Selectivity in the conversion of n-heptane on an Al-PILC modified with Ga

From Microporous to Mesoporous Molecular Sieve Materials and Their Use in Catalysis

“…In this case the slightly larger ionic radius of the Ga 3+ ion, makes the GaAl 12 structure more symmetric than its corresponding Al 13 oligomer, and consequently, the former should be thermodynamically favored over the Al 13 and Ga 13 and also more thermally stable. Thus, montmorillonite has been pillared with GaAl pillars which were synthesized with different Ga/Al ratios. − The layer spacing varied from 1.8 to 2.0 nm at room temperature and between 1.7 and 1.8 nm after calcination at 500 °C. As expected, the thermal and hydrothermal stability of the GaAl PLS was higher than that of the clay pillared with Al alone.…”

“…Thus, montmorillonite has been pillared with GaAl pillars which were synthesized with different Ga/Al ratios. [45][46][47][48] The layer spacing varied from 1.8 to 2.0 nm at room temperature and between 1.7 and 1.8 nm after calcination at 500 °C. As expected, the thermal and hydrothermal stability of the GaAl PLS was higher than that of the clay pillared with Al alone.…”

“…It was described above that GaAl pillars led to highly thermally and hydrothermally stable PLS materials. [45][46][47][48] With regard to their acid properties, it has been found that the highest total acidity, measured by pyridine adsorption, occurs on PLS with large Al/Ga ratios. However, when the samples are heated at high temperatures only Lewis acid sites are present, indicating that the Brønsted sites of the solids have been dehydroxylated.…”

Relationship between the Surface Properties and the Catalytic Performance of Al-, Ga-, and AlGa-Pillared Saponites

“…Thus, the polycation should be formulated as [GaO 4 Al 12 (OH) 24 -(H 2 O) 12 ] 7+ . The use of mixed Al-Ga solutions for intercalation purposes was described by several authors, mainly for the intercalation of montmorillonite [7][8][9][10][11][12][13][14][15][16] and also beidellite. [16][17][18] It was shown that the pillaring process occurred similarly as observed for aluminum polycation solutions.…”

“…However, the Gacontaining solids exhibited higher thermal stability in comparison with their Al-containing counterparts. The use of AlGa-pillared clays as catalysts for various reactions has been described, such as n-heptane isomerization, 10,11 propane dehydrogenation to propene, 13 and benzene alkylation with ethylene. 14 These materials also were considered as supports for the preparation of metal-supported catalysts; this was the case for Pt/AlGa-pillared montmorillonites used as n-heptane isomerization catalysts.…”