Review on Microwave-Matter Interaction Fundamentals and Efficient Microwave-Associated Heating Strategies

Abstract

Microwave heating is rapidly emerging as an effective and efficient tool in various technological and scientific fields. A comprehensive understanding of the fundamentals of microwave–matter interactions is the precondition for better utilization of microwave technology. However, microwave heating is usually only known as dielectric heating, and the contribution of the magnetic field component of microwaves is often ignored, which, in fact, contributes greatly to microwave heating of some aqueous electrolyte solutions, magnetic dielectric materials and certain conductive powder materials, etc. This paper focuses on this point and presents a careful review of microwave heating mechanisms in a comprehensive manner. Moreover, in addition to the acknowledged conventional microwave heating mechanisms, the special interaction mechanisms between microwave and metal-based materials are attracting increasing interest for a variety of metallurgical, plasma and discharge applications, and therefore are reviewed particularly regarding the aspects of the reflection, heating and discharge effects. Finally, several distinct strategies to improve microwave energy utilization efficiencies are proposed and discussed with the aim of tackling the energy-efficiency-related issues arising from the application of microwave heating. This work can present a strategic guideline for the developed understanding and utilization of the microwave heating technology.

Microwave‐accelerated Suzuki Coupling Reaction Catalyzed by Heterogeneous NHC‐Pd

“…In order to overcome this barrier, microwave irradiation can be used as an effective tool in the catalysis. Microwave irradiation heating has several advantages over conventional radiant heating, such as high heating rate, uniform heating, and less energy requirement, resulting in a rapid temperature rise of the entire reaction mixture . Therefore, the microwave irradiation has emerged as a powerful technique towards sustainable chemistry because it offers efficient, safe, and clean eco‐friendly processes…”

“…Microwave irradiation heating has several advantages over conventional radiant heating, such as high heating rate, uniform heating, and less energy requirement, resulting in a rapid temperature rise of the entire reaction mixture. 5 Therefore, the microwave irradiation has emerged as a powerful technique towards sustainable chemistry because it offers efficient, safe, and clean eco-friendly processes. 6 We have previously reported that silica gel-supported Nheterocyclic carbene (NHC)-Pd complex 1 can serve as an active catalyst for the Suzuki reaction.…”

Chemical composition and antibacterial activity of Dracocephalum kotschyi essential oil obtained by microwave extraction and hydrodistillation

“…But microwave energy, with a frequency of 2.45 GHz, is well known to have a significant effect on the rate of various processes in the chemical and food industry. [28] It is important to recognize that the energy delivered by microwaves is insufficient for breaking covalent chemical bonds. During microwave at highfrequency heating, many material properties affect the heating performance.…”

Tuning, Impedance Matching, and Temperature Regulation during High‐Temperature Microwave Sintering of Ceramics

“…As a result, the energy is transferred through the material by direct microwave-matter coupling, not as a thermal heat ux. Consequently, the rate of heating is often high, and the uniformity of heat distribution is greatly improved [9]. All these features undeniably contribute to the high e ciency of the microwave thermal process.…”