Effects of reaction conditions on one‐step synthesis of methylal via methanol oxidation catalyzed by Mo:Fe(2)/HZSM‐5 catalyst. (26th January 2021)

• Record Type: Journal Article
• Authors: Tian, Yuanyu; Yuan, Meng; Li, Shen; Tang, Ruiyuan; Zong, Peijie; Qiao, Yingyun
• Is Part Of: International journal of energy research. Volume 45:Number 5(2021)
• Page Start: 7487
• Page End: 7500
• Publication Date: 2021-01-26
• Subjects: methanol -- methylal -- optimum process conditions -- reaction conditions; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.6330
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: In the process of one‐step synthesis of methylal via methanol oxidation, the design and research of various dual‐function catalysts are important and studies on the influence of reaction conditions on this type of process are scarce. We explored the influence of reaction temperature, reaction space velocity, and the feed ratio of methanol to air on the catalytic effect of the process based on the Fe‐Mo‐based bifunction catalyst and discovered the most appropriate reaction conditions for the process. Results showed that excessively high reaction temperatures were not conducive to the formation of target product Dimethoxymethane (DMM) and this was verified from the perspective of thermodynamic analysis. At the same time, through Brunaure Emmett Teller (BET), X‐ray diffraction, scanning electron microscope, NH3 ‐temperature‐programmed chemisorption, and Pyridine Fourier Infrared (PY‐FTIR) characterization, analysis of the microstructure and surface characteristics of the catalyst showed that an excessively high reaction temperature caused accumulation of metal oxides on the catalyst surface to block pores and reduce the specific surface area. This also destroyed the active acidic sites on the catalyst surface and weakened the acidity of the catalyst, thereby reducing catalytic activity. Investigation showed that excessively high reaction space velocity caused most of the formaldehyde obtained by catalyzing the initial oxidative dehydrogenation to fail to undergo polycondensation with methanol after desorption in time to obtain DMM, leading to a significant decrease in DMM selectivity. Investigation of the methanol‐air feed ratio showed that when CH3 OH:air = 1.5, the methylal selectivity was highest and catalytic activity had improved. Orthogonal experiments showed that optimal reaction conditions of the process were 663 K, 15 000 h −1 and CH3 OH: air = 0.82. In addition, compared with other bifunctional catalysts of this process, the self‐made Mo:Fe(2)/HZSM‐5 bifunctional catalyst exhibited high stability and carbon deposition resistance under severe operating conditions. Abstract : We explored the influence of reaction temperature, reaction space velocity and the feed ratio of methanol to air on the catalytic effect of the process based on the Fe‐Mo‐based bifunction catalyst and discovered the most appropriate reaction conditions for the process. Discovered the root cause of different reaction conditions that affects the catalytic activity. In addition, compared with other bifunctional catalysts of this process, the self‐made Mo:Fe(2)/HZSM‐5 bifunctional catalyst exhibited high stability and carbon deposition resistance under severe operating conditions.