The thermal behavior of Sterculia striata oil, which is rich in fatty acids containing a cyclopropenyl ring in their chain, mainly malvalic acid (7-(2-octylcycloprop-1-en-1-yl) heptanoic acid) and sterculic acid (8-(2-octylcycloprop-1-en-1-yl) octanoic acid), is evaluated. Thermogravimetric analysis (TGA) has shown that weight loss occurs from 280 degrees C. Differential scanning calorimetric (DSC) analysis indicates two exothermic events: one related to the ring opening in cyclopropenoids fatty acids chains and another to the pyrolitic decomposition of the oil, mainly the cracking of the ester groups. H-1 NMR analysis revealed that the opening process of the cyclopropenyl ring starts at 150 degrees C, probably via either a di-radical or a vinylcarbene intermediates. This process leads to the formation of a six members ring with a double bond in a terminal chain. After 280 degrees C, the pyrolysis starts to decompose the ester groups into carboxylic acids. FT-IR analysis corroborated the results found by the other techniques. (C) 2013 Published by Elsevier B.V.