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8095753 
Journal Article 
Effect of reduction temperature on activities of alumina-supported tungsten phosphide in carbazole hydrodenitrogenation 
Li, CQ; Sun, GD; Li, FY; Ji, Y; Zhou, ZJ 
2008 
1 
Ranliao Huaxue Xuebao
ISSN: 0253-2409 
36 
2 
202-207 
English 
A series of WP/Al2O3 catalysts with WO3 loading of 30% were prepared by impregnation and reduced in H2 for 4 h at different temperatures. The catalysts were characterized by XRD, BET, TG and 31P MAS-NMR. Over these catalysts, the hydrodenitrogenation (HDN) of carbazole was performed at 633 K and 3.0 MPa. The results indicated that the active species of WP was accumulated on the support surface at a reduction temperature above 1023 K. Only phosphate was detected at the chemical shift of -2.4 × 10-5 in the catalyst reduced at 923 K. WP species was observed at the chemical shift of 2.55 × 10-4 with low speed of sample rotation in the catalyst reduced at 1073 K, while another peak was also detected with the chemical shift of 6.88 × 10-4 at high speed of sample rotation; this was probably related to a similar structure of -Al-O-W-P owing to the strong interaction of active species with support, which corresponded to the species with the peak at 2θ of 40.44° by XRD. The phosphiding degree of catalyst precursor could be improved by increasing reduction temperature. WP/Al2O3 prepared at 923 K exhibited the highest HDN activity with a carbazole HDN conversion of 79%. Three reaction paths of carbazole HDN were derived, which suggested that hydrodenitrogenation was superior to the direct denitrogenation. 
Carbazole; Hydrodenitrogenation; Phosphide tungsten; Reaction selectivity; Reduction temperature