High melting temperature synthetic pitches (Synpitches) were created using coal derivatives produced from a solvent extraction technique. Solvent extraction is used to separate hydrocarbons from mineral matter as well as other insolubles. Mild hydrogenation can be used to chemically modify resultant material to produce a true pitch. There are three main techniques which can be used to tailor the softening point of the Synpitch. First, the softening point can be controlled by varying the conditions of hydrogenation, chiefly the temperature, pressure and residence time in a hydrogen overpressure. Second, by selectively distilling light hydrocarbons, the softening point of the remaining pitch can be raised. Third, the Synpitch can be blended with another mutually soluble pitch or hydrocarbon liquid. Through such techniques, spinnable isotropic Synpitches have been created from coal feedstocks. Characteristics of Synpitches include high cross-linking reactivity and high molecular weight, resulting in carbon fibers with excellent mechanical properties. To date, mechanical properties have been achieved which are comparable to the state of the art achievable with conventional coal tar pitch or petroleum pitch.
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