CHAPTER 4: Subcritical Water: Current Status, Advances, and Applications for Extractions, Reactions and Separations

Using renewable and sustainable solvents in a range of industrial processes is a topic at the forefront of innovation for a novel bioeconomy. To keep up with developments in society, investors from the private sector have been investing in promising technologies that use subcritical water for different purposes. Consequently, several scientific studies have focused on applications of subcritical water as a solvent and/or reagent, especially in the chemical, pharmaceutical and food-related areas. In this context, this book chapter presents a constructive overview of the reality and expectations of using subcritical water for extractions, reactions and separations. Phenolic acids, flavonoids, fructooligosaccharides and other functional compounds of high quality can be obtained by subcritical water extraction, which is a process that fits the green technology concept. Hydrolysis and other reactions under subcritical conditions are also reviewed. Therefore, recent advances and future outlooks on the extraction/production of different chemical compounds using subcritical water are provided in this chapter.