The formation of isoprene and DL-limonene during waste tyre pyrolysis was investigated in terms of the effect of the heating rate (up to 100 degrees C/min). Ion current signals were used to track during pyrolysis the evolution of the predominant ions of isoprene (isoprene 67) and DL-limonene (limonene 93), by using a thermogravimetric analyser coupled with mass spectrometry (TGA/MS). The combined model-free and model-based kinetics were used to estimate the activation energy (E-a) for isoprene and DL-limonene formation at 131 and 115 kJ/mole, respectively, based on the Kissinger method. Reaction order (n) values were estimated at 1.2 and 1.1 for isoprene and DL-limonene, respectively. Better model fit (R-2 = 0.998) of the experimental data to the Arrhenius equation for isoprene and DL-limonene, respectively, was observed when the Kissinger method was used compare to Friedman method. Although the E-a values for isoprene and DL-limonene were not significantly different, the combined three kinetic parameters (E-a, pre-exponential constant (A), and n) may be significantly different. Therefore, for DL-limonene formation selectivity over isoprene, the differences in the three kinetic parameters values for each compound model and heating rate on the reaction progress was significant. The reaction progress at peak isoprene and DL-limonene formation rate increased from 0.42 to 0.45 and more significantly from 0.35 to 0.44, respectively as the heating rate was increased from 15 to 100 degrees C, confirming that the preferred strategy to maximise DL-limonene production is rapid heating to the moderate final pyrolysis temperature. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.