Diffuse Reflectance Infrared Fourier Transform (DRIFT) Spectroscopic Studies of Coals: <i>in situ</i> Studies of Acetylation

Abstract

Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy has been utilized to monitor the in situ acetylation of a powdered subbituminous coal at the Oak Ridge Y-12 Plant. The acetylation reaction was carried out by the adsorption of acetic anhydride onto the powdered coal from the gas phase with subsequent heating above 100°C required to initiate the reaction. This technique can be used to gain insight into the hydroxyl (O-H) content of the specific coal sample under study by simultaneous observation of the disappearance of infrared absorptions due to various types of O-H functional groups and of the appearance of absorptions due to carbonyl functional groups resulting from reaction with the anhydride. This entire study can be carried out on a single sample without any intervening sample handling or the introduction of extraneous parameters that could alter the results.