The reaction between different carboxylic acids and iron was performed by monitoring the amount of iron dissolved in oil through the formation of the iron carboxylate and by the product distribution in the gas phase. It was found that the solubility of the given iron carboxylate strongly influences the concentration of iron dissolved in oil. At temperatures higher than 300 degrees C, however, the iron carboxylate thermally decomposed and, therefore, the dissolved iron underestimates the acid corrosion potential. On the other hand, the accumulated molar amount of hydrogen gas becomes an alternative way to estimate the carboxylic acid corrosion potential. (c) 2006 Elsevier Ltd. All rights reserved.