Reactive extraction of propionic acid by using tri-octyl amine in edible oils.

Due to high demands for the production of propionic from fermentation broth, the reactive extraction of the acid using green and non-toxic and microorganism-friendly diluent instead of toxic and harmful conventional organic solvents is considered in this work over the temperature range of 298–318 K. Soybean oil and rice bran oils which reduce the toxic effect of the used reactive extractant tri-octyl amine (TOA) are used as the diluents. The achieved overall distribution coefficient and extraction efficiency are found higher in soybean oil (0.73, 42.25%, respectively) as compared to rice bran oil (0.66, 40.00%, respectively). Due to the low cost and microorganism-friendly nature, soybean and rice bran oils are anticipated to use in bio-refinery industries to recover propionic acid from fermentation broth. The estimated K D chem / K D phy ratio greater than 1.0 shows that the extraction of the acid is dominated by the chemical extraction at the relatively higher initial concentration of TOA. The chemical reaction equilibrium constant, K E (m : n) , and complexation stoichiometries m and n are determined by applying differential evaluation (DE) technique. K E m : n is found higher in the case of soybean oil. Despite the loading ratio Z < 0.5, m is found greater than 1.0. The concentration of the complex [ H A m S n ] org is higher in soybean oil than rice bran oil. The negative enthalpy change due to the complexation reaction shows that it is exothermic. The positive entropy changes due to only mass transfer direct to supply external energy to mix the studied immiscible phases. [ABSTRACT FROM AUTHOR]