Environmentally Benign Green Processing

The term green chemistry, describes an area of research and chemical practice that arises from scientific discoveries about pollution and ecological interdependence. Green chemistry is not necessarily environmental chemistry, although it may involve some of this. It is chemistry for the environment. The term, which was coined at the Environmental Protection Agency by Paul Anastas, advances the belief that environmentally benign chemical processes are possible and desirable. This supposition has been demonstrated to be trae in a number of significant cases. 

Green chemistry has been developed to meet the increasing demand for environmentally benign chemical processes. The use of room temperature ionic hquids (ILs) as either solvents or catalysts has attracted much attention in recent years [1]. ILs consist entirely of ions and have no measurable vapor pressure that makes them attractive as alternative solvents for homogeneous catalysis. Their polar nature allows the stabilization of ionic transition metal complexes and metal nanoparticles (NPs) [2],... 

Hydrothermal method is attracting worldwide attention because of the search for more green or environmentally benign chemical process [12]. Hydrothermal reaction involves applying heat under pressure to achieve reaction in an aqueous medium. Water above its critical point (374 °C, 22.1 MPa) is called supercritical water (SCW). 

SCFs are a class of promising green solvents in the development of environmentally benign chemical processes. Scientists and engineers have been very much interested in SCF science and technology in the last decades because of their unique properties and great potential of applications in different fields [4], such as extraction and separation [5], chemical reactions [6], and materials science [7]. Supercritical (sc) or compressed CO2, which is nontoxic, abundant, and nonflammable, can also be used to tune the physical properties of liquid solvents because its solubility in Hquids changes continuously with pressure and/or temperature [8]. 

We have reported a simple, green, bench top, economical and environmentally benign room temperature synthesis of MSe (M=Cd or Zn) nanoparticles using starch, PVA and PVP as passivating agents. The whole process is a redox reaction with selenium acting as the oxidant and MSe as the reduction product. An entire "green" chemistry was explored in this synthetic procedure and it is reproducible. The optical spectroscopy showed that all the particles are blue shifted from the bulk band gap clearly due to quantum confinement. Starch capped CdSe nanoparticles showed the presence of monodispersed spherical... 

Zero emission plants, environmentally benign or green chemistry, and sustainable development have become the catch phrases of the 1990s (Anastas and Farris, 1994 Anastas and Warner, 1998 Anastas and Williamson, 1998 Clark, 1995). Consequently, traditional concepts of process efficiency are changing from an exclusive focus on chemical yields to one that assigns economic value to eliminating waste and avoiding the use of toxic and/or... 

Nitrate Nonahydrate, IUPAC CHEM-RAWN XIV World Conf. Green Chemistry Toward Environmentally Benign Processes and Products, University of Colorado, Boulder, June 9-13, 2001. 

In recent years, the evaluation of environmentally benign (so-called "green" processes) has been a focal point of oxo developments, according to the definitions and targets of the... 

To overcome health and environmental problems at the source, the chemical industry must develop cleaner chemical processes by the design of innovative and environmentally benign chemical reactions. Green chemistry offers the tools for this approach. ... 

Within a year of the act s adoption, the EPA had assigned responsibility for its implementation to the Office of Pollution Prevention and Toxics, formed in 1977 to administer the Toxic Substances Control Act, and had begun the first federally funded green chemistry programs. By 1992, the National Science Foundation had also begun funding research on "environmentally benign [chemical] syntheses and processes."... 

Research in green chemistry is making dramatic achievements in the design of chemicals, chemical syntheses, and chemical processes that are environmentally benign and economically feasible. 

The implementation of the Montreal Protocol, the Clean Air Act, and the Pollution Prevention Act of 1990 has resulted in increased awareness of organic solvent use in chemical processing. The advances made in the search to find green replacements for traditional solvents have been tremendous. With reference to solvent alternatives for cleaning, coatings, and chemical reaction and separation processes, the development of solvent databases and computational methods that aid in the selection and/or design of feasible or optimal environmentally benign solvent alternatives for specific applications have been discussed (Sherman et al., 1998). 

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