Research Of Catalytic Synthesis Of Pyridine From Tetrahydrofurfuryl Alcohol

Pyridine is a kind of important chemical intermediate, which is widely used in pesticides, medicines, veterinary drugs, dyes, spices, cosmetics, feed and food additives, meridian tyre industry and other fields. This paper mainly studied the catalyst carriers, active components and cocatalysts of supported catalysts used for the gas-solid phase catalytic synthesis of pyridine from tetrahydrofurfuryl alcohol and ammonia in fixed bed reactor, as well as the influences on catalytic activity, selectivity and life. And we carried out the life experiments with catalyst of the best catalytic performance.We explored the influences on catalyst activity, selectivity and life by different specific surface areas, pore sizes of alumina carriers and different Si/Al ratios of ZSM-5 carriers used for the gas solid phase catalytic synthesis of pyridine from tetrahydrofurfuryl alcohol and ammonia in fixed bed reactor. We selected 5 kinds of commercial ?-Al2O3 carriers of CJ-3, CK-1, YZ-A, HY-1, MLZT, and 4 kinds of different Si/Al ratios ZSM-5 molecular sieves(25H, 38 H, 50 H, 80H), and Al-MCM-41 and mesoporous ?-Al2O3 carriers synthesised in laboratory as the supports of the catalysts compared with the ?-Al2O3 carriers made by pseudo-boehmite. The supported Ni O and Mo O3 catalysts were prepared using impregnation method. Catalyst evaluation results showed that all catalyst carrier activities were good at 550 ?, the conversion rate of tetrahydrofurfuryl alcohol were nearly 100%. The pyridine selectivity of ?-Al2O3 carrier could reach 80%, including the 5 kinds of commercial ?-Al2O3 carriers and the ?-Al2O3 carriers prepared by pseudo-boehmite. But the ?-Al2O3 carriers prepared by pseudo-boehmite showed better life time. The pyridine selectivities of different Si/Al ratios ZSM-5 carriers were about 20% as well as the 3-methyl pyridine. The pyridine selectivities of mesoporous ?-Al2O3 carrier and Al-MCM- 41 were about 70%, but it decreased quickly.We studied the activity and selectivity of the single active component Mo O3 catalyst and Ni O catalyst of different loadings 10%, 15% and 20% at the reaction temperature 500 ? and 550 ?,respectively. The supported catalysts were prepared using impregnation method with the ?-Al2O3 carrier made by pseudo-boehmite. We found that as the temperatures and loads increasing, the pyridine selectivity and yield developed. At 550 ?, the pyridine yield of catalysts loading 20% Mo O3 or 20% Ni O could reach 82%; At 500 ?, the pyridine yields of catalysts at different Mo O3 loads were 60 ~ 70%, and the pyridine yields of catalysts at different Ni O loads were 40 ~ 67%.We studied the influences on catalyst activity, selectivity and life by adding different loads and different kinds of cocatalysts. The Ni O and Mo O3 supported catalysts were prepared using impregnation method with the ?-Al2O3 carrier made by pseudo-boehmite and cocatalysts P2O5, Mg O, B2O3, Zn O, Cu O. We found that P2O5, B2O3, Zn O, Cu O promoted the yield and selectivity of pyridine in the gas solid phase catalytic synthesis of pyridine from tetrahydrofurfuryl alcohol and ammonia in fixed bed reactor, and we carried out continuous lifetime experiment with the best catalytic performance catalysts. The pyridine yield of the Zn O modified catalysts was 88.03%. After the reaction of 50 h, the pyridine yield could stay above 70%.