| Abstract: | Using dialkyl carbonates as reagents for lipase‐catalyzed transesterification, the reaction is driven by the evolvement of carbon dioxide as the co‐product and thus no longer an equilibrium reaction. Therefore this transesterification method is faster and quantitative conversions can be obtained. Short‐chain dialkyl carbonates, like other short‐chain esters, are also suitable solvents for seed oil extraction. Thus, extraction and transesterification can be combined in a single reaction. This reaction, called reactive extraction, was carried out in a standard Soxhlet apparatus with rapeseed, linseed and calendula seed as the raw materials and with dimethyl and diethyl carbonate as extraction solvent and transesterification reagent at the same time. Fatty acid methyl esters and ethyl esters respectively were obtained with higher yields than those achieved by conventional two step extraction / transesterification. In the case of linseed fatty acid esters and especially calendula seed fatty acid esters, the iodine values of the products obtained by one‐pot‐two‐step reactive extraction were significantly higher. |
