Carbonization of Aromatic Hydrocarbons. II. Carbonization of Modified Pyrene in the Presence of Aluminum Chloride

Abstract
The carbonization of four hydrogenated and two methylated pyrene derivatives in the presence of aluminum chloride was investigated to elucidate the effects of the slight structural perturbation on the carbonization properties of pyrene. Hexahydropyrene was found to give coke having a needle-like structure via similar carbonization steps as naphthalene followed. In contrast, dihydropyrene formed coke of a mosaic structure for the most part. Although 1-methylpyrene produced coke with a needle-like structure, in part, reductively methylated pyrene was converted to a mosaic structure as was pyrene. In the case of needle-coke formation, the carbonization process of hydrogenated and methylated pyrene followed the steps of appearance, growth and coalescence of anisotropic spheres where the reaction started at a lower temperature and proceeded more moderately compared with the case of pyrene. It is thus indicated that a partially lowered aromaticity of pyrene may favor its carbonization into needle coke.