Preparation of nitrogen-rich pitches from diazanaphthalenes using AlCl3 Original Research Article

Nitrogen enriched pitches prepared catalytically from diazanaphthalenes (quinoxaline (QX), quinazoline (QZ), and phthalazine (PT)) by the aid of AlCl3 were studied from the viewpoints of the structure and properties of the pitches and their coke due to the different nitrogen locations of starting substrates. The different position of nitrogen in the substrates much influenced the remaining nitrogen content and optical feature of the pitch and the elimination of nitrogen, graphitizability and basicity of the resultant coke. The nitrogen atoms located at a position in QX and QZ almost remained in the resultant pitches during preparation; however, its elimination rate was faster than that at the β position during the carbonization. QX which has two α-nitrogens provided 55 vol.% of anisotropic content in the resultant, yielding the graphitic coke, which showed low basicity. The cokes from QXP and FTP which have one and two β-nitrogens exhibited perfectly isotropic texture and significant basicity measured in water. Nitrogen at the position in the coke is concluded to show a higher basicity by ten times than that at the α position.