柱撑阴离子粘土的合成表征及催化性能研究（Ⅳ）──ZnAl－SiW_（11）和ZnAl-SiW_（11）Z的合成及稳定性研究

Study on Synthesis, Characterization and Catalysis of Pillared Ainon Clay (Ⅳ)──Synthesis and Stability of the ZnAl-SiW_(11) and ZnAl-SiW_(11)Z

用离子交换法合成了杂多阴离子柱撑阴离子粘土ＺｎＡｌ-ＳｉＷ１１和ＺｎＡｌ-ＳｉＷ１１Ｚ（Ｚ＝Ｃｏ２＋，Ｎｉ２＋，Ｃｕ２＋）．ＸＲＤ和ＩＲ测定结果表明，这些层柱化合物的通道高度是１．４６×１０-７ｃｍ，层间阴离子保持它们的Ｋｅｇｇｉｎ结构．它们在空气中热分解序列为：ＺｎＡｌ-ＳｉＷ１１Ｎｉ（３４７℃）＞ＺｎＡｌ-ＳｉＷ１１Ｃｏ（３４１℃）＞ＺｎＡｌ-ＳｉＷ１１Ｃｕ（３３５℃）＞ＺｎＡｌ-ＳｉＷ１１（３２９℃）＞ＺｎＡｌ-（２９０℃），在沸腾水溶液中稳定存在的ｐＨ值范围是３．６～７．５．

Layered double hydrotalcites pillared by hereropolyoxometates, ZnAl-SiW11and ZnAl-SiW11Z (Z=Co2+, Ni2+ , Cu2+ ) have been synthesied by anion exchange. The spectra of powder X-ray diffraction and IR show that the compounds are layered compounds with gallery heights 1. 46×10-7cm, amions entering the layer remain their Keggin Structure. The series of decomposition temperature in air is ZnAl-SiW11Ni (347℃)>ZnAl-SiW11Co (341℃) >ZnAl-SiW11Cu (335℃) >ZnAl-SiW11 (329℃) >ZnAl-(290℃ ). The XRD patterns of the compounds which were treated in the boiling solution with different pH for 2 hr show the layer structure are stable in the pH range of 3. 6￣7. 5.