| 저자(한글) |
Peroni, M.,Mancino, G.,Barath, E.,Gutierrez, O.Y.,Lercher, J.A. |
| 초록 |
The use of a series of bulk and supported Ni 2 P and MoP materials in the hydrodeoxygenation of palmitic acid, shows that their catalytic performance can be tuned by the presence of Al 2 O 3 as a support. Al 2 O 3 promotes acid-catalyzed pathways, and influences the phosphide functionality. A series of strategies can be followed to successfully decrease the phosphide particle size, i.e., the use of citric acid (applied to bulk Ni 2 P), and the use of low reduction temperatures (applied to Ni 2 P/Al 2 O 3 ) during the preparation steps. The effects of synthesis parameters and the support on the properties of the phosphides were determined by, e.g., X-ray diffraction, transmission electron microscopy, BET analysis, CO adsorption and NH 3 -TPD. Small particle size of phosphides does not necessarily lead to a large exposed surface of metal phosphide due to residual carbon or to agglomeration of phosphide particles. The specific activities (per gram of material) follow the trend MoP/Al 2 O 3 -TPR (high temperature synthesis) 2 P-CA (citric acid in the synthesis) 2 P/Al 2 O 3 -LT (low temperature synthesis) 2 P/Al 2 O 3 -TPR 2 O 3 -TPR 2 P-CA 2 P/Al 2 O 3 -TPR 2 P/Al 2 O 3 -LT. Thus, the Ni 2 P phase is intrinsically more active than MoP, although the overall activity is determined by the interplay between intrinsic activity and exposed active surface. The conversion of palmitic acid was achieved in a trickle bed flow reactor at varying temperature and residence times. The model reaction follows three different pathway: hydrodeoxygenation (HDO): C 15 H 31 COOH rarr;C 15 H 31 CHO rarr;C 16 H 33 OH rarr;C 16 H 34 ; decarboxylation/decarbonylation (DCO): C 15 H 31 COOH rarr;[C 15 H 31 CHO] rarr;C 15 H 32 ; and esterification: C 15 H 31 COOH+C 16 H 33 OH rarr;C 15 H 31 COOC 16 H 33 . The presence of Al 2 O 3 increases the esterification rates due to relative high acidity, and makes the supported Ni 2 P phase more selective towards CC bond cleavage than bulk Ni 2 P or MoP/Al 2 O 3 -TPR. |
