Reactions of silane with zeolitic water

Abstract

A study has been made of reactions of SiH₄ with regulated amounts of zeolitic water in zeolite Na-Y and in Na-mordenite. Between 60 and 200 °C the reaction proceeds more readily in the three-dimensional channel system of zeolite Y than in the one-dimensional channels of mordenite. Nevertheless, a very small deposition of Si (ca. 0.25 wt. %) within mordenite channels reduces the uptakes and rates of sorption of O₂ and N₂ to very low values, while in the modified Na-Y the capacity shown to these gases and to water is decreased only by small amounts, proportionally to the extents of reaction between silane and zeolitic water. This striking difference implies that in mordenite the reaction products are concentrated near the entrances to the channels. Lightly grinding the modified mordenite crystals causes an extremely large increase in the sorption rates of O₂ and N₂. The reaction products formed within the zeolites are not displaced by outgassing at 360 °C, and evidence has been obtained that they are condensation–polymerisation type molecules, probably of low molecular weight.