Quantitative Analysis of Coal Tar-Based Pitch by Solid-State ~(13)C-NMR

摘要

Novel analytical method using solid-state ~(13)C-NMR to analyze the aromaticity and quaternary carbon content of coal tar-based pitch was developed and presented. The analytical conditions including magic angle spinning (MAS), high power decoupling (HPD), single pulse excitation (SPE), cross polarization MAS (CP MAS) are optimized for the pitch characterizations. Coal tar-based pitch samples were prepared with different composition, treated condition, softening point and analyzed. Pitches with higher softening point or heavier fraction (extracts with stronger solvent) were found to have higher aromaticity as well as rich quaternary carbon content. Further qualitative and quantitative analysis suggested that the treatment conditions of carbonaceous precursors influenced the aromaticity and quaternary carbon content of prepared pitch.