Epoxidation Of Unsaturated Fatty Esters Research Articles

Synthesis of peroxophosphotungstate immobilized onto polymeric support as heterogeneous catalyst for the epoxidation of unsaturated fatty esters

Phosphotungstate-based catalysts are efficient catalyst for epoxidation of unsaturated fatty methyl esters but the separation and the reuse of the catalyst are extremely difficult. For that reason, we have prepared different polyoxotungstate catalyst supported onto amphiphilic resins by anionic exchange. We have tried to control the resin amphiphilic characters by varying the imidazole group nature, as well as the spacer linker on the support. This heterogeneous catalyst exhibits excellent activity in the epoxidation of methyl-9,10-octadecenoate with aqueous H2O2 and can be easily recycled without loss of performance.

Selective epoxidation of unsaturated fatty esters over peroxophosphotungstic catalysts (POW) under solvent free conditions: Study of the POW catalyst's mechanism

Methyl oleate epoxidation with a peroxophosphotungstate (POW) catalyst was performed under solvent free conditions. After underlying a synergistic effect of hydrogen peroxide and the dioxygen flow to obtain a total epoxide yield, new investigations were realized to understand this effect. The POW catalyst mechanism was studied using labeled oxygen flow and radical traps. We concluded that the reaction occurs in two parallel ways, a major one thanks to a concerted mechanism and a minor radicalar one leading to the formation of methyl stearate alcohol and diol intermediates. Oxygen flow is only necessary to perform the radicalar way.

Alumina-catalyzed epoxidation of unsaturated fatty esters with hydrogen peroxide

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.

Epoxidation of unsaturated fatty esters over large-pore Ti-containing molecular sieves as catalysts: important role of the hydrophobic–hydrophilic properties of the molecular sieve

M. A. Camblor, A. Corma, P. Esteve, A. Martínez and S. Valencia, Chem. Commun., 1997, 795 DOI: 10.1039/A700448F

Ultrasound-assisted epoxidation reaction of long-chain unsaturated fatty esters

Ultrasound (20 kHz)-assisted epoxidation of unsaturated fatty esters with m-chloroperoxybenzoic acid (MCPBA) in water was successfully carried out in less than 30 min. Epoxidation of unsaturated fatty esters containing an internal ethylenic system was more readily accomplished than with substrates containing a terminal ethylenic bond. The rate of epoxidation of the same unsaturated fatty esters using magnesium monoperoxyphthalate in aqueous ethanol was much slower than reactions with MCPBA.

Epoxidation of unsaturated fatty esters in argentation chromatography

Absorption chromatography of unsaturated esters on silver ion-silica gel columns leads to the formation of epoxides, if solvents containing peroxides are used. With small samples of radioactive esters the epoxide is formed in proportion so large that subsequent analytical procedures will reveal the epoxide, to the possible confusion of the investigator. Data on the behavior of epoxides of common unsaturated fatty esters in TLC and GLC are presented.

Theory and practice of resin‐catalyzed epoxidation

SummaryCommercial polystyrene sulfonic acid resins have been shown to be effective in catalyzing epoxidation of unsaturated fatty esters with hydrogen peroxide and acetic acid because they catalyze peracid formation but do not promote by‐product formation when used under proper conditions. Special resins with less cross‐linkage have been shown to yield mostly by‐products.Best catalyst life has been obtained with a special resin prepared with a low metal content.A continuous process based on the cascade principle has been demonstrated in the laboratory. The problem of resin re‐use for both continuous and batch processes can best be solved by using the optimum 10–15% based on oil weight and by replacing about 10% of the resin after each use.