改性丝光沸石催化剂上合成2,6-二异丙基萘

采用盐酸处理以及水热处理结合酸处理两种方法对氢型丝光沸石(HM)进行脱铝改性,制备了一系列脱铝HM催化剂,并以脱铝HM沸石为载体负载磷钨杂多酸(PW),制备负载杂多酸催化剂,用XRD、FT-IR和NH3-TPD等手段对这些催化剂的结构及酸性质进行了表征,在100mL间歇式不锈钢高压反应釜中对其在萘的异丙基化反应中的催化性能进行了考察。结果发现,随着脱铝深度的增加,HM沸石的酸量下降,酸强度降低,将PW负载于脱铝HM沸石载体上,其酸性质得到改善。上述催化剂的异丙基化反应结果表明,脱铝HM沸石的活性和2,6-DIPN选择性均大大高于未经改性的HM沸石;将PW负载于脱铝HM沸石上,其活性均有不同程度的上升,但对2,6-DIPN的选择性有所下降。催化剂的表征和反应结果显示,催化剂的活性和选择性与其孔结构和酸性质密切相关。

Synthesis of 2,6-diisopropylnaphthalene over modified H-mordenite catalysts

The dealuminated H-mordenites (HM) modified by HCl leaching, and deep hydrothermal treatment combined with HCl leaching were prepared. 12-tungstophosphoric acid (PW) catalysts supported on dealuminated HM were obtained by impregnation at room temperature. The employed catalysts were characterized by XRD, FT-IR and NH_3-TPD techniques, and their catalytic performances were tested in isopropylation of naphthalene in a 100 mL stainless-steel batch reactor. Lower acid amount and weaker acidity are observed for the HM samples after dealumination. However, the introducing of PW onto the dealuminated HM can improve the catalysts' acidity apparently. It is also found that the catalytic activity and selectivity for 2,6-diisopropylnaphthalene (2,6-DIPN) increase greatly over the dealuminated HM catalysts.On the other hand, PW supported on dealuminated HM catalysts exhibits higher activities but slightly lower selectivity for 2,6-DIPN, compared with the dealuminated HM alone. Catalytic performances have also been discussed in relation with the pore structure and acidity of catalysts.