BACKGROUND Acrylic acid has a wide range of applications in plastic additives, textiles, sealants, adhesives, and surface coatings industries. Owing to its widespread demand, production through a biotechnological method has emerged as low‐cost, energy‐efficient, environment friendly with few challenges at downstream stage. Reactive extraction is a promising method to recover carboxylic acid, but suffers from toxicity problems of the diluent and extractant employed. Therefore, there is a need for a nontoxic extractant and diluent or a combination of less toxic extractants in a nontoxic diluent that can recover acid efficiently. In this context, reactive extraction of acrylic acid from aqueous phase was employed with tri‐n‐butyl phosphate dissolved in natural diluents soybean oil, sunflower oil, and rice bran oil. RESULTS Reactive extraction results are discussed in terms of the partition coefficient (α), dimerization constant (β), distribution coefficient (KD), extraction efficiency (η%), overall equilibrium complexation constant (KE), and loading ratio (ϕs). Higher distribution coefficient and extraction efficiency range was found in tri‐n‐butyl phosphate (TBP) + sunflower oil as 0.672 to 2.019 and 39.76 to 66.49, respectively. Average extraction efficiency was in the range 30.85 to 71.94% for soybean oil, 39.76 to 66.49% for sunflower oil, and 31.27 to 69.42% for rice bran oil with 0.366 to 1.464 mol kg−1 of tri‐n‐butyl phosphate. CONCLUSION Sunflower oil with tri‐n‐butyl phosphate showed higher extraction efficiency for the reactive extraction of acrylic acid. The order of extraction efficiency was observed as: TBP+sunflower oil > TBP+soybean oil > TBP+rice bran oil. Since evasion of direct contact of the organism with the organic phase or use of nontoxic diluents can substantially reduce toxic effects, natural oils were used in the present study. Reactive extraction results can be employed for the design of extraction columns. © 2017 Society of Chemical Industry

Optimisation of process parameters for reactive extraction of gallic acid from aqueous solution using a response surface method.

Experimental data on L/L equilibria in extraction of propionic acid (PA) from aqueous solutions by hydrophobic phosphonium ionic liquid (IL) tetradecyl(trihexyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate [C 14 C 6 C 6 C 6 P][BTMPP] and dodecane are presented. Modeling of equilibrium data indicated that extraction occurs via the same mechanism as in butyric acid extraction by this IL as well as by [C 14 C 6 C 6 C 6 P]-[decanoate]. Competitive extraction of PA and water and coextraction of PA with water are two mechanisms running in parallel, while the first one is more pronounced at lower PA concentrations and the second one dominates at higher PA concentrations. Experimental values of IL loading by PA and water in systems with ionic liquid [C 14 C 6 C 6 C 6 P][BTMPP] in equilibrium were successfully correlated by a model developed in our previous work. Good fit of data confirms a more general validity of this model. Stability constants of PA-IL complexes calculated by the model indicate that the affinity of PA to IL is lower compared to butyric acid but higher compared to lactic acid. Although PA-IL bonds are much weaker than butyric acid−IL bonds, the viscosity of equilibrium organic phases after PA extraction by IL is almost the same as in phases after butyric acid extraction.

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