杂多酸的硫化作用

以ＩＲ光谱和程序升温硫化方法对近年来催化研究和应用较多的几种杂多酸在Ｈ２Ｓ作用下的硫化过程进行了研究，在ＳｉＷ１２，ＰＷ１２和ＰＭｏ１２三种杂多酸中，ＰＭｏ１２最易发生硫化作用，其两种桥氧化端氧易化的倾向也最大，ＰＷ１２次之，在初始硫化阶段，杂多酸中的部分氧原子在维持其Ｋｅｇｇｉｎ骨架结构情况下被硫原子取代，在这一条件下硫氧交换是可逆的，对于ＰＭｏ１２，可维持其Ｋｅｇｇｉｎ结构的温度接的室温，对于

Sulfurization of Hyteropoly Acids

The sulfUIization of several heteropoly acids (HPA), which have been applled as catalysts frequently in recent years, have been studied by IR spectra and temperature programmed sulPhurization technology. The result showed that sulphurization of PMo12 is the easiest one among the three kinds of HPA (PMo12, PW12, SiW12). In addition,The trend that the two kinds of bridged oxygen in HPA were substituted by sulfur atoms prior to terAnnal oxygen, is PMo12 >PW12 >SiW12. In the iintial stage of sulphUrization,some of oxygen atoms in HPA are substituted by sulfur atoms reversibly and the Keggin structure has been preserved during this process. For PW12 and SiW12, the Keggin structure can be preserved until the sulphurization temPerature has been raised to 673K,and for the PMo12, this temPerature is near room temPerature. When the temPerature exceed those mentioned above in the sulphUIization process, the exchange between sulfur and oxygen become irreversible, and deep sulphurization of HPA 1nay be accompanied with disintegration of the Keggin anion skeleton.