杂多阴离子的NMR和ESR研究——Ⅱ磷钼钒杂多酸及其镧盐的NMR

NMR AND ESR STUDIES OF HETEROPOLYANIONS Ⅱ NMR of Molybdovanadophosphoric Acid and Its Salts with Lanthanum

具有Keggin结构的磷钼钒杂多酸及其盐是有效的氧化剂.本文通过磷钼钒杂多酸及其镧盐的^(31)p,^(51)V,^(139)La,^(17)O及~1H的NMR测定,并结合红外和差热分析,说明镧的引入对Keggin结构没有影响,但镧对水分子有强的作用力,使阴离子之间存在更多的水分子,从而对催化氧化活性产生了影响.

Molybdovanadophosphoric acid with Keggin structure and its salts are effective catalysts for oxidation reactions. Based on the NMR measurements of 31P, 51V, 139La, I7O and 1H in these catalyst samples in combination with the corresponding IR and DTG determination, it is shown that the addition of lanthanum does not affect the formation of heteropolyacid with Keggin structure. However, lanthanum can exert strong action on water molecules, leading to the existence of more water molecules among the polyanions, which might probably affect catalytically oxidative activity.