Study On The Synthesis Of Pyridine From Furfuryl Alcohol

Pyridine, an important solvent of organic materials and finechemicals, is widely used in the fields of pesticide, pharmaceutical chemical, tincture, synthetical rubber, and so on. Industrially, it can be produced by catalytic synthesis, or recovering coal tar from the by-product of coking operation. However, the quantity is still far away from the practical demands in China.In this dissertation, the synthetical route of preparing pyridine from furfuryl alcohol was investigated. It is a two-step technology, which includes preparing tetrahydrofurfuryl alcohol by reducing the furfuryl alcohol with hydrogen and preparing pyridine from tetrahydrofurfuryl alcohol.Reaction conditions were determined for synthesizing tetrahydrofurfuryl alcohol by the Ni-catalyzed hydrogenation of furfuryl alcohol in autoclave. The optimal parameters should be 100℃for temperature, 3MPa for pressure, 4g/100mL for the dosage of catalyst and 10h for the reaction time. The purity of tetrahydrofurfuryl alcohol was 99.3%, with a yield higher than 93%.Reaction mechanism of synthesizing pyridine from tetrahydrofurfuryl alcohol and ammonia with Pd/γ-Al₂O₃ as the catalyst was researched with experimental methods. Analysis results showed that the principal product was pyridine and by-products were piperidine, 2-picoline, 3-picoline, 3-ethylpyridine etc. The reaction mechanism deduced from the experimental results is that carbenium ion is firstly formed by the dehydration of tetrahydrofurfuryl alcohol and then pyridine is produced by the ring opening, aminolysis, cyclization and dehydrogenation of carbenium ion.Catalysts like Pd, MoO₃, V₂O₅/γ-Al₂O₃ were prepared and studied for the pyridine synthesis from tetrahydrofurfuryl alcohol and ammonia. Optimal conditions for the reactions catalyzed by the different catalysts were determined. When 10% MoO₃/Al₂O₃ catalyst was used, 95.47% of THFA conversion can be obtained under the condition of 500℃, 0.1mL/min of the tetrahydrofurfuryl alcohol flow, and 1:5 of n(THFA): n(NH3). The multi-component catalyst MoO₃-V₂O₅ can improve the hole structure, enhance the specific surface area and improve reaction performance of the catalyst in contrast with mono-component catalysts.The phenomenon that when La2O3 was loaded on MoO₃-V₂O₅, the selectivity of...