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低分子量的胺是合成含氮有机化合物的重要原料 .以NaM、HM、NaHM和NaKHM为催化剂 ,采用CH3 OH/NH3 _TPD、XPS、比表面积和孔容分布测量等手段研究了甲醇胺化反应 .结果表明 :胺化产物分布受氨NH3 的预吸附和甲胺 (MMA)、二甲胺 (DMA)及三甲胺 (TMA)的择形脱附控制 .由于沸石孔道中部分孔穴被氨填充和堵塞 ,导致孔体积变小、空间位阻增大 ,难以生成分子较大的三甲胺 (TMA) .NH3 预吸附造成的另一个结果是预吸附过程中Na+ 和K+ 由分子筛体相向孔口迁移 .这些位于孔口的金属阳离子有利于甲胺和二甲胺的选择脱附 ,而不利于三甲胺分子从孔口的有效脱附 ,因而强化了三甲胺到二甲胺的歧化反应 ,其结果是增大了二甲胺的选择性 ,使产物分布符合预先设想 .
Low molecular weight amines are the important raw materials for the synthesis of nitrogen-containing organic compounds. The amination of methanol was studied using CH3OH / NH3-TPD, XPS, specific surface area and pore volume distribution measurements with NaM, HM, NaHM and NaKHM as catalysts. The results showed that the distribution of aminated products was controlled by pre-adsorption of NH3 and selective desorption of methylamine (MMA), dimethylamine (DMA) and trimethylamine (TMA) , Resulting in a decrease in pore volume and increased steric hindrance, making it difficult to generate large-molecule trimethylamine (TMA). Another consequence of pre-adsorption by NH3 is the migration of Na + and K + from the molecular sieve to the orifice during pre-adsorption The metal cation located in the orifice is conducive to the selective desorption of methylamine and dimethylamine, which is not conducive to the effective desorption of trimethylamine molecules from the orifice, thus enhancing the disproportionation reaction of trimethylamine to dimethylamine. As a result, Large dimethylamine selectivity, the product distribution in line with pre-imagined.