Study Of The Preparation Of Catalyst And The Technology Of The Oxidative Demethylation Of Picoline

Pyridine is an important organic synthesis intermediate and fine chemical raw material,which is widely used and has a large demand.However,a large number of picoline by-products,which has a limited use,were produced in the current production of pyridine.Developing the technology of picoline demethylation to synthesis pyridine not only improves the utilization of picoline value,but also regulates the production structure of pyridine bases.Therefore,for the technology of oxidative demethylation of 3-picoline,in this paper,two catalysts,V-Ag-Fe/TiO₂and V-Ag-Ce/TiO₂were prepared by impregnation method.Combined with the characterization of catalytic structure and evaluation of catalytic performance,the effects of preparation conditions on the oxidative demethylation performance of picoline were investigated.Also,the preparation conditions of catalyst and the3-picoline oxidative demethylation process were optimized.Research results show that the catalytic activity of V-Ag/TiO₂on oxidative demethylation of 3-picoline can be improved by the modification of Fe and Ce,and the catalytic activity of V-Ag-Fe/TiO₂is much higher than that of V-Ag-Ce/TiO₂.Then,the calcination temperature of catalyst,V₂O₅loading,Ag and modified component doping are the main factors affecting the catalytic performance.The optimum conditions for the preparation of V-Ag-Fe/TiO₂were as follows:calcination temperature 450℃,calcination time 4 h,loading of active components V₂O₅and Ag were 15%and 1.5%respectively,molar ratio of Fe:V was 1:2.The optimum conditions for the preparation of V-Ag-Ce/TiO₂were as follows:calcination temperature 450℃,calcination time 4 h,the loading of active components V₂O₅and Ag were 15%and 2.0%respectively,and the molar ratio of Ce:V was 1:3.The reaction temperature and air flow were the main factors affecting the demethylation of3-picoline.When V-Ag-Fe/TiO₂and V-Ag-Ce/TiO₂were used as catalyst,the optimum reaction temperatures were 300℃and 350℃respectively.When increased the flow of air,3-picoline conversion and pyridine yield increased significantly,but pyridine selectivity change was not obvious.The yield and selectivity of pyridine respectively reached 62.97%and 78.75%under the optimized demethylation conditions.Also,the catalyst has good stability and is not easy to be inactivated.These catalysts have good development and application value.