Deuterium tracer method for investigating the chemistry of coal liquefaction. Final technical progress report, October 1979-September 1981

A novel deuterium tracer method was developed and demonstrated. This method gives a quantitative measure of the hydrogen which is incorporated into specific structural sites during the initial stages of liquefaction. The method was used to begin to investigate the mechanisms of coal hydrogenation. In the current research, hydrogenation experiments were conducted with deuterium gas and/or tetralin-d/sub 12/. In selected experiments, nitrogen or protium gas and/or tetralin-h/sub 12/ was used in conjunction with labeled solvent or gas. Several analytical techniques were used to analyze the soluble hydrogenation products. The principal technique was high-resolution deuteron NMR spectrometry, which is used to determine into which structural positions the deuterium has been incorporated. To assess how much solvent is incorporated into coal under typical liquefaction conditions (425/sup 0/C, 2000 psig), /sup 13/C-labeled tetralin was used so that incorporated solvent could be detected by /sup 13/C NMR spectrometry. The THF-soluble products from this experiment were found to contain three carbon-13 NMR peaks due to solvent incorporation. The GC-MS data agree well with the NMR data with respect to the carbon-13 content of the sample. Only 4 wt % of tetralin and naphthalene were incorporated into the soluble coal products. Experiments to determine the extentmore » of isotopic scrambling in tetralin in the presence and in the absence of coal were conducted with partially deuterated tetralin. Both experiments were conducted at 425/sup 0/C for 1 h in a nitrogen atmosphere. In the experiment in which coal was present, 0.1 g of bituminous coal was used. The results of the two experiments were similar. NMR spectrometry revealed that very little scrambling (approx. 2%) occurred in either experiment.« less