Research On Synthesis Of Pyridine Derived From The Catalytic Ammoniation Of Tetrahydrofurfuryl Alcohol

Pyridine is an important chemical raw material. Pyridine and its derivatives arewidely used in many fields such as dyes, medicinal chemicals and pesticides.Continous synthesis of pyridine using tetrahydrofurfuryl alcohol (THFA) as the rawmaterial was researched in this articile, including the carriers, catalysts and reactionprocess. Meanwhile, the reaction mechanism of synthesizing pyridine from THFA andammonia with metallic oxides as the catalysts was researched.Research on three kinds of commerical carrier commonly used in industry,molecular sieves ZSM-5(Si: Al=25:1), SiO2, and Al2O3, the results showed that thecarrier γ-Al2O3was better than others. The γ-Al2O3was obtained by the calcination ofthe pseudoboehmite. Many simplex catalysts were studied, NiO/γ-Al2O3,Cr2O3/γ-Al2O3also showed good activity besides MoO3/γ-Al2O3, the reaction yieldsof pyridine were30.13%and40.68%, respectively. The reaction products werequantificationally analyzed by using ultraviolet spectroscopy and gaschromatography.In order to increase the yield of pyridine, we put emphasis on the reaserch of thebimetallic oxides MoO3-NiO/γ-Al2O3. The reaction conditions for this catalyst wereoptimized. The reaction yield of pyridine was63%with10%MoO3-10%NiO/γ-Al2O3as the catalyst, when reaction temperature was550℃, the flow rate of THFA was0.15ml/min and n(THFA):n(NH3)=1:10. Whereas, the best yields of pyridine wasonly45.05%used the single metallic oxide MoO3/γ-Al2O3as the catalyst at theoptimized reaction conditions. The catalyst MoO3-NiO/γ-Al2O3can enhance thespecific surface aera and improve the dispersity of the active component. Base on this,the life time of the fresh catalyst MoO3-NiO/γ-Al2O3was investigated in thisdissertation. The yield of pyridine decreased to29.68%after the reaction time of70h.The deactivated catalyst was activated by coke combusting in a furnace. The activityof the deactivated catalyst could not be restored completely and only maintainedabout50h. The results of catalysis characterization revealed that coking was mainlyresponsible for the deactivation of the catalyst, and the catalyst also happened to bepartly sintering; the acid strength of the catalyst active sites was weakened.In addition, to lower the reaction temperature, the process of increasing thereaction pressure was adopted. Under the high reaction pressure, the yield of pyridinestill became better with the reaction temperature higher, but worse than the same temperature under the atmospheric pressure.