沸石分子筛催化剂上萘的择形异丙基化反应性能

Catalytic Performance of Zeolite Catalysts for Shape Selective Isopropylation of Naphthalene

研究了HY ,Hβ ,HM和HZSM 5沸石分子筛对萘择形异丙基化反应的催化性能 .结果发现 ,这些沸石分子筛的活性顺序为HY >Hβ >HM >HZSM 5 ,对 2 ,6 二异丙基萘的选择性顺序为HM >Hβ >HY .除沸石分子筛的酸量与酸分布外 ,其孔道结构与大小是影响萘异丙基化反应的主要因素 .脱铝能选择性地降低沸石外表面的酸性 ,且对沸石的催化性能有较大影响 .常压水蒸气脱铝结合强酸再处理有利于催化剂催化性能的提高 .提高反应温度有利于萘的转化 ,但温度过高会引发许多副反应 ,适宜的反应温度约为 5 2 3K .反应时间对产物分布的影响不明显 .异丙醇 /萘摩尔比应小于 2 .

Naphthalene alkylation with i PrOH was studied over HM, HZSM 5, Hβ and HY zeolites. It was found that the catalytic performance of the catalysts for naphthalene conversion decreased in the order of HY>Hβ>HM>HZSM 5, but for the selectivity to 2 isopropyl naphthalene (IPN) and 2,6 diisopropyl naphthalene (DIPN) in the order of HM>Hβ>HY. It is quite evident that the catalytic activity and selectivity observed for isopropylation of naphthalene strongly depends on the pore structure of the zeolites except their acidity. The product distribution varied with the reaction conditions and Si/Al ratio of the zeolites. Naphthalene conversion decreases slightly or remains unchanged with mild dealumination, but the selectivity especially for 2,6 DIPN increases markedly with steam dealumination. Steam treatment and hydrochloric acid extraction can increase the activity and selectivity of the zeolite catalysts. The conversion and selectivity increase slightly with reaction time but markedly with reaction temperature. The reaction condition n ( i PrOH)/ n (C 10 H 8)=2, θ =250 ℃ and t =4 h may be satisfied for naphthalene isopropylation on mordenite.