Natrolite zeolite: A natural and reusable catalyst for one-pot synthesis of α-aminophosphonates under solvent-free conditions

Catalytic Performance of Immobilized Sulfuric Acid on Silica Gel for N-Formylation of Amines with Triethyl Orthoformate

In the search for convenient, green, and practical catalytic methods for the current interest in organic synthesis, a simple, green, and highly efficient protocol for N-formylation of various amines was carried out in the presence of immobilized sulfuric acid on silica gel (H2SO4–SiO2). All reactions were performed in refluxing triethyl orthoformate (65 °C). The product formamides were obtained with high-to-excellent yields within 4 min to 2 h. The current approach is advantageous, due to its short reaction time and high yields. The catalyst is recyclable with no significant loss in catalytic efficiency.

Magnetic ZnO@CuO@Iron ore nanocomposites as a green and highly efficient heterogeneous nanocatalyst for solventless synthesis of α-aminophosphonates

A green novel synthesis of ZnO@CuO@Iron ore nanocomposites as a novel and magnetic heterogeneous nanocatalyst is used for the one-pot synthesis of α-aminophosphonates under solventless conditions. This study benefits from the magnetic iron ore acting as a multi-mineral Lewis acid system, the green properties and the large surface area due to its nanostructure. Moreover, scanning electron microscope analysis confirmed that the nanocatalyst gave an excellent yield and good recyclability; which, even after the 10th cycle of the model reaction retained its potential with no significant loss of catalytic activity.

Zeolites as Acid/Basic Solid Catalysts: Recent Synthetic Developments

The zeolites are porous solid structures characterized by a particular framework of aluminosilicates, in which the incorporation of the Al+3 ions generates an excess of negative charge compensated by cations (usually alkali or alkali earth) or protons. In the latter case, they are employed as catalysts for a wide variety of reactions, such as dehydration, skeletal isomerization and cracking, while the catalytic activity of basic zeolites has not found, up to now, any industrial or whatever relevant application in chemical processes. In the present review, we firstly intend to give an overview of the fundamental chemical composition, as well as the structural features of the zeolite framework. The purpose of this paper is to analyze their key properties as acid, both Lewis and Brønsted, and basic solid support. Their application as catalysts is discussed by reviewing the already published works in that field, and a final remark of their still unexplored potential as green, mild, and selective catalyst is also reported.