Benign chemical

Source reduction includes any in-plant actions to reduce the quantity or the toxicity of the waste at the source. Examples include equipment modification, design and operational changes of the process, reformulation or redesign of products, substitution of raw materials, and use of environmentally benign chemical reactions. 

An important element of pollution prevention is the selection of environmentally benign chemical reactions, raw materials, solvents, and products. Over the past few years, significant progress has been made in this area. This chapter provides a brief overview of the recent advances in synthesizing green reactions and species. For more detailed discussion, the reader is referred to Anastas and lliamson (1996), Anastas and Farris (1994), and Chase (1995). 

Anastas, P. and Williamson, T.C. (eds) (1998) Green Chemistry Frontiers in Benign Chemical Syntheses and Processes, Oxford University Press, Inc., New York, 364 p. 

Many academic texts are available to teach chemists the fundamental tools of their trade, but few books are designed to give future industrial research and development chemists the knowledge they need to contribute, with confidence and relevance, to the development of new environmentally benign chemical technology. This book aims to be a handbook for those chemists attempting to develop new processes and products for the twenty-first century, which meet the evermore stringent demands of a society that wants new products with improved performance, and with a lower financial and environmental price tag. 

Within the broad framework of sustainable development, we should strive to maximize resource efficiency through activities such as energy and nonrenewable resource conservation, risk minimization, pollution prevention, minimization of waste at all stages of a product life-cycle, and the development of products that are durable and can be re-used and recycled. Sustainable chemistry strives to accomplish these ends through the design, manufacture and use of efficient and effective, more environmentally benign chemical products and processes". 

S. Buelow, P. Dell Orco, D. K Morita, D. Pesiri, E Bim-baum, S. L Borkowsky, G. H. Brown, S. Feng, L Luan, D. A. Morgenstern, W. Tumas, Recent Advances in Chemistry and Chemical Processing in Dense Phase Carbon Dioxide at Los Alamos , In Green Chemistry Frontiers in Benign Chemical Syntheses and Processes, (Eds. P. T. Anastas and T. C. Williamson), Oxford University Press, Oxford, 1998, pp. 265-285. 

The first use of supercritical fluid extraction (SFE) as an extraction technique was reported by Zosel [379]. Since then there have been many reports on the use of SFE to extract PCBs, phenols, PAHs, and other organic compounds from particulate matter, soils and sediments [362, 363, 380-389]. The attraction of SFE as an extraction technique is directly related to the unique properties of the supercritical fluid [390]. Supercritical fluids, which have been used, have low viscosities, high diffusion coefficients, and low flammabilities, which are all clearly superior to the organic solvents normally used. Carbon dioxide (C02, [362,363]) is the most common supercritical fluid used for SFE, since it is inexpensive and has a low critical temperature (31.3 °C) and pressure (72.2 bar). Other less commonly used fluids include nitrous oxide (N20), ammonia, fluoro-form, methane, pentane, methanol, ethanol, sulfur hexafluoride (SF6), and dichlorofluoromethane [362, 363, 391]. Most of these fluids are clearly less attractive as solvents in terms of toxicity or as environmentally benign chemicals. Commercial SFE systems are available, but some workers have also made inexpensive modular systems [390]. 

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. ... 

Many progressive companies have used the Substitution Principle to move towards the goal of clean production. Some downstream users of chemicals claim to only use benign chemicals in their processes and products. For instance, the McDonough Braungart team of consultants has worked with the Design Tex company to produce a carpet that is made with non-hazardous chemicals from their Positive chemical list. ... 

In the search for environmentally benign chemicals that might deter birds such as starlings, crows, or pigeons from roosting en masse, spices and herbs such as rosemary, cumin, and thyme look promising. In some experiments, the birds feet were immersed in oil extracts of the spices. Starlings also avoided perches treated with starch mixes of (R)-limonene, (S)-limonene, (3-pinene, or methiocarb. The first three occur in rosemaiy, cumin, and thyme (Clark, 1997). 

The use of water instead of organic solvents is key to attaining the goal of environmentally benign chemical synthesis. In this context, organic reactions in water are now of great interest and much research effort has been devoted to pursuing efficient reactions in water [1-5]. Unique reactivity and selectivity have been often observed in aqueous media, but one of the big issues is the stability of catalysts in water. Many active catalysts are not stable in water but decompose in the presence of even a small amount of water. To overcome this, we searched for efficient catalysts that are stable and can work well in aqueous media. 

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."... 

Anastas, Paul, and Tracy C. Williamson. Green Chemistry Frontiers in Benign Chemical Synthesis and Processes. New York Oxford University... 

Uses environmentally benign chemical additives in the treatment process. 

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. 

P. T. Anastas, J. C, Warner, Green Chemistry, Oxford University Press, Oxford, 1998 Frontiers in Benign Chemical Syntheses and Processes, P. T. Anastas, T. C. Williamson, Eds. Oxford University Press, Oxford, 1998. 

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