含锆层柱蒙脱石对1,2,4三甲基苯歧化反应的催化作用

DISPROPORTIONATION OF 1,2,4 TRIMETHYLBENZENE OVER Zr CONTAINING PILLARED MONTMORILLONITE

用离子共聚法合成了硅锆层柱蒙脱石（ＳｉＺｒＰＩＬＭ）和铁锆层柱蒙脱石（ＦｅＺｒＰＩＬＭ），考察了它们对１，２，４三甲基苯（１，２，４ＴｒＭＢ）歧化反应的催化性能．１，２，４ＴｒＭＢ在催化剂样品上可发生歧化反应和异构化反应，歧化反应选择性达８０％以上．随着催化剂预处理温度的提高，１，２，４ＴｒＭＢ转化率下降，歧化反应选择性和四甲基苯（ＴｅＭＢ）中１，２，４，５ＴｅＭＢ含量则升高．催化剂对１，２，４ＴｒＭＢ歧化反应有择形催化作用，１，２，４，５ＴｅＭＢ和间二甲苯、邻二甲苯为主要产物，并且其含量偏离其热力学平衡组成，ＴｅＭＢ中１，２，４，５ＴｅＭＢ的含量在８５％以上．

The hydroxy Si Zr and Fe Zr pillared montmorillonites (PILM) were prepared by cross linking montmorillonite with hydroxy zirconium tetramer [Zr 4(OH) 14 (H 2O) 10 ] 2+ doped by silica gel or FeCl 3 solution. The thermal stability and acidity of PILM were investigated by XRD, BET and NH 3 TPD methods. The Zr containing PILM in this study possessed high thermal stability up to 650℃. At 650℃ PILMs have surface area about 142～295 m 2/g and basal spacing ( d 001 ) about 1 60～1 89 nm. The catalytic activity and selectivity of PILM are related to its acidic property. The PILM shows higher selectivity for 1,2,4 TrMB disproportionation than that for 1,2,4 TrMB isomerization. With increasing pretreatment temperature the catalytic activity decreased remarkably, while disproportionation selectivity and percentage of 1,2,4,5 TeMB in TeMB isomers increased. 1,2,4,5 TeMB and m xylene are main products from 1,2,4 TrMB disproportionation. PILM shows shape selective property.