Some quantitative infra-red absorption studies of coals, pyrolysed coals, and their acetyl derivatives

Abstract

Quantitative studies have been made of the changes in the infra-red spectra of coals and chars that follow their acetylation. Those features in the spectra of the acetylated materials that are characteristic of the acetate groups were found to vary quantitatively with the chemically determined acetyl contents. Changes occurring in the hydroxyl absorption (at 3380 cm-1) as a result of pyrolysis and acetylation tend to confirm that the 5 to 7 per cent. of oxygen which is not detected in the functional group analysis of Victorian brown coals is predominantly in the form of hydroxyl groups which resist acetylation and which appear to be stable on heating to about 450 �C.