Green chemistry, solid waste

A green chemistry variation makes use of solventless conditions to minimize the waste stream from reactions of this type. To a mortar are added aldehyde 67, ketone 68 and solid sodium hydroxide. The mixture is ground and within 5 minutes aldol product 69 is produced. Addition of the second ketone and further grinding affords the 1,5-diketone 70, which can be isolated and cyclized to pyridine 71 with ammonium acetate. The authors report that this method can substantially reduce the solid waste (by over 29 times) and is about 600% more cost effective than previously published procedures. 

Chemistry of the Environment focuses on the role of chemistry in environmental issues, including air and water pollution, solid wastes, and the relatively new field of green chemistry. The term pollution refers to the release of harmful or ohjectionahle substances into the environment, most commonly as the result of human activities. Some of the most obvious examples of pollution are smoke produced by industrial operations, carbon dioxide and other gases released into the atmosphere as a by-product of burning fuels, silt and sediment washed off land by rainwater, and garbage dumped on land. 

These materials are thus promising heterogeneous catalysts for the oxidation of p-isophorone to ketoisophorone. This novel method corresponds to several criteria of green chemistry and sustainable development (1) support from inexpensive renewables, (2) dioxygen as an oxidant, (3) combination of basic and oxidation sites in one solid material to avoid an addition of external base or other additives resulting in no wastes, and (4) easy separation of catalyst from reaction mixture and possibility of recycling. 

The need to implement green chemistry principles (e.g., safer solvents, less hazardous chemical synthesis, atom economy, and catalysis) is a driving force toward the avoidance of the use of toxic organic solvents. A solvent-free or solid-state reaction obviously reduces pollution and reduces handling costs due to simplification of experimental procedure and workup technique and savings on labor. However, interest in the environmental control of chemical processes has increased remarkably in the last three decades as a response to public concern about the use of hazardous chemicals. Therefore, to improve the effectiveness of this method in preventing chemical waste, it is important to investigate its optimal conditions. 

Malester, I., Green, M., Shelef, G., 1992. Kinetics of dilute acid hydrolysis of cellulose originating from municipal solid wastes. Industrial and Engineering Chemistry Research 31, 1998-2003. 

The use of zeolites in the manufacture of cumene is of immense importance. About 7 million metric tons of cumene are produced annually worldwide. The earlier-used process involved alkylation of benzene over a solid phosphoric acid or an aluminum chloride catalyst. Cumene Production, U.S. Patent 4008290. Both catalysts are toxic in nature. The Mobil/Badger cumene process (Mobil Technology Co., 1997) uses the less toxic carozine zeolite catalyst (see Fig. 3.7). In addition, it also generates less waste and requires less energy than the earlier catalysts, thus simultaneously satisfying various conditions of green chemistry. 

We have made a number of improvements in this edition that significantly improve safety in the laboratory. We have added several new experiments that incorporate the principles of Green Chemistry. The Green Chemistry experiments decrease the need for hazardous waste disposal, leading to reduced contamination of the environment. These experiments involve techniques such as solid phase extraction and the use of a microwave reactor. Other experiments have been modified to reduce their use of hazardous solvents. The "Green Chemistry" essay has been revised. In our view, it is most timely that students begin to think about how to conduct chemical experiments in a more environmentally benign manner. Many other experiments have been modified to improve their reliability and safety. 

The reaction is used in the manufacture of plastics and pharmaceuticals. 3-Chloroperbenzoic add is somewhat shock-sensitive, however, and prone to explode. Secondly, 3-Chlorobenzoic acid is a waste product An alternative process being developed uses hydrogen peroxide and a catalyst consisting of tin dqxjsited within a solid support The catalyst is readily recovered from the reaction mixture, (a) What would you expect to be the other product of oxidation of the ketone to lactone by hydrogen peroxide (b) What principles of green chemistry are addressed by use of the proposed process ... 

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