Synthesis of Some Kinds of Metallosilicates by Atom-Planting Method and Their Catalytic Properties

以高硅MFI型沸石、脱铝丝光沸石和金属氯化物为原料，采用原子植入法制备了几种金属硅酸盐。当金属氯化物蒸气在较高温度下与高硅沸石接触时，金属阳离子可以占据沸石骨架中的缺陷位置，质子交换的金属硅酸盐的酸性取决于插入骨架的三价金属阳离子的种类。测定了几种金属硅酸盐的酸强度顺序：As-&GT；Ga-&GT；Fe-&GT；In-&GT；Sb-&GT；As-。当这些金属硅酸盐用于单烷基苯烷基化反应时，生成的二烷基苯异构体比例可达80-100%。从相同孔径、不同酸强度的金属硅酸盐催化剂的实验结果可以看出，过渡金属阳离子以四面体的形式存在于沸石骨架中，不易被还原和氧化，是通过过渡态限制择形生成的。因此，过渡金属阳离子在沸石骨架中的催化性能可能不同于在氧化物和络合物中的催化性能。沸石骨架中以三价态存在的铁阳离子表现出较高的氧化脱氢活性和较低的低碳烷烃完全氧化活性，而氧化铁具有较高的低碳烷烃完全氧化活性。另一方面，采用原子植入法制备了具有丝光沸石结构的钛硅酸盐，对苯环与过氧化氢的液相羟化反应表现出了较高的催化活性，是制备金属硅酸盐的一种很好的方法，对某些反应具有独特的催化性能。

Some kinds of metallosilicate could be prepared by Atom-Planting method using highly silicious MFI type zeolite and dealuminated mordenite, and metal chlorides. When vapor of metal chloride contacts with highly silicious zeolites at the higher temperatures, the metal cation can occupy the defect sites in zeolite framework.The acidity of metallosilicates ion-exchanged by proton deferred to the kind of trivalent metal cation inserted into the framework. The order of acid strength of some metallosilicates was measured as follows ;As-> Ga-> Fe-> In-> Sb-> As-When these metallosilicates were used as a catalyst for the alkylation of monoalkylbenzene, the fraction of para isomer in dialkylbenzene produced reached 80-100%. It can be concluded from the results obtained by using metallosilicate catalysts with same pore window size but different acid strength that para isomer is shape-selectively produced through the transition state restriction.The transition-metal cation inserted into the zeolite framework was a tetrahedral state and was not easily reduced nor oxidized. Therefore, it is expected that the catalytic properties of transition-metal cations in zeolite framework would be different from those in oxides and coplex compounds. Iron cation with tri-valent state in zeolite framework showed the high activity for the oxidative dehydrogenation and the low activity for the complete oxidation of lower paraffins, while iron oxide showed the high activity for the complete oxidation of lower paraffins. On the other hand, titanosilicate with mordenite type structure could be prepared by Atom-Planting method, and showed high catalytic activity for the liquid phase hydroxylation of benzene ring with hydrogen peroxide.From these results it is concluded that Atom-Planting is a good method for the preparation of metallosilicates and these metallosilicates will show the unique catalytic properties for some reactions.