petroleum pitch
A residue from heat treatment and distillation of petroleum fractions. It is solid at room temperature, consists of a complex mixture of numerous predominantly aromatic and alkyl-substituted aromatic @H02889@, and exhibits a broad softening range instead of a defined @M03821@ temperature.
The hydrogen @A00442@ (ratio of aromatic to total hydrogen atoms) varies between 0.3 and 0.6. The aliphatic hydrogen atoms are typically present in @A00228@ substituted on aromatic rings or as naphthenic hydrogen.
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 499 [Terms] [Paper]