关键词: 乙醇脱氢制乙醛, 共沉淀法, 溶液燃烧法, La₂O₂CO₃/ZnO

Abstract:

For the reaction of catalytic dehydrogenation of ethanol to produce acetaldehyde, current catalysts face the challenge of limited selectivity, particularly exhibiting poor performance in the efficient generation of acetaldehyde. Some catalysts are hindered in the dehydrogenation process due to excessive acidity, which urgently needs to be addressed. Therefore, the development of novel catalysts with high?performance surface basicity is crucial.Two composite catalysts, La₂O₂CO₃/ZnO?a and La₂O₂CO₃/ZnO?b, were prepared using the co?precipitation method and the solution combustion method. The performance of the catalysts was evaluated by varying preparation conditions such as precipitation pH, aging time, calcination temperature, and calcination time to determine the optimal synthesis parameters. Advanced characterization techniques, including Scanning Electron Microscopy, Transmission Electron Microscopy, X?ray Diffraction, and CO₂ Temperature?Programmed Desorption, were employed to thoroughly investigate the catalyst's crystal phase, morphology, surface basicity, and their relationship with catalytic performance. The optimal process conditions for ethanol dehydrogenation to acetaldehyde were investigated on the best?performing catalyst. When the precipitation pH was 9.0, the aging time was 12.0 h, the ratio of n_La to n_Zn was 1.0, and the calcination temperature was 600 ℃, the optimal preparation conditions for the solution calcination method were determined as follows: calcination time of 5.0 h, calcination temperature of 550 ℃, and n_La/n_Zn of 1.0. Under the conditions of a volume space velocity of 1.0 h?1, a reaction pressure of 1.0 MPa, and a reaction temperature of 190 ℃, La?O?CO?/ZnO?a achieved the highest acetaldehyde yield of 57.60%.

Key words: Ethanol dehydrogenation to acetaldehyde, Coprecipitation method, Solution combustion method, La₂O₂CO₃/ZnO