Pyridine synthesis from tetrahydrofurfuryl alcohol over a Pd/γ-Al 2O 3 catalyst : II. Effect of supports and palladium loading

Abstract

Pyridine synthesis from tetrahydrofurfuryl alcohol and ammonia was carried out over palladium catalysts supported on SiO 2, La 2O 3, γ-Al 2O 3, SiO 2-Al 2O 3, TiO 2, and HF-Al 2O 3. Of the supports examined, γ-Al 2O 3 exhibited the highest yield of pyridine. Strong acid supports like SiO 2-Al 2O 3 and HF-Al 2O 3 suppressed the catalytic activity, whereas nonacidic supports such as SiO 2 and La 2O 3 induced the decomposition of tetrahydrofurfuryl alcohol. The reaction was significantly affected by the acidity of the supports. Selectivity for pyridine was greatly affected by the palladium loading. The optimum particle size of palladium for selective pyridine synthesis was found to be 30–40 Å. The effect of the support and the palladium particle size on pyridine synthesis was well interpreted by the metal-support interaction caused by charge transfer.