Kaoru Shibata

E.s.r. study of vanadyl complexes in various carbonaceous materials at high temperature

Abstract E.s.r. spectra of vanadyl complexes in various carbonaceous materials were measured in a range between room temperature and 435 °C. The e.s.r. spectrum of vanadyl complex doped in Taching reduced crude was a slow tumbling pattern at temperatures between 60 °C and 225 °C. By the rapid freezing technique, it became clear that the vanadyl complex in Taching residue was oriented to the magnetic field in its temperature range. Further, activation energies for rotations of vanadyl complexes in those carbonaceous materials were estimated from Arrhenius plots of the correlation times. Those carbonaceous materials were classified into two groups according to values of the activation energies. This classification was consistent with that based on mesophase textures of the cokes made from them.

An e.s.r. study of some coals under rapid passage condition at high temperatures and pressure

Abstract The e.s.r. spectra of Miike and Taiheiyo coals were measured under rapid passage conditions in the temperature range 150–450 °C. A parameter, R , was defined by a ratio of out-of-phase and in-phase spectral amplitudes and the ratios for Miike and Taiheiyo coals were estimated in this temperature range. It was found that the temperature dependence for R was different for the two coals examined, and the reason for the difference was discussed. Further, the ratios for those coals mixed with pyrene were estimated in the temperature range 150–400 °C at atmospheric and 1.1 MPa nitrogen pressure. Based on the temperature dependence of the ratio the coal liquefaction ability of pyrene for those coals was discussed.