Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

Abstract

In situ MAS NMR studies on the monitoring of hydrothermal synthesis of zeolites are reviewed. The first part of the review contains information on the experimental techniques used for the in situ NMR studies in static and MAS conditions. In the second part, the main capabilities of the in situ ¹ H, ¹¹ B, ¹³ C, ¹⁴ N, ¹⁹ F, ²³ Na, ²⁷ Al, ²⁹ Si and ³¹ P MAS NMR for the elucidation of the mechanism of hydrothermal synthesis of zeolites are examined and the data on NMR lines identification are summarized. In the last part the main application areas of the techniques are considered and illustrated with examples taken from the mechanistic studies of zeolites A, X, MFI and BEA synthesis. A cross-reference index between the materials studied, the experimental approaches used, the mechanistic information obtained, and the corresponding literature sources is established.

Keywords: hydrothermal synthesis; in situ MAS NMR; mechanisms of nucleation and crystal growth; molecular sieves; zeolites.