Catalytic condensation of isoquinoline into pitch in higher yield in the presence of nitro solvents

Yield, structure, and properties of nitrogen containing pitches prepared catalytically from isoquinoline by the use of AlCl₃-co-catalyst(nitroethane. nitobenzene) system were studied to increase the yield and nitrogen content of such pitches as a precursor for speciality carbon. Nitroethane(NE) and nitrobenzene(NB) as the co-catalyst increased the yield of the pitch up to 52% compared to 11% without the co-catalyst. The yield, insoluble content, softening point, molecular weight and nitrogen content increased with the amount of co-catalyst. Behaviour of nitrogen atoms and the properties of pitches thus prepared during the carbonization were also investigated. Coke provided from isoquinoline pitches prepared with NB exhibited a higher yield, more complete optical isotropy and retained more nitrogen than that prepared with NE. The coke produced at 600 C from the former pitch exhibited a high basicity of 0.22 mmol g due to a higher nitrogen content (5.2 matom g) than that from the pitch prepared without the co-catalyst. The roles of the nitro compounds are discussed in terms of the oligomeric constitution of the pitch and the relation ol its structure to its carbonization properties.