TEMPERATURE DEPENDENCE OF ¹H NMR ABSORPTION IN COAL AND PITCH.

Many kinds of reactions such as pyrolysis, depolymerization, condensation occur simultaneously in complicated way when coal and tar pitch are heated over temperature range from 350 degree C to 500 degree C. In order to understand the processes of coal liquefaction and coal carbonization, it is important to clarify the characteristics of reaction behaviors for coal and tar pitch over the temperature range. This paper deals with observation of resolved NMR spectra corresponding to aromatic and aliphatic protons at high temperatures in a tar pitch. Experimental results are presented which show that the maerials which give spherical mesophase on heating show a narrowing of the NMR with increasing temperature which corresponds to so-called softening and plastic stages. Moreover, the degree of motional narrowing of the proton NMR spectra reflects the degree of fluidity at the plastic stage. The temperature dependence of hydrogen aromaticity would be monitored directly by using the NMR high temperature technique. Chemical reactions such as pyrolysis, depolymerization, condensation could be clarified. Moreover, application of the technique seems to be promising in the mechanism of coal liquefaction as well as that of mesophase formation.