Deuterium tracer method for investigating the chemistry of coal liquefaction. Annual technical progress report, July 1976--June 1977

Abstract

A novel deuterium tracer method was established and demonstrated. This method permits the determination of the sites of hydrogen incorporation in the coal structure during hydrogenation. Specifically, the method consists of conducting pairs of hydrogenation experiments, one with protium (the common isotope of hydrogen) and the other with deuterium, under identical experimental conditions. For each pair of experiments, the hydrogenated products are analyzed by proton nuclear magnetic resonance (NMR) spectrometry. All products were also analyzed by carbon-13 NMR spectrometry to obtain insight into the structural characteristics of the carbon skeletons of the hydrogenation products. Aside from the advantage of direct observation of the carbon skeleton, carbon-13 NMR affords the direct observation of carbon-containing functional groups that have no attached protons (e.g., carbonyls). Preliminary experiments were conducted to establish effective operating conditions for the planned hydrogenation experiments. Then, in order to obtain baseline data, the first two pairs of protium/deuterium hydrogenation experiments were conducted with coal and hydrogen. The results of the experiments described, the impact of the results on elucidating the mechanism(s) of coal hydrogenation, and an evaluation of the deuterium tracer method are presented. Also, a comparison between the subtractive technique, using proton NMR spectrometry, and the direct proceduremore » of determining deuterium incorporation using deuteron NMR spectrometry is presented.« less