Biocatalytic Epoxidation Pathway of Oils in Sponge‐Like Ionic Liquids Toward CO 2 ‐Derived Cyclic Carbonate Synthesis

A sustainable chemo‐enzymatic synthesis of poly(cyclic carbonate)s from CO 2 and renewable oils is reported for the first time using sponge‐like ionic liquids (SLILs) such as hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C 16 tma][NTf 2 ]) as a monophasic reaction medium. The process integrates biocatalysis and IL technologies in two sequential steps. In the first step, a lipase catalyzes the in situ formation of peracids from free‐fatty acids (FFAs), such as oleic acid, using urea hydrogen peroxide (UHP) as a solid oxidant. These peracids spontaneously epoxidize the CC double bonds of FFAs (oleic or linoleic acid) and oils (e.g., soybean, linseed, fish, and triolein). Thus, high epoxide yields were achieved in the SLIL medium, reaching up to 72% for soybean oil (SBO) and 92% for triolein after 6 h at 55°C. The enzyme is isolated for subsequent reuse (up to five cycles). In the second step, the synthesis of poly(cyclic carbonate)s, from previously epoxidized oils, is carried out using different halide‐based IL catalysts (e.g., tetrabutylammonium bromide, [TBA][Br]), reaching up to 54% carbonated SBO yields after 72 h at 100°C and 1 MPa CO 2 . UHP is an efficient oxidant for the lipase‐catalyzed epoxidation, while the urea byproduct can promote cyclic carbonate formation without the direct use of CO 2 .