Hydrogenation of dibenzyltoluene and the catalytic performance of Pt/Al₂O₃ with various Pt loadings for hydrogen production from perhydro-dibenzyltoluene

The characteristics of the hydrogenation of dibenzyltoluene and dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) are investigated. The hydrogenation experiments are conducted using Raney-Ni. It is found that 170°C and 7 MPa is the optimal reaction condition at which the hydrogen capacity of 6.2 wt% is achieved in 30 hours. The optimal temperature for the dehydrogenation of H18-DBT is found to be 290°C. Moreover, the dehydrogenation of H18-DBT is carried out over Pt/Al₂O₃ catalysts with different Pt metal loadings (1% ~ 5%). The results elucidate that 5% Pt/Al₂O₃ is the most active catalyst yielding 90.2% of the stored hydrogen in 7 hours. The catalytic activity of the catalysts is in the order 5% > 4% > 3% > 2% > 1% Pt/Al₂O₃. The increment in catalyst dosage increases the reaction rate and hydrogen yield%. Lastly, the cyclic experiments are conducted and DBT is found to be quite stable in all three cycles. HIGHLIGHTS: The complete hydrogenation (6.2 wt%) of dibenzyltoluene is achieved at 170°C and 5 ~ 7 MPa. The dehydrogenation of perhydro-dibenzyltoluene is conducted over 1 ~ 5% Pt/Al₂O₃. The 90.2% of stored hydrogen is produced over the optimal catalyst, 5% Pt/Al₂O₃. The hydrogen production in all the three cycles is almost similar which makes dibenzyltoluene a stable liquid organic hydrogen carrier.