Al-27 NMR study of the effect of aqueous and methanolic media on the distribution of tetraphenylammonium aluminosilicate species

摘要

The effects of tetraphenylammonium (TPhA) on the equilibrium distribution of aluminosilicate oligomers in aqueous and methanolic alkaline aluminosilicate solutions are investigated using Al-27 NMR spectroscopy. Alkaline solutions containing both silicate and aluminate ions are of considerable research interest inter alia because of their involvement in the synthesis of zeolites. In the present work, we use Al-27 NMR to characterize alkaline aqueous and methanolic tetraphenylammonium (TPhA) aluminosilicate solutions with different Al/Si ratios. Tetraphenylammonium (TPhA) is used as a cation template and no alkalie metals are used for the preparation of aluminosilicate solutions. The distribution of aluminosilicate species is affected by the presence of the alcohol such as methanol and the method of mixing the silicate and aluminosilicate solutions. To understand the reaction between silicate and aluminate ions in this system, the evolutions of Al-27 NMR spectra with time are investigated.