Selective epoxidation of methyl soyate over alumina-supported group VI metal oxide catalysts (original) (raw)
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Survey of several catalytic systems for the epoxidation of a biobased ester sucrose soyate
Catalysis Communications, 2018
Epoxidized sucrose soyate (ESS) is a biobased, reactive substrate useful in the production of a range of new materials. Several readily available metal catalysts for the synthesis of ESS by epoxidation of sucrose soyate (SS) with various oxidants have been surveyed, with the consideration of environmental sustainability. Among them, a methyltrioxorhenium(MTO)/H 2 O 2 system in 2-methyltetrahydrofuran solvent is identified as the most effective method with mild reaction conditions, high activity and high selectivity.
Epoxidation of soybean oil by the methyltrioxorhenium-CH 2 Cl 2 /H 2 O 2 catalytic biphasic system
Journal of The American Oil Chemists Society, 2002
We studied the methyltrioxorhenium (MTO)-CH2Cl2/H2O2 biphasic system for epoxidizing soybean oil. The reactions were optimized (reactant ratio, time, and temperature), which resulted in a better performance (higher conversion and selectivity) than those described in the literature. Total doublebond conversion and 95% selectivity were obtained in 2 h at room temperature. Furthermore, it was possible to reach desired epoxidation degrees by changing the oxidant and MTO amounts. The rhenium-epoxidized soybean oil remained stable in the absence of stabilizers for up to 30 d when stored at mild conditions.
Green Chemistry, 2019
Epoxidized vegetable oils (EVOs) are versatile building blocks for lubricants, plasticizers, polyvinyl chloride (PVC) stabilizers, and surface coating formulations. In this paper, a catalytic protocol for the efficient epoxidation of vegetable oils is presented that is based on a combination of a manganese catalyst, H 2 O 2 as an oxidant, and acetic acid as an additive. This protocol relies on the use of a homogeneous catalyst based on the non-noble metal manganese in combination with a racemic mixture of the N,N'-bis(2picolyl)-2,2'-bispyrrolidine ligand (rac-BPBP). The optimized reaction conditions entail only 0.03 mol% of the manganese catalyst with respect to the number of double bonds (ca. 0.1 wt% with respect to the oil) and ambient temperature. This epoxidation protocol is highly efficient, since it allows most of the investigated vegetable oils, including cheap waste cooking oil, to be fully epoxidized to EVOs in more than 90% yield with excellent epoxide selectivities (>90%) within 2 h of reaction time. In addition, the protocol takes place in a biphasic reaction medium constituted by the vegetable oil itself and an aqueous acetic acid phase, from which the epoxidized product can be easily separated via simple extraction. In terms of efficiency and reaction conditions, the current epoxidation protocol outperforms previously reported catalytic protocols for plant oil epoxidation, representing a promising alternative method for EVO production.
Study of Soybean Oil Epoxidation: Effects of Sulfuric Acid and the Mixing Program
Epoxidized vegetable oils are largely employed as plasticizers instead of harmful phthalates, and they can be a sustainable choice to produce lubricants and intermediates. The aim of this work is to study the reaction of soybean oil epoxidation of soybean using safer reactants. The reaction was carried out using hydrogen peroxide 34 wt % and acetic acid instead of the commonly used hydrogen peroxide at 60 wt % and formic acid to reduce the risk of detonation and corrosion. Moreover, the study focuses on the efficacy of the presence of an acid catalyst and sulfuric acid and the effect of its concentration. It was found that it is not possible to carry out the process without acid catalyst with those reactants. In addition, a proper mixing program was set up to improve the selectivity of the reaction.
Alumina-catalyzed epoxidation of unsaturated fatty esters with hydrogen peroxide
Applied Catalysis A: General, 2007
Two commercial aluminas and one produced by the sol-gel process were compared for the epoxidation of unsaturated fatty esters using anhydrous or aqueous hydrogen peroxide as oxidant and ethyl acetate as solvent. The aluminas show a good catalytic activity and excellent selectivity towards the epoxides. The sol-gel alumina was more efficient and when using aqueous hydrogen peroxide could be recycled several times. #
Catalysis Letters
In this work, a functionalized gallium metal–organic framework with active dioxo-molybdenum (VI) centers was evaluated as a catalyst in the epoxidation of soybean oil using tert-butyl-hydroperoxide as an oxidizing agent. The influence of the reaction time, temperature, and concentration of the oxidizing agent was studied, and it was demonstrated that the highest epoxide selectivity was obtained at 110 °C after 4 h of reaction (29% conversion and 91% selectivity) using a soybean oil/oxidizing agent ratio of 1/2. The stability of the metal–organic framework was confirmed by infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy EDS. The stability tests demonstrated that the catalyst could be reused in the catalytic process for the recovery of vegetable oils. Graphical Abstract
Industrial Crops and Products, 2017
Biodiesel has emerged as an alternative to partially replace diesel. However, the presence of polyunsaturated fatty acid chains, such as when using soybean oil as starting materials, is associated with several issues due to its low oxidative stability. Other issues, such as the formation of biofilms in fuel storage tanks and unsatisfactory cold properties are also major concerns during the use of biodiesel. Hence, the aim of this work is the modification of the chemical structure of soybean biodiesel in two steps: (i) epoxidation of soybean biodiesel double bonds and (ii) acetylation of the soybean biodiesel epoxide with acetic anhydride, using a heterogeneous catalytic system. The catalyst used for acetylation step was tin oxide supported on alumina. The catalytic system activity was evaluated using different temperature, catalyst/substrate ratio and different anhydrides. Oxidative stability, thermal analysis and anti-microbial activity were evaluated. The products structures were confirmed by infrared and nuclear magnetic resonance. The results show yields up to 98% of the desired product − diacetylbiodiesel in 10 h and 15% catalyst (w/w). The catalyst could be recycled up to four times with minor activity loss. After acetylation, it was observed an increase in both oxidative stability and biostatic activity. However, the freezing point did not change.
Epoxidation Reaction of Soybean Oil: Experimental Study and Comprehensive Kinetic Modeling
Industrial & Engineering Chemistry Research, 2020
Epoxidized soybean oil (ESO) has been considered to be a green alternative to replace petroleum-based substances as a plasticizer for polyvinyl chloride (PVC). ESO is usually produced in a biphasic reaction system, in which hydrogen peroxide reacts with a carboxylic acid in the aqueous phase to generate an organic peracid that migrates to the organic phase and reacts with the soybean oil to produce ESO. The present study includes experimental data obtained in a previous work, to prepare ESO from soybean oil in a 4 h reaction time under different conditions, with single addition of the reactants and in the absence of catalysts. The paper also proposes a more robust model to predict the effects related to the hydrogen peroxide and formic acid amounts, the stirring speed, the thermostatic bath temperature and the apparent kinematic viscosity of the system. The experimental results were used to fit a kinetic model for this system,
Soybean Oil Epoxidation: Kinetics of the Epoxide Ring Opening Reactions
Processes, 2020
The epoxide ring opening reaction (ROR) can be considered as the most important side reaction occurring in the epoxidation of soybean oil reaction network. This reaction consistently reduces the selectivity to epoxidized soybean oil (ESBO). The reaction is also important for producing polyols and lubricants. In this work, the reaction was studied in different operative conditions to evaluate the effect on ROR rate respectively: (i) The Bronsted acidity of the mineral acid (H2SO4 or H3PO4), used as catalyst for promoting the oxidation with hydrogen peroxide of formic to performic acid, that is, the reactant in the epoxide formation; (ii) the concentration of the nucleophilic agents, normally present during the ESBO synthesis like HCOOH, HCOOOH, H2O, H2O2; (iii) the stirring rate that changes the oil–water interface area and affects the mass transfer rate; (iv) the adopted temperature. Many different kinetic runs were made in different operative conditions, starting from an already ep...
Enhanced Advances in Epoxidation of Vegetable Oils
Vegetable oils are among the most encouraging sustainable raw materials due to their prepared accessibility, intrinsic biodegradability, and their numerous flexible operations. In light of the expansion in natural issues like waste exchange issues, non-biodegradable resources, greenhouse effect, and so on and the diminishment of petroleum oil resources, reasonable oils from vegetable inception have transformed into a basic issue. The ointments from inexhaustible resources are a fruitful reality in numerous parts of the world. Vegetable oils have numerous favorable circumstances, for example, high blaze point, high thickness record, high lubricity and low evaporative misfortune other than eco-perfect, inexhaustibility and non-danger. This paper audits the strategies that are as of late been honed for the epoxidation of vegetable oils.