摘要: This paper analyzes the coal to char stages of char formation of six coals of different ranks by using Fourier transform infrared coupled with attenuated total reflectance (ATR-FTIR). The chars were obtained by coal pyrolysis carried out at temperature range of 450 ~700. The data obtained shows the pragmatic disappearance of the aliphatic hydrogen content with increasing char formation temperature. Numerical evaluation of the spectra enabled the determination of aromaticity, f_a. The aromaticity was found to be between 0. 66 ~0. 79 for lignite, 0. 75 ~0. 90 for sub-bituminous, 0. 84 ~1. 00 for low volatile bituminous, 0. 83 ~ 1. 00 for high volatile bituminous, 0. 94 ~1. 00 for semi-anthracite, and 0. 97 ~1. 00 for anthracite respectively. With increasing rank of coal samples, spectra exhibit rising aromaticity and enhanced condensation of aromatic rings, whereas the aliphatic chain lengths decrease.