Organic synthesis using clay catalysts

Abstract

Gopalpur Nagendrappa teaches organic chemistry at Bangalore University. His work includes organic synthesis and reaction mechanisms mainly in the area of organosilicon chemistry. Presently he is also working on organic synthesis under solventfree conditions and using clay-catalyses.

Improved methodologies for synthesis of prenylated xanthones by microwave irradiation and combination of heterogeneous catalysis (K10 clay) with microwave irradiation

“…As this catalyst can be easily separated from the reaction mixture and can be regenerated, the purification procedures are usually simple. 9,10 Furthermore, the coupling of MW irradiation with the use of inorganic solid supports such as Montmorillonite K10 clay, either with solvent or under solvent-free conditions, can also provide a chemical process with inherent advantages such as enhanced reaction rates, high yields, ease of manipulation, and selectivity. 11 Here we report the microwave-assisted synthesis of two oxyprenylated xanthones (4 and 6), along with four diprenylated byproducts (5,(7)(8)(9) from the simple hydroxylated xanthones (1 and 2) and prenyl bromide, as well as the synthesis of dihydrofuranoxanthones (11)(12)(13) and two new rearranged prenylxanthones (14,15) from the oxyprenylated xanthones 4 and 6 ( Fig.…”

Kalium Hydroxide/Zirconia Pillared Bentonite for Palm Oil Transesterification

“…The use of clay as the heterogeneous catalyst has been more promising because of its positive effect including the ease of separation process between the product and the catalyst, easy to regenerate, more efficient, cheap and environmental friendly [2][3][4][5] . The use of heterogeneous solid catalyst from modified clay has been proven to be used in biodiesel production through transesterification process 6 .…”

Performance of Recycled K10 Montmorillonite Catalyst in the Alcoholysis of Epoxidised Palm Olein

“…Usually, this catalyst can typically be recovered and recycled. The structure of K10 montmorillonite catalyst was studied by Nagendrappa (2002) (Figure 1). The chemical formula of K10 montmorillonite is Al 2 Si 4 O 10 (OH) 2 .nH 2 O.…”