Production of jatropha-ester (JO-ester) from jatropha oil (JO) under sequential direct-ultrasonic irradiation (UI) with auto-induced temperature rise followed by adding a mixture of methanol/sulfuric-acid catalyst (M/C) dose between high temperature intervals was studied. Comparisons with various doses of 5, 10, 16.6 and 25 mL at different temperature intervals of 108.9-120 degrees C, 100-120 degrees C, 85-120 degrees C and 75-120 degrees C respectively were performed. System parameters examined include: esterification times (t(E)) for UI, settling time (t(S)) after esterification and temperature (T). Properties of acid value (AV), iodine value (IV), kinematic viscosity (kV), density (rho(LO)) and water content (m(w)) of JO and JO-ester product were measured. The esterification conversion efficiencies (eta) were determined and assessed. An eta of 99.35% was obtained at temperature interval of 108.9-120 degrees C with 5 mL per dose for 20 doses and t(E) of 167.39 min (denoted as Process U120-5), which is slightly higher than eta of 98.87% at temperature interval of 75-120 degrees C with 25 mL per dose for 4 doses and t(E) of 108.79 min (noted as Process U120-25). The JO-ester obtained via sequential UI with adding doses of 5 mL possess AV of 0.24 mg KOH/g, IV of 124.77 g I-2/100 g, kV of 9.89 mm(2)/s, rho(LO) of 901.73 kg/m(3) and m(w) of 0.3 wt.% showing that sequential UI and dose at higher temperature interval can give higher reduction of AV compared with 36.56 mg KOH/g of original oil. The effects of t(S) and t(E) on AV are of minor and moderate importance, respectively. The combined effects of auto-induced temperature-rise of UI and temperature higher than boiling point of methanol used improve the mixing and esterification extent. (C) 2014 Elsevier Ltd. All rights reserved.