Study On Preparation Of Sec-butyl Acetate Hydrogenation To Sec-butyl Alcohol Catalyst And Its Performance

Sec-butanol is an important chemical that can be used in the production of methyl ethyl ketone,lubricants,dyes,and perfumes.Recent studies have shown that sec-butanol can be used in place of MTBE and mixed with gasoline,it is an ideal gasoline blending component.However,mature sec-butanol production technology are mainly indirect hydration method and direct hydration method,these two production processes have obvious defects:in indirect hydration method,the use of sulfuric acid causes serious equipment corrosion;in direct hydration method,the conversion rate of raw materials is very low,and the energy consumption is very high.Therefore,it is of great significance to develop new methods for preparing secondary butanol.In this paper,the effects of preparation methods and precursors on the catalytic performance of CuO/ZnO/Al₂O₃ catalysts are studied firstly.The preparation methods of the catalysts mainly studied the impregnation method,wet mixing method and dry mixing method.The precursors mainly studied nitrate and Basic salt;Secondly,the effect of preparation conditions on the catalytic performance of the catalyst during preparation of the catalyst is studied;Thirdly,the influence of reaction conditions on the catalytic performance of the catalyst is studied also;Finally,the reason for the deactivation of the catalyst is studied.By studying the catalyst preparation method and precursors,it can be found that the preparation method and the precursor have a great influence on the structure and activity of the catalyst.The hydrogenation activity of the CuO/ZnO/Al₂O₃ catalyst is not completely proportional to the specific surface area,the activity is also closely related to CuO particle size and the synergistic effect of Cu-ZnO.The catalyst prepared by the basic salt and wet mixing method has the best reaction performance because of its larger specific surface area,smaller CuO particle size,and stronger Cu-ZnO acting force.In the subsequent experiments in this paper,the basic salt and wet mixing method will be used as the preparation method of the CuO/ZnO/Al₂O₃ catalysts.By studying the preparation conditions,it can be found that when the catalysts calcined at 350°C,w（Cu）=30%,m（Cu:Zn:Al）=4:2:1 and w（Fe）=6%,the catalyst has the best hydrogenation activity respectively.At this time,the specific surface area of the catalyst is larger,and the active component CuO particle size is smaller,the interaction force between Cu-ZnO is stronger.Through the examination of the four reaction conditions:T,P,n and LHSV,the experiment is designed according to the control variable method,when the catalyst reacted at T=225°C,P=4.5MPa,n=15:1,and LHSV=0.60 h^-1,the hydrogen performance is best respectively,and the catalyst reaction performance is tested under optimal reaction conditions,the X_SBAC can up to 96.98%,the S_SBA can up to 98.17%,and the S_EA can up to77.35%.The reasons for the deactivation of CuO/ZnO/Al₂O₃ catalysts are systematically analyzed by means of BET,NH₃-TPD,TG-DTA,XRD,and SEM.It can be found that the presence of weak acid sites and moderately strong acid sites in the Al₂O₃ support,resulting in the formation of carbon deposits and the catalyst deactivated;In addition,due to the fact that the interaction between the Cu-ZnO catalysts is not very strong,the distribution of the active components is not very uniform,and the agglomeration is prone to occur,so that the catalyst is easily heat-sintered,thereby reducing the activity of the catalyst.