The Synthesis Of Pyridines By Catalytic Amination Of Glycerol Over HZSM-5/11 Intergrowth Zeolite

Pyridines are widely used in the fields of medicines,pesticides,rubbers and dyestuffs.With the rapid development of chemical and pharmaceutical industries,the demand for pyridines is increasing quickly.Nowadays,there are mainly two methods for producing pyridines:one is distilling from coal tar,the other is catalytic synthesis from aldehydes and ammonia.Up to now,more and more attention has been paid to the replacement of fossil energy by renewable biomass energy along with the growth of energy demand and the improvement of environmental protection consciousness.On the basis of literature researches,we are aim to develop an efficient catalyst for the synthesis of pyridines from glycerol-ammonia,which is a new way to synthesize pyridines.A composite co-crystalline zeolite HZSM-5/11?78?was prepared and subsequently used to catalyze the conversion of glycerol with ammonia to pyridines including pyridine,2-methylpyridine and 3-methylpyridine in this thesis.The HZSM-5/11?78?showed good performances compared to zeolites with similar Si/Al ratio such as HZSM-5?80?,HZSM-11?80?and the physical mixtures of HZSM-5?80?and HZSM-11?80?.N₂adsorption-desorption and pyridine adsorption IR experiments revealed that the good performance of HZSM-5/11?78?probably resulted from its higher surface areas and the co-existence of Lewis and Br?nsted sites in an appropriate ratio.In addition,the factors affecting the catalytic performance of HZSM-5/11?78?were systematically investigated.Meanwhile,the optimal conditions for producing pyridines from glycerol with ammonia over this catalyst were determined,which were reaction temperature of 520°C,0.1 Mpa pressure,the molar ratio of ammonia to glycerol of 12:1,and GHSV of 300 h^-1,respectively.Under the optimal conditions,the total carbon yield of pyridines could reach up to 40.8%,which is 14.3%higher than that of using HZSM-5?80?as the catalyst.