ABSTRACT
The green synthesis of chemicals and materials has attracted worldwide research attention in recent years. The number of scientific publications and patents on green synthesis has increased 20 times during the past decade. The focus was on making the processes environmentally friendlier as well as material/energy utilization efficient. Green synthesis has used the unique opportunities provided by the microwave irradiation in material synthesis. Microwaves are a nonionizing radiation, lies in between the infrared and radio waves with a wide frequency range of 0.3 to 300 GHz corresponding to the wavelengths of 0.001-0.3 m (energy = 10-5-0.01 eV). The maximum portion of the microwave spectrum is allocated for the telecommunication and radar technology. In order to avoid the interference with the telecommunications and radar technology, there is a specific type of frequencies in the microwave region namely, 27.12 MHz, 915 MHz, and 2.45 GHz that are used for industrial, scientific, and medical applications, respectively, and they are collectively called as ISM bands. Among them, the frequency of 2.54 GHz is most commonly employed in the design of microwave ovens for heating and research applications. There are many alternatives to the conventional heating, the notable among them are mechanochemical, ultrasound, microwave, photochemical, and X-ray or gamma-radiation mediated methods. The microwave-assisted synthesis has received a special attention from the scientific community and there is extensive reported literature on this subject [1-16]. The divergent fields that have been benefited by the microwave irradiation are synthetic organic chemistry, polymer chemistry, material science, nanotechnology, biochemical processes, peptide synthesis, food processing and analytical applications.
