ABSTRACT
The increase in the energy demand forces human kind to find out new alternatives to existing sources. Engineering materials applicable in medical, industrial, and technological field have been developed to great extents during the past decade. Several physical as well as chemical reactions are practiced in order to synthesize new materials for various applications. However, the disadvantages of these methods are not simple and cannot be discarded easily. The long reaction time needed for the reactions, use of harmful and toxic catalysts, use of chlorinated, and often high boiling point solvents and so on are only a few of them. Most of the preparation methods involve the use of toxic solvents, release of unwanted pollutants to the atmosphere, and complicated steps. In order to alleviate the impact of these problems, cleaner and safer methods were developed. Earlier scientists were concentrating on the yield, easiness, and
fastness of reactions, but now the world is looking for environmental friendly methods as well. Due to this fact, apart from the lower fabrication costs and improved material properties, environmental concern is also anticipated for the synthesis of new materials. All the processes eliminating the use of harmful chemicals and thus not imposing any problem to living cells are regarded as green methods. Such eco-friendly methods include the use of ionic liquids, microwave irradiation, solid phase syntheses, and so on. The influence of ionic liquids and microwave assistant green methods in organic synthesis has been well explained by Palou et al. [1]. An example of green chemical method is seen in rail transportation system. This mode of transportation emits a large amount of green house gases to the atmosphere, and this can be alleviated by establishing a green method. By using aluminum alloy, composite material, and sandwich panel for rail car bodies and interiors and thereby adopting a lightweight material technology, emission of gases can be controlled to some extent. The development of carbon fiber reinforced plastic is yet another way to decrease the weight of the car bodies and thus to reduce the fuel consumption.
