Heterogeneous Montmorillonite Research Articles

Montmorillonite clay-based heterogenous catalyst for the synthesis of nitrogen heterocycle organic moieties: a review.

The use of montmorillonite clay as solid catalyst has grabbed much attention in the liquid phase reactions for organic synthesis. In recent years, there has been a lot of interest in organic synthesis using montmorillonite-based composites, especially in the synthesis of heterogeneous nanoparticles. Due to the robust and green nature of montmorillonite-based nanocatalysts, it has been widely used in N-heterocyclic reactions. In this review, we have concentrated on the reports pertaining the use of montmorillonite-based nanocatalyst in the synthesis of N-heterocycles, a category of organic compounds with excellent biological properties. This manuscript is arranged by the types of N-containing heterocycles synthesized using montmorillonite-based composite as catalysts including polycyclic spirooxindoles, heterocyclic propargylamine, indole-based heterocycles, quinoline and its derivatives, six-membered N-heterocyclic-based compounds and five-membered N-heterocyclic-based compounds. Special attention was given to the structural stability under experimental parameters of the montmorillonite-based composite with the incidence of metal leaching and reusability. Finally, along with recent developments, new findings in heterogeneous montmorillonite (Mt)-based catalysis have also been addressed.

From Conventional Lewis Acids to Heterogeneous Montmorillonite K10: Eco-Friendly Plant-Based Catalysts Used as Green Lewis Acids.

The concept of green chemistry began in the USA in the 1990s. Since the publication of the 12 principles of this concept, many reactions in organic chemistry have been developed, and chemical products have been synthesized under environmentally friendly conditions. Lewis acid mediated synthetic transformations are by far the most numerous and best studied. However, the use of certain Lewis acids may cause risks to environmental and human health. This Review discusses the evolution of Lewis acid catalyzed reactions from a homogeneous liquid phase to the solid phase to yield the expected organic molecules under green, safe conditions. In particular, recent developments and applications of biosourced catalysts from plants are highlighted.

ChemInform Abstract: A Highly Efficient Heterogeneous Montmorillonite K‐10‐Supported Palladium Catalyst for Suzuki—Miyaura Cross‐Coupling Reaction in Aqueous Medium.

A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.

A highly efficient heterogeneous montmorillonite K‐10‐supported palladium catalyst for Suzuki–Miyauracross‐coupling reaction in aqueous medium

A heterogeneous montmorillonite K‐10‐supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross‐coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross‐coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.

Effect of immobilization and activity analysis of water oxidation catalysts adsorbed into clay

The catalytic activity of a trinuclear Ru complex; ([(NH 3) 5Ru-O-Ru(NH 3) 4-O-Ru(NH 3) 5] 6+) (Ru-red) for water oxidation was investigated both in a homogeneous aqueous solution system (AS) and a heterogeneous montmorillonite adsorbed system (clay). It was shown that water oxidation by the catalyst in the clay to evolve O 2 is a competitive reaction with bimolecular decomposition of the catalyst. The bimolecular decomposition was remarkably suppressed in the clay as compared with the aqueous solution, and the catalytic activity was maintained under higher concentration conditions. This was ascribed to the immobilization and isolation of the complex in the clay. The catalytic activity was analyzed by a model equation based on intermolecular distance distribution of the complex. The catalytic activity ( k O 2 ) and the critical decomposition distance ( r d) were obtained as 1.7×10 −2 s −1 and 2.39 nm, respectively.