In situ study of the hydrogenation of diphenyl ether in the presence of pyrrhotite and hydrogen sulfide

In the present study the results are reported for measurements of the conversion of diphenyl ether to benzene and phenols in the presence of a pyrrhotite catalyst. In situ Moessbauer measurements were performed during the catalytic conversion of diphenyl ether. The presence of Fe/sub 3/O/sub 4/ is detected in the residues after reaction; Fe/sub 1-x/S is also observed. Under high H/sub 2/S partial pressures in the reactor, the conversion increases, and for a 10% H/sub 2/S partial pressure, the Moessbauer spectrum shows the presence of FeS/sub 2/. The amount of Fe/sub 3/O/sub 4/ is practically reduced to zero in this case with Fe/sub 1-x/S dominating the spectrum. All the Moessbauer spectra show the presence of a singlet line after reaction. This spectrum results from the interaction of the iron in the pyrrhotites with the compounds present in the reactor at high temperatures. The conversion of diphenyl ether is negligible in the absence of pyrrhotite. The higher activity observed for conversion in the presence of H/sub 2/S is related to the effect this compound has in controlling the stoichiometry of the pyrrhotites. The activity observed in the iron sulfides toward hydrogenation of diphenyl ether is suggestive of a catalytic role formore » such sulfides in the cleavage of oxygen bonds in direct coal liquefaction. 18 references, 6 figures.« less