Encouragements for the Use of Microwaves in Industrial Chemistry

• Published in: Chemical record 2019-01, Vol.19 (1), p.51-64
• Main Authors: Nagahata, Ritsuko, Takeuchi, Kazuhiko
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Condensation polymerization; Energy conservation; Esterification; Heating; Industrial applications; Industrial plants; Microwave heating; microwave-assisted esterification; microwave-assisted polymerization; Microwaves; Organic chemistry; polycondensation; Scaling
• ISSN: 1527-8999; 1528-0691
• DOI: 10.1002/tcr.201800064

Microwave travels at the speed of light, and transfers energy solely to materials. This holds great promise for energy conservation in industrial processes. However, due to differences with common heating principles, and misunderstanding of the correct way to handle them, the effectiveness of microwaves has been underestimated, and development of technologies using microwaves often stops due to this. This paper has focused on the use of microwave heating for organic/polymer synthesis, specifically for a highly effective condensation reaction and for use with ionic reactants. In addition to covering the process of ascertaining which reactions are suitable for the application of microwave heating, and introducing studies on scaling these up, this paper covers points of caution, especially those relating to the all‐important measurement/control of temperature. Based on their accumulation of expertise in the area, the authors present the design for equipment/plants for industrial use and introduce their research into the practical application of such technology. Microwaves can be said to float in space; they do not “see” the surrounding air or glass‐like containers and pass directly into the reactants. When using metals, directly irradiating the reaction with microwaves through a window cut into the reaction vessel will cause the internal walls of the vessel not to absorb any energy, and the microwaves are only able to act on the necessary substances. In other words, if used properly, this technology can be used for extremely high efficiency industrial production methods that do not waste any more energy than is absolutely required.