The influence of interlayer water on clay catalysts. Interlamellar conversions of 2-methylpropene.
Evidence is provided for two alternative pathways for the reactions undergone by 2-methylpropene between the layers of a sheet silicate catalyst (Al3+-exchanged montmorillonite). This clay, when it initially contains ca. 12% interlayer water, catalyses the addition of either water or methanol to 2-methylpropene to yield, respectively, t-butanol or 2-methoxy-2-methyl propane (methyl tertiary butyl ether, MTBE), whereas the same clay following deliberate dehydration acts as an effective catalyst for the oligomerisation of 2-methylpropene, Similar results are obtained with an Al3+-exchanged synthetic hectorite.