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研究了用电结晶银催化剂由甲醇催化氧化脱氢直接制备浓甲醛的最佳反应条件。结果表明,当反应温度为640℃,氧醇分子比为0.505,惰性气体量为0.6升/分(其中含N_297—95％,CO_23—5％)时,制得的浓甲醛的重量浓度大于50％,醇含量小于3％,符合用于制备聚甲醛的浓甲醛质量要求;在该反应条件下,甲醇的转化率为97.6％,甲醛产率为87.1％,反应选择性为89.2％,空速为43300小时~(-1),时空产率为0.22克分子甲醛/克催化剂·小时。根据热力学和宏观动力学的观点解释了所得的主要实验结果。
The optimal reaction conditions for the direct preparation of concentrated formaldehyde from methanol catalyzed oxidative dehydrogenation using electricity-charged silver catalyst were studied. The results showed that when the reaction temperature is 640 ℃, the ratio of oxygen to alcohol is 0.505, the amount of inert gas is 0.6L / min (containing N297-95%, CO23-5%), the concentration of concentrated formaldehyde is greater than 50 %, The content of alcohol is less than 3%, which meets the quality requirements of concentrated formaldehyde used for preparing polyoxymethylene. Under the reaction conditions, the conversion of methanol is 97.6%, the yield of formaldehyde is 87.1%, the selectivity of reaction is 89.2% 43,300 hours -1, with a space-time yield of 0.22 moles of formaldehyde per gram of catalyst per hour. The main experimental results obtained are explained based on thermodynamics and macro-kinetics.