Study On The Synthesis Of Pyridine Bases

The application of pyridine bases in the fields of Pharmaceuticals, pesticide, aromatics, rubber, and dyestuff is introduced. The synthetic methods of pyridine bases are reviewed. It is the main way in the industry that pyridine bases are synthesized from carbonyl compounds and ammonia using improved ZSM-5 zeolite as catalyst.ZSM-5 zeolite has high activity for aldehyde-ammonia condensation reaction, with mild reaction conditions, high shape selectivity and little by-product formation. The ZSM-5 zeolite sieve was synthesized using aqueous ammonia and EDA(Ethyl diamine) as template agent. The influence of synthetic reactants ratio and crystallizing time on the synthesis of the zeolite was studied. The results showed that ZSM-5 zeolite sieve could be synthesized using aqueous ammonia and EDA as template agent. The synthetic time increased with the decrease of synthetic temperature. Ni-ZSM-5 and Pb-ZSM-5 zeolites were prepared by the method of iron-exchanged reaction. Through XRD and IR the structures of synthetic ZSM-5 zeolites with aqueous ammonia as template agent were compared with those using EDA as template agent.Aldehyde-ammonia condensation over ZSM-5 zeolite catalyst for synthesis of alkyl-pyridine was studied in this paper. Influence of reaction parameters, such as temperature, reactants ratio(acetaldehyde/formaldehyde and NH3/reactants, molar ratio), and reaction time was discussed and the optimum reaction conditions were found. The activity for aldehyde-ammonia condensation could be enhanced by raising temperature, maintaining at appropriate acetaldehyde/formaldehyde and NH₃/reactants, and prolonging reaction time. High selectivity to pyridine bases and pyridine bases yields of over 70% were obtained under the following condition:480°C, O.lMpa, acetaldehyde/formaldehyde =1/1, NH3/reactants =3 and reaction time 3h.