ChemInform Abstract: The Growing Impact of Niobium in Organic Synthesis and Catalysis

Abstract

Review: 55 refs.

Methyl Esters Production by Heterogeneous Catalyst Mixtures of CaO/Nb2O5 with Simulation of Analysis of Environmental Impacts

“…34 Some niobium compounds (niobium ammonium oxalate, niobium oxide and niobium pentachloride) have been studied in the production of biodiesel, involving its application as a Lewis acid. [35][36][37] The niobium oxide, Nb 2 O 5 .nH 2 O, has both Lewis acid sites (which increase with the pretreatment temperature rise to over 500 °C and then decrease at higher temperatures), and Brønsted acid sites (which are more abundant at 100 °C and decrease at elevated temperatures) on its surface. 37,38 There is a consensus that it is strategic for Brazil to diversify the sources of raw materials for biodiesel production.…”

Efficient one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives promoted by niobium pentachloride

“…NbCl 5 forms chloro-bridged dimers in its solid state in which each niobium atom is surrounded by a distorted octahedron of chlorine atoms. NbCl 5 is highly electrophilic and can act as a Lewis acid, promoting several organic transformations (Batista et al, 1997;Kobayashi et al, 2000;Constantino et al, 2001Constantino et al, , 2004Constantino et al, , 2005Constantino et al, , 2007Andrade, 2004;da Silva-Filho et al, 2005Andrade & Rocha, 2006;Wang et al, 2007;Polo et al, 2008;Cai et al, 2010;Hou et al, 2010Hou et al, , 2011Lacerda et al, 2012;Liu et al, 2013;Martins et al, 2013;dos Santos et al, 2013;Bian et al, 2014;Nasseri et al, 2014).…”

Synthesis of Quinoline Derivatives by Multicomponent Reaction Using Niobium Pentachloride as Lewis Acid

“…As part of our research work on synthetic methodologies using NbCl 5 in a variety of reactions , in this work, we described our studies in the multicomponent reactions between benzaldehyde, aniline derivatives, and phenylacetylene, for the synthesis of quinoline derivatives, in the presence of NbCl 5 .…”