Epoxidation Of Vegetable Oils Research Articles

Investigating the effect of refining parameters on acetic acid removal and the quality of crude epoxidized soybean oil

AbstractWashing crude epoxidized oil is an indispensable step for the removal of residual acetic acid and unreacted hydrogen peroxide after epoxidation. There are many studies on the epoxidation of vegetable oils but there are many discrepancies in the washing process which likely leads to water wastage, excess use of neutralizing agent, and additional processing time. Hence, this study aims to optimize the washing step by analyzing the quality of each washing step and developing a model that can predict the amount of acid removed. Soybean oil (1.5 kg) was epoxidized at 60°C for 5.5 h using Amberlite IR 120H as a heterogeneous catalyst. To determine the optimum water washing level, process parameters such as number of washing cycles (1–5), proportion of epoxidized oil to water volume (1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5), and water temperature (20, 40, and 60°C) were examined. The main responses were the residual acid value and pH of the washed epoxidized oil. Results revealed that 64% of the acid was removed after 5 washing cycles irrespective of the washing water temperature and proportion. In contrast, approximately 57% of the acid was removed in the first two washing cycles. Increasing the temperature of the water affected acid removal; with approximately 54% of acid removed at 20°C compared to 60% at 60°C. Doubling or tripling the amount of water needed above a 1:0.5 ratio did not significantly affect the amount of acid removed. The model developed was significant with a predicted R2 of 96% and a root mean square error (RMSE) of 1.1 when the model was validated at different washing scenarios. Therefore, this study shows that it is possible to significantly reduce the amount of water used and processing time while maintaining resin qualities.

Epoxidation of Vegetable Oils via the Prilezhaev Reaction Method: A Review of the Transition from Batch to Continuous Processes

Epoxidation of Vegetable Oils via the Prilezhaev Reaction Method: A Review of the Transition from Batch to Continuous Processes

Biphasic phase-transfer catalysis: epoxidation of vegetable oils by surface active ionic liquids in water

Surface-active ionic liquids (SAILs) are introduced as single-component molecular catalysts for the epoxidation of vegetable oils. The organic product phase can be separated by mechanical methods and the SAILs are recycled from the aqueous phase.

Preparing epoxidized vegetable oil from waste generated by the kapok fiber industry and assessing its thermal stabilization effect as a co-stabilizer for polyvinyl chloride

This paper describes the epoxidation of vegetable oil derived from waste kapok seeds using performic acid, which was generated in situ with sulfuric acid acting as a catalyst. The mole ratio of formic acid to double bonds varied between 0.25 and 1.00. The completion of the reaction has been verified by analyzing FTIR and NMR spectra. The resulting epoxidized kapok seed oil (EKSO) has a maximum oxirane oxygen content of 2.7%, achieved at a formic acid to double bond mole ratio of 0.5. The study has also examined the potential use of EKSO as a co-stabilizer in the presence of Ca/Zn stearate for stabilizing polyvinyl chloride (PVC). Both static and dynamic tests demonstrated that incorporating EKSO into the Ca/Zn stearate system leads to a significant increase in the thermal stability of PVC. Moreover, the effectiveness of EKSO as a co-stabilizer was found to be comparable to that of epoxidized soybean oil (ESBO). However, the use of EKSO did result in a decrease in the strength of PVC due to an increase in plasticity, although this effect was minimal at low dosages and was also observed with ESBO. On the other hand, when utilizing small doses (<2 phr), there is a tendency for flowability to decrease, but the reduction is not significant either. Overall, these findings suggest that EKSO could be a valuable co-stabilizer for PVC in industrial applications, as it enhances PVC's thermal stability without significantly compromising its mechanical and flow properties.

Catalysis for Oleochemical Platforms

AbstractThe present review articles the most recent efforts, made in the Department of Chemical Sciences of the University of Naples Federico II, in the catalytic treatment of biomasses derived from vegetable oils. The review is focused on several technologies aimed at the production of either biofuels or valuable chemicals: (i) biodiesel production; (ii) esterification to obtain high‐added value products; (iii) epoxidation of vegetable oils; (iv) glycerol ketalization; (v) oxidative cleavage of unsaturated fatty acids. The results are critically summarized to highlight the scientific activities and the main results in the field of biorefinery concept.

In-Depth Kinetic Modeling and Chemical Analysis for the Epoxidation of Vegetable Oils in a Liquid–Liquid–Solid System

A heterogeneous catalyst for producing epoxidized vegetable oils, an important intermediate in the production of non-isocyanate polyurethanes, is essential for product separation and for decreasing the side-reaction, i.e., ring-opening reaction, via the Prileschajew method. The development of reliable kinetic models considering key variables for both phases and the mass transfer phenomena is missing in the literature. The reaction pathway for the ring-opening reaction is also under debate. Therefore, we studied the kinetics of epoxidation of cottonseed oil by perpropionic acid over the solid acid catalyst amberlite IR-120. An in-depth kinetic model was developed by using Bayesian inference. The reaction pathway for the ring opening was investigated. Propionic acid, a weak acid, allows for a decrease in the oxirane ring-opening side reaction.

Epoxidation kinetics of vegetable oil in micellar medium by reaction calorimetry

The kinetics of vegetable oil epoxidation in the presence of different families of surfactants was conducted in an RC1 calorimetric reactor, to explore the micellar effect on the overall rate and kinetic parameters of the reaction. The reaction time was reduced by 2 to 3 hours compared to that obtained in the absence of micelles. A kinetic model is proposed whose parameters are estimated using a method based on the reconstruction of the thermal power profile released by the synthesis. The activation energy of the epoxidation reaction is 44.08 kJ. Safety parameters (MTSR, MTT, TD24) are also determined to study the possibility and severity of thermal runaway.

Opportunities and Emerging Challenges of the Heterogeneous Metal-Based Catalysts for Vegetable Oil Epoxidation

Opportunities and Emerging Challenges of the Heterogeneous Metal-Based Catalysts for Vegetable Oil Epoxidation

Aquivion perfluorosulfonic superacid as an effective catalyst for selective epoxidation of vegetable oils.

The acid-promoted epoxidation of vegetable oils was studied using a variety of acidic ion exchange resins as heterogeneous acid catalysts. Quantitative and selective epoxidation of a series of vegetable oils with different composition of saturated, mono-, di- and tri-unsaturated fatty acids was obtained upon identification of the more efficient catalyst and experimental conditions. Furthermore, optimized reaction conditions were successfully applied to the epoxidation of a waste cooking oil, thus extending our procedure to the valorization of a biowaste, an area of increasing importance within a more sustainable society. The use of quantitative 1HNMR besides making accurate evaluation of the amounts of reagents to be employed and of the selectivity, allowed facile and rapid quantification of mono-, di- and tri-epoxides, thus providing an indirect indication on the fatty acid composition of the vegetable oils, even in the presence of very low quantities of linolenic acid.

A new perspective on vegetable oil epoxidation modeling: Reaction and mass transfer in a liquid–liquid–solid system

AbstractA rigorous mathematical model was developed for a complex liquid–liquid–solid system in a batch reactor. The approach is general but well applicable for the indirect epoxidation of vegetable oils according to the concept of Nikolaj Prileschajew, implying in situ prepared percarboxylic acids as epoxidation agents. The model considers intra‐ and interfacial mass transfer effects coupled to reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction–diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e., fatty acid epoxidation) illustrated the power of real multiphase model in epoxidation processes. The proposed modeling concept can be used for optimization purposes for applications, which comprise a complex water–oil–solid catalyst system.

Kinetics of Grape Seed Oil Epoxidation in Supercritical CO2

The epoxidation of grape seed oil in supercritical CO2, to the best of our knowledge, has been only superficially described in the literature, apart from a short communication and our own previous published work on the topic. In this work, a thorough study of the performance of the supercritical epoxidation of grape seed oil is performed in a wide range of conditions, and the kinetic parameters of the supercritical epoxidation of vegetable oils are reported for the first time in the literature. The experimental work has covered a 40–60 °C temperature range at 150 bar, sampling during a period of 48 h. The nature and extent of the side reactions and secondary products obtained have been evaluated, being hydrolysis products and their oligomerization derivatives the major by-products. Reaction rate constants (10−2 h−1 order) and activation energy parameters were finally calculated from the experimental conversion and epoxy yield data to establish the effect of temperature on the kinetics of the process.

Model Discrimination for Hydrogen Peroxide Consumption towards γ-Alumina in Homogeneous Liquid and Heterogeneous Liquid-Liquid Systems

The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

Influence assessment of inlet parameters on thermal risk and productivity: Application to the epoxidation of vegetable oils

The influence of inlet parameters on the production and thermal risk of complex chemical systems can be cumbersome to evaluate. To determine the optimum safe operating conditions, one needs to solve complex differential equations derived from energy and material balances. This robust approach cannot be made on-site, and it is essential to propose simplest tools to evaluate rapidly the performance and safety of some operating conditions. This is the aim of this paper that establishes explicit relationships between the production and thermal risk parameters, and the inlet parameters. In addition, it also proposes a Pareto chart that can be used to make the tradeoff between safety and performance. Such relationships and chart were developed for the production of epoxidized cottonseed oil under isoperibolic and semi-batch mode. The kinetic model developed by Zheng et (Zheng et al., 2016). was used. First, a numerical approach, i.e., least square method, was used to find explicit relationships between thermal risk parameters, production parameters and six inlet parameters. The use of such an approach allows a better understanding of this process. Second, safety and performance indicators are proposed and discussed to evaluate the operating conditions thanks to a simple and intuitive schema. Besides, this approach can be used to find the optimum conditions more rapidly.

OBTAINING AND PROPERTIES OF COMPOSITIONS OF UREA GREASES AND THEIR COMPONENTS ON THE BASIS OF VEGETABLE OILS

Background. In recent years, requirements for the properties of lubricants and their components are increasing. Attention is paid to the impact of lubricants on the environment. Urea greases fully meet the high requirements for the properties of lubricants. The development of greases of this class and vegetable oil-based additives should solve the environmental problems of their use. Objective. The purpose of the paper is development of urea greases and their components using raw materials of plant origin. Methods. A number of protective additives to lubricants were obtained by epoxidation of vegetable oils and introduction of nitrogen-containing fragments on the carbonyl group and epoxy ring. Amidation of triacylglycerides of vegetable oils with ethylenediamine synthesized monoaminoamides of fatty acids of linear structure. Urea thixotropic systems are synthesized by the interaction of polyisocyanate with fatty acid monoaminoamides in petroleum oil. Synthesized additives in various quantities were introduced into the composition of the investigated products in order to check the operational properties of the finished greases. Results. The obtained greases are characterized by a high level of mechanical and colloidal stability. Their composition and chemical structure were established by a set of spectrometric methods of analysis. The upper temperature limit of application of the synthesized urea in the range of 150–200 °С is established by the method of derivatographic analysis. It is established that the combination of urea thickener and vegetable oil-based additives allows obtaining urea greases with high thermal stability, improved protective and antioxidant characteristics. The use of environmentally friendly oleochemical products in the composition of the thickener and lubricant additives improves the biodegradability of the developed grease composition. Conclusions. It is shown that the proposed series of vegetable oil transformations allows obtaining ready-made compositions of urea greases and their components using raw materials of natural origin. The obtained products have satisfactory operational properties and according to some indicators industrial analogues prevail. This allows us to recommend the developed urea oils as substitutes for commercial products.

Comparative Study of Methods of Chemical Modification of Dehydrated Castor oil for Synthesis of Biolubricant

Vegetable oil blends are the emerging alternative feedstocks, which are being used to synthesize environment friendly lubricants. This work focuses on the Comparison of the methods of chemical modification, which are used for the biolubricant synthesis and also compares the resultant behaviour characterized on their thermal stability and viscosity. The biolubricant products are synthesized using two chemical modification methods. Method 1: Epoxidation of vegetable oil followed by transesterification of epoxidized oil. Method 2: Preparation of methyl esters (Transesterification) followed by epoxidation of methyl esters. Biolubricant derived from method 1 shows better thermal stability (Tonset = 338 ºC) compared to method 2 (Tonset = 205 ºC). The viscosity indices and pour point values of the products were found to be 222; 4.6 ºC and 216; 6.0 ºC, respectively. Thus, the biolubricant derived from first method showed better physio-chemical properties and were comparable and a blend of non edible oil and waste cooking oil acts as potential basestock for biolubricant synthesis.

CFD Modeling of Spatial Inhomogeneities in a Vegetable Oil Carbonation Reactor

Fossil materials are widely used raw materials in polymerization processes; hence, in many cases, the primary goal of green and sustainable technologies is to replace them with renewables. An exciting and promising technology from this aspect is the isocyanate-free polyurethane production using vegetable oil as a raw material. Functional compounds can be formed by the epoxidation of vegetable oils in three reaction steps: epoxidation, carbonation, and aminolysis. In the case of vegetable oil carbonation, the material properties vary strongly, with the composition affecting the solubility of CO2 in the reaction mixture. Many attempts have been made to model these interactions, but they generally do not account for the changes in the material properties in terms of spatial coordinates. A 2D CFD model based on the combination of the k-ε turbulence model and component mass balances considering the spatial inhomogeneities on the performance of the reactor was created. After the evaluation of the mesh independence study, the simulator was used to calculate the carbonation reaction in a transient analysis with spatial coordinate-dependent density and viscosity changes. The model parameters (height-dependent mass transfer parameters and boundary flux parameters) were identified based on one physical experiment, and a set of 15 experiments were used for model validation. With the validated model, the optimal operating temperature, pressure, and catalyst concentration was proposed.

Enhanced epoxidation of soybean oil by novel Al2O3–ZrO2–TiO2 solid acid catalyst

This study aims to develop highly efficient, recyclable solid catalysts for the epoxidation of vegetable oils. An Al2O3–ZrO2–TiO2 solid acid catalyst was prepared by a co‐precipitation/impregnation method and characterised through scanning electron microscopy, energy‐dispersive spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, Fourier‐transform infrared and nitrogen adsorption–desorption analyses. The solid acid catalyst with a high surface area and typical slit pore adsorption was successfully synthesised. Al2O3–ZrO2–TiO2 also exhibits high stability and improved catalytic efficiency in the epoxidation of soybean oil. An oil conversion rate of 86.6%, which is higher than that of conventional catalysts, was obtained with a catalyst loading of 0.8 wt% and was maintained at 76.6% even after recycling the catalyst three times. The performance of the solid catalyst was slightly superior to that of H2SO4. Therefore, this novel catalyst may potentially be applicable in catalysing soybean oil epoxidation.

Use of semibatch reactor technology for the investigation of reaction mechanism and kinetics: Heterogeneously catalyzed epoxidation of fatty acid esters

Heterogeneously catalyzed epoxidation of vegetable oils by hydrogen peroxide represents a greener route for the production of epoxides and a thermally safer reaction route compared to the classical Prileschajew epoxidation approach. The epoxidation kinetics of the heterogeneous system formed by aluminium oxide catalyst, hydrogen peroxide and methyl oleate as a model compound was studied with semibatch experiments in laboratory scale. It was found that semibatch operation improved the performance significantly compared to classical batch operation, a low and constant volumetric flowrate of hydrogen peroxide increased the final oxirane yield considerably. A semibatch reactor model and a kinetic model were developed, featuring the reaction temperature, the reactant molar ratio, the catalyst loading and the mass flow rate as the most significant experimental parameters. The mathematical model was able to well describe the experimental data. The approach can be applied to other liquid–solid catalyst systems in future in order to optimize the semibatch operation policy for complex reaction systems.

Analysis and optimization of grape seed oil epoxidation in supercritical CO2

In this work, it is proposed to check the viability of the epoxidation process of grape seed oil under supercritical conditions, select and optimize the ratios of the different reagents and/or additives that take part in it. Different experiments were performed involving oil, hydrogen peroxide, CO2 (as the supercritical fluid), sodium bicarbonate and different phase transfer catalysts (PTC) as enhancers for the performance. Operating conditions were set in 150 bar, 40 °C and 15 h. Subsequently, a statistical study of the influence of each of the reagents on the yield was carried out. Finally, it was possible to reach 8.31 % yield by means of the selection of an optimal PTC. This is the first approach reported to the epoxidation of vegetable oils through the utilization of scCO2 not only as a solvent but also as a reactant, using several PTCs and analyzing its effect and that of epoxy agents and enhancers.

Sustainable Synthesis of Epoxidized Cynara C. Seed Oil

The use of non-edible vegetable oils to produce oleochemicals has been attracting more attention in recent years. Cardoon seed oil, derived from the Cynara C. plant, growing in marginal and contaminated lands, represents a non-edible alternative to soybean oil to obtain plasticizers through epoxidation reaction. The use of hydrogen peroxide as oxidant and in the presence of a heterogeneous catalyst allows overcoming the limits of epoxidation with peracids. γ-alumina has been shown to have an active catalyst epoxidation reaction with hydrogen peroxide, mainly using acetonitrile as solvent. However, the use of acetonitrile as solvent is widely debated due to its hazardous character and health issues. For these reasons, the influence of solvent on the reaction was studied in this work to find a more environmentally friendly and stable solvent. The study showed that the epoxidation reaction takes place also in the absence of solvent although with lower selectivity. The type of solvent influences both the epoxidation and decomposition reactions of hydrogen peroxide. γ-valerolactone was found to be the most promising solvent for cardoon oil epoxidation reaction. This finding represents a noteworthy novelty in the field of epoxidation of vegetable oils with hydrogen peroxide, opening the way to greener and cleaner process. Finally, an optimization study showed that the most effective molar ratio between hydrogen peroxide and double bonds for better selectivity was 4.5 and the need to use the highest possible initial concentration of hydrogen peroxide (approximately 60 wt. %).