Benzene → Quinoline

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Reaction Steps

As the aromatic, low-boiling solvent, use may be made of any solvents having a boiling point of not more than 250° C., which includes benzene, toluene, xylene, pyridine, raw naphthalene oil, gas light oil, tar light oil and a mixture thereof. The reason why the boiling point of the solvent is limited to not more than 250° C. is based on the facts that such a solvent is easy to be recovered from the solution after the removal of the insoluble matter and that high molecular weight components corresponding to high heat-reactive pyridine insoluble matter in the pitch can efficiently be removed because this solvent exhibits an adequate dissolving power to the pitch. That is, the aromatic solvent having a boiling point of more than 250° C. is generally high in the dissolving power, so that if the pitch is dissolved in the latter solvent such as anthracene oil, only the quinoline insoluble matter such as free carbon, inorganic matter and the like naturally contained in the pitch is substantially separated and removed and consequently the obtained pitch still contains high molecular weight components corresponding to the pyridine insoluble matter. When such a pitch is subjected to a heat treatment, the high molecular weight components having a rich heat reactivity are polycondensed to form mesophase as a secondary quinoline insoluble matter, so that it is difficult to produce a precursor pitch of homogeneous phase suitable for the production of carbon fibers. For this reason, the use of the aromatic solvent having a boiling point of more than 250° C. such as anthracene oil, quinoline and derivatives thereof is not favorable to the invention.

Provenance & Evidence