation of vegetable oils. This allows for the determination of the degree of conversion of lipid unsaturation into epoxides. This method can be employed by manufacturers and research laboratories to study, control, and optimize epoxidation processes.The ATR‐FTIR methods described in this paper provide a simple and rapid means of monitoring OOC and IV changes during the epoxidation of vegetable oils. These methods are calibrated against standard titrimetric procedures and have been shown to produce similar results. It is especially useful that OOC and ΔIV, the two measures that are most relevant for monitoring the progress of a triacylglycerol oil epoxidation reaction, can be obtained from a single analysis. This facilitates monitoring and optimizing epoxidation processes. If the initial IV of oil is known, the method can also be used to calculate the yield, conversion, and selectivity of the reaction, as well as a study the reaction kinetics.

Kinetics of soybean oil epoxidation with peracetic acid formed in situ in the presence of an ion exchange resin: Pseudo-homogeneous model

A kinetic model was proposed for the epoxidation of vegetable oils with peracetic acid formed in situ from acetic acid and hydrogen peroxide in the presence of an acidic ion exchange resin as a catalyst. The model is pseudo-homogeneous with respect to the catalyst. Besides the main reactions of peracetic acid and epoxy ring formation, the model takes into account the side reaction of epoxy ring opening with acetic acid. The partitioning of acetic acid and peracetic acid between the aqueous and organic phases and the change in the phases? volumes during the process were considered. The temperature dependency of the apparent reaction rate coefficients is described by a reparameterized Arrhenius equation. The constants in the proposed model were estimated by fitting the experimental data obtained for the epoxidations of soybean oil conducted under defined reaction conditions. The highest epoxy yield of 87.73% was obtained at 338 K when the mole ratio of oil unsaturation:acetic acid:hydrogen peroxide was 1:0.5:1.35 and when the amount of the catalyst Amberlite IR-120H was 4.04 wt.% of oil. Compared to the other reported pseudo-homogeneous models, the model proposed in this study better correlates the change of double bond and epoxy group contents during the epoxidation process.

Recent advances in the field of selective epoxidation of vegetable oils and their derivatives: a review and perspective

The present critical review reports the recent progress of the last 15 years in the selective epoxidation of vegetable oils and their derivatives, in particular unsaturated fatty acids (UFAs) and fatty acid methyl esters (FAMEs).

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

AbstractEnzymatic 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.

Production of Catalyst to Vegetable Oil Epoxidation from Toxic Biomass Residue

This paper describes the preparation of a biobased catalyst derived from residual Jatropha curcas cake using a combination of low-temperature conversion and chemical treatment to be applied for epoxidation of vegetable oil. The catalyst was characterized and its performance for epoxidation of cottonseed oil was evaluated and compared with the cationic resin VPOC 1800. After 60 min of epoxidation reaction, the results showed that VPOC resin catalyst presented yields (conversion of double bonds to oxirane rings) of about 34 % and biochar catalyst had yield of 14 %. Both catalysts presented high selectivity to bis-allylic hydrogen attack and elimination of 95 % of conjugated double bonds. The biochar catalyst presented higher activity than VPOC 1800 resin catalyst. On the other hand, the VPOC 1800 has better reusability.

Highly Efficient Silica-Supported Peroxycarboxylic Acid for the Epoxidation of Unsaturated Fatty Acid Methyl Esters and Vegetable Oils

A silica-supported peroxycarboxylic acid oxidant, 2-percarboxyethyl silica (SiO2@(CH2)2COOOH), was successfully prepared and used for the epoxidation of fatty acid methyl esters (FAMEs) and vegetable oils. Among the oxidants prepared under different conditions, C-SiO2@(CH2)2COOOH (TEOS:CTES = 2:1) had the highest surface area, pore volume, and peroxide value. It also exhibited the highest activity for the epoxidation reactions. For methyl linoleate, 92.76% yield of epoxidized product was obtained at room temperature. Other unsaturated FAMEs with 1 and 3 double bonds were also efficiently converted to their epoxides. Moreover, the oxidant was also successfully applied to the epoxidation of vegetable oils, olive oil, and linseed oil with high product yield at room temperature. Finally, the used oxidant was regenerated through a simple oxidation process with H2O2 and recycled at least 5 times without much drop in the reactivity.

Facing the Hazard of Biphasic, Unstable, Highly Exothermic Process: the Case of Epoxidation of Vegetable Oils

Facing the Hazard of Biphasic, Unstable, Highly Exothermic Process: the Case of Epoxidation of Vegetable Oils

Epoxidation of oleic acid under conventional heating and microwave radiation

Epoxidized vegetable oils are used as chemical intermediates and biolubricants. Epoxidation of oleic acid as model compound for vegetable oils was performed in a batch-loop reactor. The system comprised a loop where the mixture was pumped through a cavity in which microwaves were irradiated. The reaction was executed by peroxyacetic acid formed in situ from acetic acid and hydrogen peroxide.An extensive kinetic study of oleic acid epoxidation in the batch-loop reactor was conducted by varying the reaction temperature (40–60°C), the stirring and pumping speeds as well as the molar ratios of the components. Both conventional heating and microwave irradiation were used in the experiments. Epoxidation of the double bonds in oleic acid proceeded as the main reaction, while acid-catalyzed ring opening of the epoxide appeared as the side reaction.The results obtained showed that temperature, acetic acid amount and hydrogen peroxide amount accelerated both rate of epoxidation and ring opening processes. A clear enhancement of the epoxidation kinetics was accomplished with microwave heating in comparison to conventional heating, which was attributed to selective heating by the microwaves that enabled a higher interfacial mass transfer. Microwave application to epoxidation of vegetable oils is a promising process that successfully meets all the green chemistry requirements: energy saving and eco-friendly process and products.

Thermal risk assessment of vegetable oil epoxidation

This article describes thermal risk assessment of vegetable oil epoxidation by peroxycarboxylic acid. It is a liquid–liquid system where several exothermic reactions occur. Acetic acid was used as the carboxylic acid, and oleic acid was chosen as a model molecule because it is a common fatty acid in the triglyceride molecule. Differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC) were used to determine safety criteria such as the final temperature (T Final), T D24, and time to maximum rate under adiabatic condition (TMRad). We found that the calculation of TMRad based on DSC data could be incorrect when assuming a zero-order kinetic reaction. By using a process temperature of 70 °C, the extrapolated final temperature was found to be 544 °C from DSC experiments, T D24 was estimated to 20 °C based on ARC experiment, and TMRad was calculated to 164 min from ARC experiments. These criteria indicate the process can lead to a thermal runaway. Therefore, we recommend that vegetable oil epoxidation by peroxycarboxylic acid should not be performed in batch reactor, but in semi-batch mode.

Peroxopolyoxotungsten-based Ionic Hybrid as a Highly Efficient Recyclable Catalyst for Epoxidation of Vegetable oil with H2O2

utilizationefficiency, high catalytic activity, convenient recovery and good reuse ability.Key Words : Peroxopolyoxometalate, Dicationic imidazolium ionic liquid, Epoxidation, Vegetable oil, Hy-drogen peroxideIntroductionDue to the increasing environmental concerns and petro-leum supply severity, the use of biomass as raw material forpolymers, chemicals, fine chemicals and fuel applicationshas become an imperative issue in recent years. In thiscontext, Epoxidized vegetable oils, as one kind of vegetableoils derivatives, play an important role in industry of finechemicals, which can be used as PVC-plasticizers

Epoxidation of vegetable oils under microwave irradiation

This paper presents a study of the epoxidation of vegetable oil in an isothermal batch reactor system equipped with microwave or conventional heating. The epoxidation reaction was performed by peroxycarboxylic acid formed in situ from carboxylic acid and hydrogen peroxide. It was demonstrated that microwave irradiation can accelerate the epoxidation velocity when the continuous phase is aqueous, which is not transparent to microwave. This tendency was observed for peroxyacetic and peroxypropionic acids.

Kinetics of Epoxidation of Vegetable Oils Catalyzed by Formic Acid, Peroxophosphatotungstate and Methyltrioxorhenium

The kinetics of epoxidation of vegetable oils by traditional route (formic acid) or novel routes (peroxophosphatotungstate, methyltrioxorhenium) with hydrogen peroxide (H2O2, 30 wt. %) were investigated. The mathematical models describing the kinetics of epoxidation were developed. Using a linear fit method, kinetic parameters were estimated by fitting experimental data. The activation energy of the epoxidation reaction decreased in the following order: peroxophosphatotungstate > formic acid > methyltrioxorhenium. Other oils were also investigated under the same conditions. Results showed that the activation energy of epoxidation was in the order; rapeseed oil < fatty acid methyl ester < soybean oil < sunflower oil. Thermodynamic parameters of the epoxidation of vegetable oils were also obtained.

Immobilized molybdenum acetylacetonate complex on montmorillonite K-10 as catalyst for epoxidation of vegetable oils

Heterogeneous catalyst was obtained by the direct immobilization of molybdenum compound on montmorillonite K10 clay. The resultant solid was characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffractometry (XRD), scanning electron microscopy coupled in a energy dispersive X-ray spectrometer (SEM-EDS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller and Barret–Joyner–Halenda isotherms (BET/BJH), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis-DRS) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The catalyst was tested for the epoxidation of both soybean and castor oils, using tert-butyl hydroperoxide (TBHP) as oxidizing agent. After the first use, the immobilized catalyst showed an enhanced activity and also catalytic stability in recycling experiments. The best results for epoxidation reactions concerning castor oil were observed under conditions of 80 °C for 24 h (100% conversion and 75% selectivity) and catalytic reuse.

Epoxidation of jatropha oil using heterogeneous catalysts suitable for the Prileschajew reaction: Acidic resins and immobilized lipase

Sulphonated polystyrene resins, Nafion-silica and immobilized lipase were used as heterogeneous catalysts for the epoxidation of jatropha oil. Immobilized lipase showed ca. 100% conversion and 100% epoxide selectivity at 24 h. However, this catalyst cannot be reused because it completely deactivates after one use. For the selective epoxidation of vegetable oils with percarboxylic acids the most crucial feature to prevent the formation of glycols is to minimize the exposure of the epoxide to the acidic sites of the catalyst. This can be achieved using resins with a high level of cross-linking and with low external surface area. Activity can be increased by increasing the strength of the acid sites. Amberlite IR-120 was the best heterogeneous catalysts, yielding ca. 90% conversion and 70% epoxide selectivity, both stable through five re-uses. Dowex 50WX2 afforded the production of glycols with more than 90% selectivity at conversions of ca. 90%.

Novel process windows – Concept, proposition and evaluation methodology, and intensified superheated processing

The concept of novel process windows has recently been proposed by Hessel (2009) and his major processing variant, the pressurised superheated processing, is the topic of several recent reviews in the field. Different from process intensification and micro-process technology enhancing mass and heat transfer to reveal intrinsic kinetics, novel process windows aim at speeding up kinetics, i.e. dramatically reducing reaction time. This idea is taken up more and more in micro-process technology, but origins as well from the encased processing practised since longer in microwave organic chemistry. Novel process windows as highly intensified processing approach tends to fully exploit the kinetics (reactivity) while maintaining selectivity at an acceptable level through use of harsh conditions, rather than to domesticate chemistry that is common practice in the process chemistry of the past. Reaction rates can be accelerated by orders of magnitude and reaction times shrink from hours to minutes and seconds. The accompanied large increase in productivity is a further cornerstone in making micro-process technology a competitive concept as opposed to the economics of scale, practised since decades in production chemistry aiming at increasing the vessel size more and more. Different to the content provided in recent reviews, this compilation focuses on the process chemistry potential of superheated processing (while still providing a short summary on the other processing options), a methodology how to find novel processing conditions and how to evaluate these. Two reactions, the Swern–Moffatt oxidation and the Claisen rearrangement, are discussed in detail, since these are ideal candidates for high-temperature investigations due to their eminent synthetic importance and well-known kinetics. As a practical reaction example with industrial guidance of a running European Project, the epoxidation of vegetable oils, the new methodology is exemplified beyond the level of the organic chemists’ descriptions given so far.

Epoxidation of Vegetable Oils and Fatty Acids: Catalysts, Methods and Advantages

Epoxidation of Vegetable Oils and Fatty Acids: Catalysts, Methods and Advantages

Optimization of the reaction parameters of epoxidation of rapeseed oil with peracetic acid

AbstractBACKGROUND: The epoxidation of vegetable oils has been a subject of interest for many years; epoxidized oils are frequently used as plasticizers and as renewable materials for the manufacture of alcohols, glycols and many other complex compounds with excellent antioxidant and antifriction properties. In this work the epoxidation process of rapeseed oil (RO) with peracetic acid generated in situ by the reaction of 30 wt% hydrogen peroxide and acetic acid has been studied. Optimization studies were performed by application of a statistical experimental design method utilizing a rotatable‐uniform design.RESULTS: The significant parameters for the RO epoxidation process were established as temperature, molar ratio of hydrogen peroxide to rapeseed oil, molar ratio of acetic acid to rapeseed oil and reaction time. The process description was based on five response functions: iodine number, epoxy number, conversion, yield and selectivity. The highest values of all functions with the exception of selectivity were achieved for the same values of parameters: temperature 65 °C, molar ratio of hydrogen peroxide to RO 11.1:1 mol mol−1, molar ratio of acetic acid to RO 1.89:1 mol mol−1 and reaction time 6 h.CONCLUSION: In summary, these optimum parameters allow one to obtain epoxidized rapeseed oil with a yield of 66.2 mol% at an oil conversion of 91.0 mol% in mild and relatively safe conditions. The epoxy number of the product was 0.207 mol per 100 g, whereas the iodine number was 0.027 mol per 100 g. Copyright © 2010 Society of Chemical Industry