Browsing by Subject "Sustainable chemistry"

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    A green chemo-enzymatic approach for CO2 capture and transformation into bis(cyclic carbonate) esters in solvent-free media
    (American Chemical Society, 2024-10-02) Ruiz, Francisco J.; Velasco, Francisco; Porcar, Raul; Garcia Verdugo, Eduardo; Villa Aroca, Rocío; Lozano Rodríguez, Pedro; Nieto Cerón, Susana; Bioquímica y Biología Molecular B e Inmunología
    A sustainable approach for CO2 capture and chemo-enzymatic transformation into bis(cyclic carbonate) esters from CO2, glycidol and organic anhydrides under solvent-free conditions has been demonstrated. The chemo-enzymatic process is based in two consecutive catalytic steps, which can be executed through separated operations, or within a one-pot combo system, taking advantage of the synergic effects that emerge from integrating ionic liquid (ILs) technologies and biocatalysts. In a first step, lipase-catalyzed transesterification and esterification reactions of different diacyl donors (e.g. glutaric anhydride, succinic anhydride, dimethyl succinate, etc.) with glycidol in solvent-free under mild reaction conditions (70 °C, 6 h), producing the corresponding diglycidyl esters derivatives up to 41% yield. By a second step, the synthesis of bis(cyclic carbonate) esters was carried out as results of the cycloaddition reaction of CO2 (from an exhausted gas source, 15% CO2 purity) on these diglycidyl esters, catalyzed by the covalently attached 1-decyl-2-methylimidazolium IL (Supported Ionic Liquid-Like Phase, SILLP), in solvent-free, leading up to 65% yield after 8 h at 50 °C and 1MPa CO2 pressure. Both key elements of the reaction system (biocatalyst and SILLP) were successfully recovered and reused for at least 5 operational cycles. Finally, different metrics have been applied to assess the greenness of the solvent-free chemo-enzymatic synthesis of bis(cyclic carbonate) esters here reported.
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    Clean enzymatic production of flavor esters in Spongelike Ionic Liquids
    (American Chemical Society, 2019-07-02) Alvarez, Elena; Rodríguez, José; Villa Aroca, Rocío; Gómez, Celia; Donaire, Antonio; Villa Aroca, Rocío; Lozano Rodríguez, Pedro; Nieto Cerón, Susana; Bioquímica y Biología Molecular B e Inmunología
    The biocatalytic synthesis of 16 flavor esters was carried out by the direct esterification of aliphatic acids (e.g., acetic, propionic, etc.) with an alcohol (e.g., cinnamyl alcohol, benzyl alcohol, anisyl alcohol, rac-1-phenylethanol, or rac-sulcatol) using hydrophobic ionic liquids (ILs) based on ammonium or imidazolium cations containing a long alkyl side chain (e.g., hexadecyltrimethylammonium bistriflimide, [C16tma][NTf2]) as the reaction medium. As temperature-switchable liquid/solid phases, these ILs behave as spongelike systems (so-called spongelike ionic liquids (SLILs)), which act as excellent monophasic reaction media for the lipase-catalyzed synthesis of flavor esters. Under appropriate selected reaction conditions (e.g., enzyme, substrate molar ratio, nature of the SLIL, etc.), product yields near 100% were obtained for all of the synthesized flavor esters. Because of the unique spongelike properties of these ILs, a separation protocol based on the centrifugation of the solid IL/flavor ester through nylon membranes was successfully used. By means of this approach, the clean separation of all flavor products from the solid reaction media was easily achieved, while the recovered SLIL/biocatalyst system was reused for six consecutive operation cycles with unchanged catalytic performance.