The Early Stage of Carbonization of Synthetic Pitches Derived from Aromatic Hydrocarbons Using Trifluoromethanesulfonic Acid as Catalyst

Abstract

The early stage of carbonization of synthetic pitches derived from aromatic hydrocarbons such as naphthalene, anthracene, phenanthrene and 9, 10-dihydroanthracene, with trifluoromethanesulfonic acid as a catalyst were investigated by means of high temperature ESR.Temperature dependence of radical concentration of synthetic pitches observed with in situ ESR showed the following three distinct stages in common; 1st stage, from 100°C to 200°C, where radical concentration increases: 2nd stage, from 200°C to 400°C, in which decreases: and 3rd stage, above 400°C, where again increases. Especially, the change in radical concentration in the 2nd stage is closely related to the form of optical anisotropic texture of derived carbon.The radical concentration of pitches measured at room temperature increased with increasing of average molecular weight, and good correlation was found.