Influence of aluminium incorporation in the preparation of zirconia-pillared clay and catalytic performance in the acetalization reaction

Abstract

The exchange reaction of Na-bentonite with zirconium pillars gives products which suffer from a loss of crystallinity, with basal spacing about 18 Å and surface area of 200 m2 g–1. Aluminium introduced in different amounts in the zirconium intercalated solution leads to an improvement in the stability and crystallinity of zirconia-pillared clays (Zr-PILCs) and creates pillared clays with new properties. Adding a small amount of Al (10 molar %) leads to an increase of d001 from 18 Å to 20.5 Å and an increase of the percentage of introduced zirconium from 16.71 to 21, expressed as ZrO2 wt.%, accompanied by an increase of the Brönsted and Lewis acidic sites. The acetalization of acetone with ethylene glycol was studied in order to compare the activity of PILCs. The results show that the yield of the aforementioned reaction depends strongly of the composition and acidity of the catalyst.

Catalytic wet peroxide oxidation of phenol over Ce-Zr-modified clays: Effect of the pillaring method

“…This bentonite has been thoroughly characterized in previous works [11][12][13][14]. The impurities are mainly quartz and calcite.…”

Preparation of ZrO2/Al2O3-montmorillonite composite as catalyst for phenol hydroxylation

“…Studies in the literature related to zirconia-pillared clay and the combination of zirconia with aluminum-pillared montmorillonite are limited, although ZrO 2 is a well-known active metal oxide catalyst utilized in many chemical reactions. Previous investigations have revealed that ZrO 2 pillarization significantly affected the montmorillonite’s catalytic activity in some organic reactions, including the linear alkylation of benzene, acylation of diol, and acetylation, while ZrO 2 dispersed into aluminum-pillared saponite has been used for NOx selective catalytic reduction (SCR) and phenol hydroxylation [13–16] . Al-pillared montmorillonite enhances the catalytic activity of ZrO 2 , while the ZrO 2 increases the catalyst stability.…”