Introduction: Scope of the Book (Book Chapter)

Since the realization that the future of chemical/industrial processes primarily depends on their sustainable quotient, the path of modern science has shifted toward the improvement of processes/products following green chemistry princi�ples [1, 2]. Green chemistry as a branch of chemistry primarily deals with developing chemical processes using environmentally benign protocols, including inexpensive renewable less-toxic precursors. In that respect, the “12 rules of green chemistry,”
first formally introduced by Anastas and Warner in their book “Green Chemistry: Theory and Practices” [3], play a pivotal role in identifying the areas that should be focused to achieve the expected sustainability goals [4]. For chemical processes,
the main aim of introducing these 12 principles is to save the environment and society by reducing the usage of toxic and hazardous chemicals and solvents without affecting the product yield/selectivity. While the 12 principles are quite
self-explanatory, as depicted in Figure 1.1, the emphasis in certain areas often depends on the convenience of implementing them for specific protocols and the
outcome. Of these 12 principles, this book focuses on the historical and recent developments of strategies that minimize solvent use in a chemical process, often termed “solvent-free synthesis,” and the associated catalytic procedures involving
nanomaterials.