Epoxidation of unsaturated fatty acid ester promoted by imidazolium acidic ionic liquids: An unexpected selectivity phenomena

Abstract

Epoxidation of linseed oil fatty acid ethyl esters promoted by a series of functionalized imidazolium ionic liquids was studied. In this reaction acidic imidazolium ILs behave not only as an acid catalysts but also play an additional role as a specific activator for the reaction of epoxidation of unsaturated fatty derivatives in H 2 O 2 /formic acid oxidation system. The obtained results indicate that the hydrogen-bonding interaction of imidazolium cation with epoxide group influences the selectivity of the epoxidation reaction. In particular, the presence of unprotected weak "acid" C2-H proton significantly lowers the selectivity to hydroxyl derivatives. The obtained results also point to another example of specific polyfunctionality of ILs, especially imidazolium one, used as surfactants and process activators.

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

“…1564 The micellar role of acidic ILs has been nicely evidenced in the epoxidation of linseed ethyl ester. 1565 The tantalum-based peroxocarbonate IL [P 4,4,4,4 ] 3 [Ta(η 2 -O 2 ) 3 (CO 4 )], generated in situ in pressurized CO 2 and H 2 O 2 , catalyzes the quantitative epoxidation of several alkenes. 1566 Carboxylic acid coordinated mononuclear peroxoniobatebased ILs, such as [C 4,4,4,4 N][NbO(OH) 2 (lactic acid)], are highly efficient and recyclable catalysts for the epoxidation of various olefins and allylic alcohols with H 2 O 2 as an oxidant under mild conditions.…”

“…And most probably ionic oxidoperoxido-molybdenum­(VI) complexes associate with imidazolium, pyridinium, and ammonium cations and showed promising catalytic epoxidation activity based on the model reaction of cis -cyclooctene with tert -butyl hydroperoxide as oxidant . The micellar role of acidic ILs has been nicely evidenced in the epoxidation of linseed ethyl ester …”

Synthesis of Solketal Ethers as Cold Flow Improver for Palm‐Based Biodiesel

“…In the search for an alternative synthetic method, we envisaged mild reaction conditions, a solvent‐free approach, and the use of a non‐toxic catalyst. Phase transfer catalyst (PTC), which accelerates reactions between reactants in different phases has been widely used in various reactions such as esterification, [36,37] polymerization, oxidation, [38] hydrolysis, and etherification [39–41] that are crucial for various industries including oleochemicals [42] …”

“…[35] In the search for an alternative synthetic method, we envisaged mild reaction conditions, a solvent-free approach, and the use of a non-toxic catalyst. Phase transfer catalyst (PTC), which accelerates reactions between reactants in different phases has been widely used in various reactions such as esterification, [36,37] polymerization, oxidation, [38] hydrolysis, and etherification [39][40][41] that are crucial for various industries including oleochemicals. [42] The use of PTC in etherification of more reactive glycerol derivatives such as glycidol and epichlorohydrin as precursor has been investigated for synthesis of glycidyl ether, [42,43] and monoalkyl glycerol ether (MAGE).…”