Kinetic and thermodynamic characteristics of microwave-assisted extraction for the recovery of paclitaxel from Taxus chinensis

Abstract Batch experiment studies were carried out for the microwave-assisted extraction of paclitaxel from Taxus chinensis using methanol while varying parameters such as microwave power, extraction temperature and contact time. It was possible to recover the majority of paclitaxel (∼99%) from the biomass through a singular extraction at microwave powers of 50–150 W, and temperatures of 303–318 K, within an operational time of 6 min. The kinetics data for paclitaxel extraction was in concordance with the hyperbolic and second-order models. The effective diffusion coefficient of paclitaxel (303∼318 K: 0.3801 × 10−12∼0.5062 × 10−12  m2/s, 50∼150 W: 0.2342 × 10−12∼0.2560 × 10−12  m2/s) and mass transfer coefficient (303∼318 K: 0.2709 × 10−7∼0.3623 × 10−7 m/s, 50∼150 W: 1.5110 × 10−7∼2.2227 × 10−7 m/s) increased with increasing extraction temperatures and powers. Thermodynamic parameters, such as standard enthalpy ( Δ H 0 ), standard entropy ( Δ S 0 ) and standard Gibbs free energy ( Δ G 0 ) change, were investigated, with the results indicating that the process was endothermic, irreversible, and spontaneous.