Carbonization of naphthalene and dimethylnaphthalene

A variety of analytical techniques has been utilized to determine the chemical changes which take place during the thermal conversion of the aromatic hydrocarbons naphthalene (N) and dimethylnaphthalene (DMN), to pitch, mesophase, and coke. Aromatic polymerization was shown to play a dominant role at each stage of the coking process. Secondary reactions involving hydrogen transfer and molecular rearrangement were also apparent. Polymerization of (N) occurs largely through the loss of hydrogen while the polymerization of (DMN) involves the elimination of methyl groups. The faster rate of coking for (DMN) compared to (N) is attributed to the activating effect and facile bond cleavage of the methyl group.