Infrared evidence of three distinct acidic hydroxyls in defect-free HY faujasite.

Trimethylamine (TMA) and ammonia (NH(3)) were coadsorbed over a free extraframework aluminum (EFAL) HY zeolite, which allowed us to distinguish at least three different acidic hydroxyls in the faujasite structure.

Trimethylamine as a probe molecule to differentiate acid sites in Y-FAU zeolite: FTIR study.

In heterogeneous catalysis acidity has a very important influence on activity and selectivity: correct determination of acidic properties is a base to improve industrial processes. The aim of this work was to study trimethylamine (TMA) as a probe molecule able to distinguish between the different Brønsted acid sites in zeolitic frameworks. Our work mainly focused on faujasite-type zeolites because the HY zeolite is one of the most used acidic catalysts in industrial processes.