Research And Application Of Fixed Bed Catalytic Synthesis Of Pyridine And Its Derivatives

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,medicine and feedstuff industry, the needs of the pyridine bases expanded quickly.Now, there are two main sources about pyridine bases: one is distilling from coal tar, the other is chemical synthesis. Because of low yield, inferior quality and few variety, the distilling can't satisfy the demand. So the chemical synthesis is the main. But as far as the independent property for synthetic technology and the manufacture equipment in our country are concerned,it's a blank in this area. So it is important to study our own technology to produce pyridine bases.This way mainly is completed through the condensation of formaldehyde, acetaldehyde and ammonia in the latest producing devices. Different products and different distributions can be obtained by changing original components and the ratio(mol). The common catalyst is ZSM-5 zeolite.Futher research has been experimented on catalysts and the technical conditions of synthesis which used formaldehyde, acetaldehyde and ammonia as raw material since 2005. Based on the study, the main contents of this task are: (1)choose the noble metal Pd-ZSM-5 as the catalyst for the pyridine bases'synthesis, carry out the research of technical conditions of synthesis which formaldehyde, acetaldehyde and ammonia are used as the raw material and the better synthesis conditions are selected. And characterize the catalyst. (2) research the separation, and the better separation mode is selected.We obtained the results as the following: (1) the better reaction condition of pyridine bases with formaldehyde,acetaldehyde and ammonia: reaction temperature:400℃～440℃, formaldehyde : acetaldehyde : ammonia : water = 1:1:4:14(mol), space velocity: about 1200 h-. The totoal yield of pyridine bases is over 80%. The life of Pd-ZSM-5 is long, it is a excellent catalyst for synthesis of pyridine bases. (2)the better separation mode of adopting saturated KF liquor is selected. And the pyridine bases recovery ratio is exceeded 97%, the dehydration ratio is exceeded 88.12%.