Correlating Lewis acid activity to extra-framework aluminum species in zeolite Y introduced by Ion-exchange

Lewis acidity was introduced into zeolite Y (Si/Al = 30) by a facile ion-exchange of aluminum cations followed calcination. X-ray diffraction and nitrogen physisorption suggest that the zeolitic framework is retained after these treatments. With an increase in total extra-framework modified zeolites, there pronounced number acid sites, as illustrated FTIR spectroscopy adsorbed pyridine carbon monoxide, whereas no significant change Brønsted sites observed. Likewise, catalytic activity, i.e. conversion rate reaction for MPV reduction 4-tert butyl cyclohexanone using isopropanol over catalysts, improved considerably ion-exchange. A quantitative agreement observed between concentration species with content from pyridine-FTIR initial rates. This illustrates newly acidic adopt octahedral coordination under conditions NMR measurement are responsible enhanced activity exchanged zeolites. The preservation further endorses charge neutrality complexes.