Determination of aromatic and aliphatic CH groups in coal by FT-i.r.: 2. Studies of coals and vitrinite concentrates

Various methodologies used to determine the aliphatic and aromatic CH contents of coal are discussed. The problems associated with equation i.r. band intensities to elemental hydrogen are examined in some depth. The equations used to determine absorption coefficients (defined here in terms of ‘conversion factors’) are classically ill-conditioned, so that a range of solutions are obtained. However, for bituminous coals these encompass and are close to the values obtained by calibrating with the results of proton n.m.r. studies of coal extracts. Values of aromatic to aliphitic hydrogen ratios are reported and compared to those published previously.