Kinetic and thermodynamic azadirachtin extraction from whole neem fine powder formulation

Abstract

Azadirachtin (Aza) has been extracted from powder neem formulation (PNF) obtained by grinding whole neem fruits with an inert material (dolomite) in a hammer mill. Initial study has been carried out to select the appropriate solvent for extraction of Aza from PNF and it is found that methanol is most suitable compare to ethanol, acetonitrile, and water. Three different particles sizes of PNF (HM0.4, HM0.8, and HM1.2) are prepared by changing the hammer mill screen and Aza has been extracted from each sample with methanol at different temperature (35°C, 40°C, 45°C and 50°C). Kinetic and thermodynamic studies have been performed and it is found that with decrease in PNF particle size, the extraction of Aza in methanol increases due to its increase in mass-transfer constant and equilibrium constant values. The extraction process follows first-order kinetics and the values of thermodynamic parameters (ΔG, ΔH, ΔS) indicate that the process is favourable, endothermic, and irreversible.