Study On The Catalytic Synthesis Of Pyridine And Its Derivatives

As one ofnltrogen-containing compounds, pyridine bases are not only widely used as medicine, insecticide, rubber, aromatics dyestuff. but also as solvent. With the rapid development of chemical industry, the demand of pyridine bases increases quickly. But the way of refining from the coal tar has not satisfied the market needs.Pyridine bases are synthesized through the condensation of formaldehyde, acetaldehyde and ammonia now. By changing original components and the molar ratio, different products can be obtained, the catalyst is ZSM-5 zeolite. ZSM-5 zeolite has high activity for aldehyde-ammonoa condensation reaction, with mild reaction condition, high shape selectivity and little by-product formation.In this work, Pyridine bases are synthesized through aldehyde-ammonoa condensation reaction using ZSM-5 zeolite as catalyst.(1) We modify the ZSM-5 zeolite with specific metals such as lead, zinc, nickel and cadmium. The catalysts were identified by X-ray power diffraction patterns (XRD), Infrared spectra (IR) and Atomic absorption spectrometry (AAS). These catalysts are used for Pyridine bases' synthesis.(2) We choose the Pb-ZSM-5 zeolite as catalyst for the pyridine bases' synthesis.Influence of reaction parameters, such as temperature, reaction ratio and reaction time is discussed and the optimum reaction conditions are found.We obtained better reaction of pyridine bases with formaldehyde, acetaldehyde and ammonia, (1) Using the Pb-ZSM-5 zeolite can improve the total yield of pyridine bases. (2) High selectivity to pyridine bases are obtained under the following condition: reaction temperature=450～470℃, space velocity about 800～1000h^-1, formaldehyde: acetaldehyde: ammonia =1: 2: 4. The regeneration temperature of catalyst is 550℃, after regeneration, the selectivity and activity of the catalyst can be restored mostly.