Hydrogenation of Coal Model Compounds Using Chromium Oxide Catalysts

Abstract

The activity of chromium oxide catalysts which promoted the hydrogenation of Yubari coal, were estimated using naphthalenes and 1-naphthol as coal model compounds. Naphthalene was mainly hydrogenated to tetralin, and its yield and selectivity reached approximately 80% and 90%, respectively. Moreover, the activity of chromium oxide catalyst was compared with those of some commercial hydrogenation catalysts. The characteristic of this catalyst was similar to that of Cu-Cr catalyst. From the standpoint of selective formation of tetralin, this catalyst was the best of these commercial catalysts. 1-Methylnaphthalene was mainly hydrogenated to 1- or 5-methyltetralin along with naphthalene and tetralin. In this reaction, two pathways were observed: dealkylation and hydrogenation. Furthermore, the amount of tetralin was fairly large with increasing reaction time. 1-Naphthol was mainly reductive
Deoxygenation to naphthalene and hydrogenated to tetralin. The catalyst activity, however, was remarkably depressed under the influence of water formed by the hydrocracking of 1-naphthol. The XRD analysis showed that the chromium oxide catalysts contained too much Cr₂O₃. Therefore, it was considered that the activity of chromium oxide catalyst was caused by a small amount of undetermined chromium oxides present in chromium oxide catalyst.