The mechanism of pyridine hydrogenolysis on molybdenum-containing catalysts : IV. The conversion of piperidine

J. Sonnemans, W.J. Neyens, P. Mars

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The conversion of piperidine was investigated on a CoO-MoO3-Al2O3 catalysts as a function of the temperature, reaction time, initial piperidine partial pressure and the hydrogen pressure. At 60 atm of hydrogen and conversions below 50% piperidine is selectively converted to ammonia and N-pentylpiperidine. This reaction appears to be a two-step process, ring-opening to pentylamine followed by a fast alkyl transfer from pentylamine to piperidine. The piperidine conversion is first order in piperidine as well as in hydrogen, and of -1 order in the total pressure of the nitrogen bases. At higher conversions the rate of formation of pentane and ammonia are influenced by the rate of the (hydro)cracking steps, and also by the equilibrium constants of the alkyl transfer equilibria. The rate of a (hydro)cracking reaction is lower when a ring is present in the nitrogen base. The activation energies of these reactions were 160 kJ mol−1, about 60 kJ mol−1 greater than those of alkyl transfer reactions. At 1 atm of hydrogen the product composition was completely different from that observed at higher pressures of hydrogen. The mechanism of the reactions is briefly discussed.
Original languageUndefined
Pages (from-to)230-241
JournalJournal of catalysis
Issue number2
Publication statusPublished - 1974
Externally publishedYes


  • IR-68197

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