Technical Abstract: The two step syntheses of the cyclic carbonates: carbonated methyl oleate (CMO) and carbonated methyl linoleate (CML) are reported. First, synthesis of the epoxide through well precedented chemical reaction of unsaturated fatty methyl esters with hydrogen peroxide and formic acid is performed. Next, we use a carbonation reaction with a simple tetrabutylammonium bromide catalyst allowing the direct incorporation of carbon dioxide into the olechemical. The use of the higher density of supercritical carbon dioxide overcomes its low reactivity and allows the carbonation reaction to be performed overnight. Our synthesis also avoids the use of the environmentally unfriendly phosgene. The carbonated products are characterized by IR, 1H NMR, and 13C NMR spectroscopy, and studied by thermogravometric analysis (TGA). Also reported is the synthesis of a similar cyclic carbonate from the commercially available 2-ethylhexyl epoxy soyate. These carbonates show properties which may make them useful as petrochemical replacements, or as bio-based industrial product building blocks.