Abstract: The kinetics of the thermal decomposition of the kaolin: dimethylsulfoxide (kaolin: DMSO) and the kaolin: N-methylformamide (kaolin: NMF) intercalates have been reexamined. Two different sample sizes (2 mg and 8 mg) and grain-size distributions (<45 µm and 45–63 µm) were investigated using isothermal and dynamic gravimetry in the temperature range 100°–200°C. All sample configurations for the kaolin: DMSO intercalate (2 mg, <45 µm; 2 mg, 45–63 µm; 8 rag, <45 µm; 8 mg, 45–63 µm) followed the rate law -ln(1 - α) = kt to a value for α, the reaction fraction complete, of .6, yielding activation energies and standard deviations at the 99% confidence level of 85.5 ± 3.79 and 71.75 ± 8.75 kJ/mole for the isothermal and dynamic runs, respectively. The kaolin: NMF intercalate (2 mg, <45 µm) also followed the same rate law for α < .8, with activation energies and standard deviations at the 99% confidence level of 89 ± 5.05 and 79.25 ± 6.47 kJ/mole for the isothermal and dynamic studies, respectively. In solution the rate law -ln(1 - α) = kt is known as first-order kinetics, but here it appears to represent the non-instantaneous nucleation of uniformly sized particles, followed by the inward movement of a reaction interface.