Microwave dielectric heating in synthetic organic chemistry

Abstract

First described more than two decades ago, microwave-assisted organic synthesis has matured from a laboratory curiosity to an established technique that today is heavily used in both academia and industry. One of the most valuable advantages of using controlled microwave dielectric heating for chemical synthesis is the dramatic reduction in reaction times: from days and hours to minutes and seconds. As will be explained in this tutorial review, there are many more good reasons why organic chemists are nowadays incorporating dedicated microwave reactors into their daily work routine.

Microwave assisted synthesis of MnO2 on nickel foam-graphene for electrochemical capacitor

“…The microwave irradiation induces a volumetric heating by direct coupling of microwave energy with the molecules that are present in the reaction chamber. This increases the temperature of the whole liquid volume in the chamber simultaneously, compared with conventionally heating system, where the reaction chamber in contact with the hot vessel walls is heated first [36,37]. Figure 1 also occurs.…”

“…When reaction chamber is irradiated, the dipoles or ions in the sample align themselves in the direction of applied electric field. When the applied field oscillates, the dipole or ion field realigns itself with the alternating electric field thereby losing energy in the form of heat through friction and dielectric loss [36]. The microwave irradiation induces a volumetric heating by direct coupling of microwave energy with the molecules that are present in the reaction chamber.…”

Nano-MgO: An Efficient Catalyst for the Synthesis of Formamides from Amines and Formic Acid Under MWI

“…A number of formylating reagents as well as methods are available in the literature [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Acetic formic anhydride is a well known formylating reagent [10], but is sensitive to moisture.…”

Synthesis of novel benzimidazole-diindolylmethane hybrid compounds within the green chemistry context

“…On the other hand, microwave irradiation is well known to promote the syntheses of a great variety of compounds, [18][19][20] where chemical reactions are accelerated because of selective absorption of microwaves by polar molecules and the coupling of these two factors under solvent-free conditions has received notable attention. 21 A literature survey reveals examples of specific reactions, which do not occur under conventional heating, but could be possible by microwave irradiation.…”