Separation of free fatty acids from deodorizer distillates using choline hydrogen carbonate and supercritical carbon dioxide

• Conversion of free fatty acids into choline carboxylate ionic liquid for olive oil deodorizer distillate fractionation.
• Fractionation of oil mixture tuned by combination of IL and supercritical carbon dioxide.
• Valorization of agro-industrial wastes using green technologies.

One of the main problems of deodorizer distillates is the difficulty in separating free carboxylic fatty acids (FFA) from the remaining added-value components, such as squalene. A two-step novel strategy for the valorization of olive oil deodorizer distillate (OODD) is presented, based on the use of choline hydrogen carbonate and supercritical carbon dioxide (scCO2). In the first step, the FFA present in OODD were neutralized with choline hydrogen carbonate to form choline carboxylates. The choline carboxylates obtained are of interest to the cosmetic industry. Due to their ionic character, they are insoluble in scCO2. Therefore in the second step, the reaction mixture was subjected to extraction with scCO2 at 15 MPa, 313 K and a gas flow rate of 2 ml min−1, yielding an extract with a maximum FFA content of ca. 3% (w/w). A valorization supply chain of OODD is proposed.

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