Due to the fact that n-butanol can be obtained from renewable biomass, a factorial design of experiments and a central composite design have been used to optimize the transesterification reaction of esterified oil from Crude Jatropha Curcas Oil (CJCO), choosing 1-butanol as reactive. The chosen response was the Fatty Acid Butyl Ester (FABE) yield while the studied variables were the temperature and the potassium methoxide concentration, which both have significance in the process. The FABE yield is augmented by increasing the temperature and the concentration of potassium methoxide in the transesterification reaction. Also, the transesterification reaction of CJCO was studied with four short-chain alcohols (methanol, ethanol, 2-propanol and n-butanol) at different temperatures (45-60 degrees C) and potassium methoxide concentrations (0.5-1 wt%). Finally, the transesterification reaction was carried out with methanol, ethanol, 2-propanol and 1-butanol and the most important properties fixed in the UNE-EN Standard were measured for each obtained biodiesel. (C) 2014 Elsevier Ltd. All rights reserved.