预处理对天然丝光沸石合成二甲胺催化性能的影响

Effect of Pretreatment on Catalytic Performance of Natural Mordenite for the Synthesis of Dimethylamine

为了提高甲醇气相胺化合成二甲胺的选择性和催化活性,研究了处理液类型和浓度及焙烧温度等预处理条件对天然丝光沸石催化性能的影响．结果表明:酸处理可降低沸石表面活性中心数目但提高活性中心的酸强度;沸石的催化活性与酸强度间存在对应关系,而沸石的选择性主要受择型效果控制,酸中心数目、酸强度和比表面积对选择性影响不大;焙烧对沸石晶型结构影响较大,温度过高晶型被破坏;优化的预处理条件为处理液盐酸浓度2 mol／L,焙烧温度400℃．

For improving the selectivity and catalytic activity of methanol for the synthesis of dimethylamine, the effects of pretreatment conditions, including solvent type （ST）, concentration and roasting temperature （RT） on catalytic performance of natural mordenite （NM） were studied. The results show that acid treatment can decrease the number of active center （AC） but increase acidity in AC on NM surface; there is a corresponding relationship between catalytic activity and acidity of NM, while NM selectivity was mainly controlled by shape-selectlve effect and the selectivity was affected by the number of AC, acidity and specific area of NM to only a small extent; crystall structure was affected by RT and can be destroied at too high RTs; optimum pretreatment conditions of 2 mol/L of hydrochloric acid and 400 ℃ RT are achieved.