Chemical Structure and Properties of Heat Treated Coal in the Early State of Carbonization (XVII)

Abstract

Some fundamental examinations were performed on the potassium bromide technique for the i. r. study of coal. The influences of grinding period and moisture content as well as applicability of the Lambert-Beer's law were examined and results were summarized as follows.1. When Yubari coal (86.2%C) was used as a sample, grinding the coal sample with potassium bromide for one hour was found to be sufficient to obtain nearly const-ant optical densities for all absorption bands except at 3450cm-1.2. The absorption band at 3450cm-1 assinged to hydroxyl group was apparently affected by moisture. Its optical density increased with time when a dried potassium bromide pellet was exposed to the air. The specific extinction coefficient, K (l/g·cm) of water was calculated to be 3. 58-3. 85 from the relation between the optical densities at 3450cm-4 and moisture content.3. The Lambert-Beer's law was confirmed to be applicable to the coal samples, and the specific extinction coefficients were caclulated from the linear relationship between coal concentrations and optical densities for almost all absorption bands.