Synthesis of bio-based cyclic carbonate from vegetable oil methyl ester by CO2 fixation with acid-base pair MOFs

Bio-based five-membered cyclic carbonates were synthesized from renewable O-acetyl methyl ricinoleate that from crops and CO2 via two steps and the products after each reaction step were characterized by fourier transform infrared spectroscopy. For the acid-catalyzed process, O-acetyl methyl ricinoleate epoxidation of unsaturated double bonds was accomplished using lipase as a sustainable replacement. The effect of different experimental conditions, including the solvent, initiator types, initiator ratios, enzyme amount, reaction temperature, and reaction time, on epoxide conversion was analyzed. O-acetyl methyl ricinoleate conversion reached 95 % under the optimized reaction conditions and the resulting epoxide was subsequently reacted with CO2 using the acid-base pair UiO-66-NH2 to produce cyclic carbonate. CO2 adsorption and fixation occurred simultaneously due to the use of bifunctional UiO-66-NH2 and epoxide conversion reached 94.4 % with CO2 using UiO-66-NH2. The substrates applicability was tested after each step and it was found that more than 92 % of the fatty acid methyl esters were converted into their corresponding epoxides and more than 90 % epoxide conversion occurred, with the exception of epoxy methyl linolenate (85.4 %) due to the presence of multiple double bonds in methyl linolenate. These results demonstrate this reaction scheme can be efficiently adopted for vegetable oil methyl esters.