Mesophase from a coal tar pitch: a Raman spectroscopy study

Raman spectroscopy has been utilised to detect changes in the structural order accompanying the process of mesophase spherules preparation. A coal tar pitch was selected as the precursor and it was carbonised under the appropriate conditions to produce a discrete amount of anisotropic material present almost completely in the form of spherules. These anisotropic spherules were concentrated by partial removal of the isotropic phase by hot filtration. The analysis by Raman spectroscopy confirmed an increase of the graphene-like orientation from the original coal tar pitch to the final anisotropic concentrate, with the carbonisation semicoke presenting an intermediate behaviour. The results indicate that Raman spectroscopy can be employed to monitor the process of production of mesophase spherules from coal tar pitches by studying the degree of structural order of the resultant product.