One-Pot Tandem Catalytic Epoxidation—CO2 Insertion of Monounsaturated Methyl Oleate to the Corresponding Cyclic Organic Carbonate

Abstract

Conversion of unsaturated fatty acids, FAMEs or triglycerides into the corresponding cyclic organic carbonates involves two reaction steps—double-bond epoxidation and CO2 insertion into the epoxide—that are generally conducted separately. We describe an assisted-tandem catalytic protocol able to carry out carbonation of unsaturated methyl oleate in one-pot without isolating the epoxide intermediate. Methyl oleate carbonate was obtained in 99% yield and high retention of cis-configuration starting from methyl oleate using hydrogen peroxide and CO2 as green reagents, in a biphasic system and in the presence of an ammonium tungstate ionic liquid catalyst with KBr as co-catalyst.

Utilization of CO2-Available Organocatalysts for Reactions with Industrially Important Epoxides

“…The utilization of tandem reactions such as the one-pot production of cyclic carbonates starting directly from biobased unsaturated fatty acids esters [8], the one-pot production of ethylene carbonate from ethylene produced by low-energy-demanding methods [2,108] or the production of HMEC from chlorinated bio-based glycerol [109] seems to be very promising for effective CO 2 fixation.…”

“…For the above-mentioned catalytic action of amine salts, the reaction mechanism based on the activation of epoxide via the protonation with amine salt in the role of Bronsted acid (HA) is proposed with subsequent anion-based epoxide ring opening. above-mentioned non-nucleophilic amines (DBU.HA, N-methylimidazole (MIM.HA), N,N-dimethylaminopyridine (DMAP.HA)) and, alongside these, even triethanolamine, pyridine and caffeine (Figure 3), are quite catalytically active in the cycloaddition of CO2 with epoxides (Table 3, Entries [3][4][5][6][7][8][9][10][11][12][15][16][17][18][19][20][21][22][23][24]. Hydrogen halides in particular are the most active in comparison with corresponding free bases [29,30,32,[37][38][39] (Table 3, Entries 3-6, 8-12).…”

“…Carbon dioxide capture and utilization (CCU technologies) has been recognized as a possible and cost-effective way to reduce worldwide greenhouse gas emissions [1][2][3][4][5][6][7][8][9][10]. The use of CO 2 as a raw material in chemical synthesis is a research area of great scientific, economic and ecological interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The abundance and benignity of carbon dioxide, which is cheap, nontoxic and nonflammable, makes it a very attractive low-cost C1-synthon in organic chemistry.…”

“…The epoxides available for carbonation can be classified according to their bound substituents as terminal epoxides (containing at least one unsubstituted CH2 group in the oxirane ring) and internal epoxides (containing substituents on both carbon atoms of the oxirane ring, Figure 1). The reaction conditions for the efficient carbonation of epoxides differ significantly, utilizing terminal (for example, glycidyl derivatives such as epichlorohydrin or glycidol and corresponding glycidyl ethers) [1][2][3][5][6][7][8][9][10][11][12][13][14]) or sterically, much more hindered internal epoxides (for example, epoxidized fatty acids and their derivatives [4,[8][9][10][11][12][13][14]). From the sustainability point of view, bio-based epoxides ideally serve as suitable reactants for the production of cyclic carbonates utilizing waste CO2.…”

“…Cyclic carbonates are used for polymer production, as electrolytes in lithium-ion batteries, polar aprotic (ethylene or propylene carbonate) or protic solvents (glycerol carbonate, etc.) and as chemical intermediates in organic synthesis [1][2][3][4][5][6][7][8][9][10][11][12][13][14] (Scheme 3).…”