The production of biodiesel from high free fatty acid mixed crude palm oil using a two-stage process was investigated. The kinetics of the reactions was determined in a batch reactor at various reaction temperatures. It was found that the optimum conditions for reducing high free fatty acid (FFA) in MCP (8-12 wt.%/wt oil) using esterification was a 10:1 molar ratio of methanol to FFA and using 10 wt%/wt of sulfuric acid (based on FFA) as catalyst. The subsequent transesterification reaction to convert triglycerides to the methyl ester was found to be optimal using 6:1 molar ratio of methanol to the triglyceride (TG) in MCPO and using 0.6 wt.%/ vole sodium hydroxide as catalyst. Both reactions were carried out in a stirred batch reactor over a period of 20 min at 55, 60 and 65 degrees C. The concentration of compounds in each sample was analyzed by Thin Layer Chromatography/Flame Ionization Detector (TLC/FID), Karl Fischer, and titration techniques. The results were used for calculating the rate coefficients by using the curve-fitting tool of MATLAB. Optimal reaction rate coefficients for the forward and reverse esterification reactions of FFA were 1.340 and 0.682 l mol(-1) min(-1), respectively. The corresponding optimal transesterification, rate coefficients for the forward reactions of TG, diglyceride (DG), and monoglyceride (MG) of transesterification were 2.600. 1.186, and 2.3031 mol(-1) and for the reverse reactions were 0.248, 0.227, and 0.022 l mol(-1) min(-1), respectively. (C) 2011 Elsevier B.V. All rights reserved.