Studies On The Selective Oxidation Of Acrolein To Acrylic Acid Over The Mo-V-based Complex Metal Oxide Catalysts

Acrylic acid is an important chemical raw material,it can be directly generated polymers,or generated acrylate ester,then it aggregates again,they have a very important prospects for industrial applications.In the process of the selective oxidation of acrolein to acrylic acid,it generally uses the Mo-V mixed metal oxides catalysts and can continuous production in a fixed-bed reactor,so it has important significant and broad prospects and provides anew route for the preparation of acrylic acid.This thesis mainly researches the series of the Mo-V and the load type catalysts.The preparation of the catalysts,the best atomic ratio and the influence of the reaction conditions were investigated in a fixed-bed reactor.The research content and experimental result were listed as follow:?1?In the research of the Mo-V mixed metal oxides catalysts in the selective oxidation of acrolein to acrylic acid,the acrolein aqueous solution was the best suitable material;at the same time,the preparation methods of catalysts was investigated,the best preparation was the solution evaporation method;Moreover,the Mo-V-W-Cu-Ca was the best catalytic activity through screening the catalysts;The optimal ratio of atoms was 12:3:1.2:1.5:0.24;The optimal condition for the preparation of catalyst was calcined at 400 ? in air atmosphere and maintain 6 h;The experimental results showed that the highest acrolein conversion of 98.15%,the acrylic acid selectivity of 66.05%and the acrylic acid yield of 64.83%were obtained on Mo-V-W-Cu-Ca under the conditions of reaction temperature = 280 ?,the weight hourly space velocity?WHSV?= 0.3 h-1,the oxygen aldehyde ratio = 1.62.In addition,the structure of the Mo-V catalysts were investigated by XRD,N₂-physical adsorption,SEM,FT-IR,UV-Vis.The result showed that the V_0.13Mo_0.87O_2.93 and V_0.12Mo_0.88O_2.94 phases were the largest influence factors on the result of the reaction.?2?In the research of Mo-V-W-Cu-Ca/support catalysts in the selective oxidation of acrolein to acrylic acid,it was used different carriers,the loading methods?the amount of metal loading and the catalytic performance were investigated.The results showed that the highest acrolein conversion of 99.21%,the acrylic acid selectivity of 82.48%and the acrylic acid yield of 81.82%were obtained on the 70 wt%Mo-V-W-Cu-Ca/?-Al₂O₃ throuhg step impregnation method for loading between the active component and carrier.In addition,the structure and the stability of the Mo-V-W-Cu-Ca/?a-Al₂O₃ supported catalysts and the regeneration condition were investigated by XRD,N₂-physical adsorption,SEM,FT-IR,UV-Vis,TG.It was further evidenced that the calcination temperature of the catalysts could only remain at 400 ?.?3?In the research of Mo-V-W-Cu-Ca-xSi-?-Al₂O₃ in the selective oxidation of acrolein to acrylic acid,it mainly investigated the preparation methods of the mesoporous ?-Al₂O₃,the modified of the mesoporous ?-Al₂O₃ and the best catalytic performance of the load catalyst.It turned out that the preparation of the mesoporous?-Al₂O₃ was used the aluminium source of aluminium isopropoxide,the surfactant of the F127,adding nitration,stirring 6 h at room temperature.To improve the water thermal stability of the mesoporous ?-Al₂O₃,it was modified by Si.The highest acrolein conversion of 98.46%,the acrylic acid selectivity of 86.57%and the acrylic acid yield of 85.24%were obtained on the Mo-V-W-Cu-Ca-4.5Si-?-Al₂O3.In addition,the structure of the ?-Al₂O₃ was investigated by XRD,N₂-physical adsorption,FT-IR.The results showed that it was formed the required mesoporous material.