Study On The Synthesis Of Pyridine Bases And Catalysts

Pyridine bases are widely used as intermediates in the formation of medicine, insecticide, rubber and dyestuff besides as solvents. With the rapid development of chemical industry , the demand for the pyridine bases increases quickly. But the way of refining from the coal tar hasn't satisfied the market needs, therefore replaced by the synthesis means. Several producing devices are imported from foreign countries, so it is important to study the pyridine bases' synthesis means, including the catalysts applied in the synthesis means.This way mainly is completed through the condensation of formaldehyde, acetaldehyde and ammonia in the latest producing device. By changing original components and the mol ratio, different products and different distributions can be obtained, the catalyst is ZSM-5 zeolite.The main contents of this task are:(1)choose the H-ZSM-5 zeolite as better catalyst for the pyridine bases' synthesis , carry out the research of technical conditions of synthesis which formaldehyde, acetaldehyde and ammonia are used and better synthesis conditions are selected. Besides these procedures, the addition of propionaldehyde as the third aldehyde for improving of the 3-picoline was studied.(2)carry out the ion-exchange of the H-ZSM-5 zeolite for the synthesis of pyridine bases;(3) research the reaction of pyridine methylation with H-ZSM-5 zeolite and the spinel through co-precipitation .We obtained better reaction condition of pyridine bases with formaldehyde, acetaldehyde and ammonia, i.e. space velocity about 1000h-1, formaldehyde : acetaldehyde =1 : 1, organic compound : ammonia=1 : 4, reaction temperature =450℃-475℃.The addition of the propionaldehyde can improve the yield of 3-picoline rather than effect the total yield of pyridine bases. By using the ion-exchange zeolite Zn-ZSM-5 can improve the total yield of pyridine bases by 10% than ordinary H-ZSM-5 zeolite; The methylation reaction with the spinel and the H-ZSM-5 zeolite indicates that catalysts have some effects on the pyridine's methylation, but the yield is too low (<= 5%) ,so it is necessary to further the study.