Abstract:

Oil extraction was performed in aqueous HCl, H2SO4 and H3PO4 solutions with n-hexane (C6H14) at 30, 40, 50 and 60 oC using 10 gr of sunflower seeds over 1 h with 10-min. sampling intervals. The optimum acid concentration was wt. 10% for each acid, and the highest oil yield was obtained in the extraction procedure with n-hexane containing H2SO4. The extraction process was observed with regard to the percent oil yield versus time, and the reaction order was found to be first-order kinetics by the differential method. The activation energy for the oil extraction kinetics of sunflower seeds with 10% H2SO4 was found to be Ea=4.2 kJmol-1, and the activation thermodynamic parameters at 60 oC were DH \neq =1.43 kJmol-1, DS \neq=-309.3 Jmol-1K-1 and DG \neq =104.4 kJmol-1. The enthalpy value was DH=11.2 kJmol-1, and the other thermodynamic parameters at 60 oC were DS=36.75 Jmol-1K-1 and DG= -1.07 kJ mol-1.

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