PYRIDINE SYNTHESIS FROM TETRAHYDROFURFURYL ALCOHOL OVER A PD/GAMMA-AL2O3 CATALYST .2. EFFECT OF SUPPORTS AND PALLADIUM LOADING

Pyridine synthesis from tetrahydrofurfuryl alcohol and ammonia was carried out over palladium catalysts supported on SiO2, La2O3, gamma-Al2O3, SiO2-Al2O3, TiO2, and HF-Al2O3. Of the supports examined, gamma-Al2O3 exhibited the highest yield of pyridine. Strong acid supports like SiO2-Al2O3 and HF-Al2O3 suppressed the catalytic activity, whereas nonacidic supports such as SiO2 and La2O3 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 angstrom. 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.