Infra-red spectra sf Japanese coal.
-The abshption bands at 3 030, 2 920 and I600 cm-'
S. FUJII, Y. OSAWA AND H. SUGIMURA Infra-red spectra of twelve Japanese coals, from lignite to anthracite, were measured as accurately as possible using potassium bromide discs. The absorption band at 3030 cm-l (aromatic CH hydrogen) appears in the coal with 81.1% carbon (d.a.f.) and becomes clearer as coal rank increases.
With the exception of a few coals, the absorption intensity of 2920 cm-l (aliphatic CH hydrogen) increases gradually with rank until 86.2 % carbon, but decreases sharply beyond this point. The increase in intensity at 1600 cm-l, in parallel with oxygen content suggests that oxygen-containing structures, as well as the C=C aromatic structure, cause this absorption.
The marked intensity of the aliphatic CH hydrogen absorption, especially at 2920 cm-l, is found to be the characteristic feature in the infra-red spectra of Japanese coals in comparison with others.
* These vitrains were prepared and distributed by the Coal Mining Research Centre of Japan to the members of the Coal Research Group in Japan.