THE RELATIONSHIP BETWEEN OXIDATION INDUCTION TEMPERATURES AND TIMES FOR PETROLEUM-PRODUCTS

Differential scanning calorimetry (DSC) is an established technique for comparing the oxidation stabilities of substances that contain oxidation inhibitors, e.g. lubricants and polyolefins, for quality control and research purposes. Two types of data can be obtained from DSC: induction times or induction temperatures. A relationship between the two is derived from the Arrhenius equation and, assuming an activation energy of 140 kJ mol-1, this is used to predict induction times from induction temperatures for a variety of materials. The predictions agree with experiment to within +/- 15%. One application of the relationship will be to use an induction temperature to predict the optimal temperature for an isothermal experiment. At a more ambitious level, oxidation induction points could be transformed from the temperature to the time domain.