Thermal stability of a fullerene-amine adduct

Abstract

A fullerene-diethylamine adduct has been prepared by an addition reaction at room temperature and is characterized by FTIR, UV-VIS Spectroscopy, X-Ray Diffraction and HPLC techniques. After repeated recrystallisation from hexane the purified adduct has been studied by Thermogravimetry and Differential Scanning Calorimetry. Thermal Analysis and associated characterisation studies indicate that on heating the adduct undergoes an elimination reaction, i.e., the secondary amine which adds on to C₆₀ at room temperature is eliminated between 100 and 650°C. This leads to the formation of the retro product C₆₀ which has been characterized by spectroscopic studies on quenched samples. Kinetics studies indicate that in contrast to the addition reaction which is fast (almost instantaneous) the elimination reaction is sluggish and the process is associated with an activation energy of only 12-13 kJ mol⁻¹. Possible reasons for this unusual kinetic behaviour are suggested.