Radicals from the Pyrolysis of Tobacco

Abstract

The fractional pyrolysis of Bright tobacco was studied in an inert nitrogen environment at atmospheric pressure over a temperature range of 200−700 °C, using a continuous-flow reactor system. The effect of pyrolysis conditions on the generation of free radicals and their distribution among total particulate matter (TPM), char residue, and the gas phase was characterized using electron paramagnetic resonance (EPR) and EPR spin-trapping techniques. It was found that the fractional pyrolysis of tobacco led to the generation of free radicals with g-factors of 2.0035−2.0040. They were formed during pyrolysis at temperatures of >380 °C and were present in both char and TPM. The concentration of these radicals in TPM varied from 0 spins/g at 240 °C to 11 × 1016 spins/g of TPM at 620 °C. The concentration of these radicals in the char residue increased as the pyrolysis temperature increased; a maximum concentration of 1.2 × 1019 spins/g of char at 480 °C was obtained, and then the value declined. The g-values of ...