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Denitrogenation of piperidine on alumina, silica, and silica-aluminas: The effect of surface acidity

Journal Article · · Journal of Catalysis; (United States)

Alumina, silica, and three silica-aluminas having 10, 50 and 90 wt% SiO{sub 2} were prepared and characterized for the total acidity, acid strength distribution, and Broensted/Lewis acidity. The characterization involved the techniques of ammonia chemisorption, temperature-programmed desorption (TPD), and FT-IR spectroscopy. The effect of surface acidity on denitrogenation selectivity was studied by means of the reactions of piperidine in a continuous-flow fixed-bed reactor operated at atmospheric pressure and 320-340 C. The overall piperidine conversion to various products increases with the total acidity of the catalysts. However, the denitrogenation selectivity depends only on the concentration of Broensted acid sites, demonstrating the participation of those sites in the deamination mechanism and hence showing evidence for the Hofmann elimination pathway. The other important reactions of piperidine were alkylation, condensation, disproportionation, and dehydrogenation, to yield alkylpiperidiens, 2,3,4,5-tetrahydropyridine, pyridine, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydro-3-methylquinoline, 5,6,7,8-tetrahydroquinoline, and decahydroquinoline.

DOE Contract Number:
FG22-89PC89771
OSTI ID:
7106523
Journal Information:
Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 137:2; ISSN 0021-9517; ISSN JCTLA
Country of Publication:
United States
Language:
English