“Atom Economy” in Green Chemical Technology

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“Atom Economy” in Green Chemical Technology

Post  yufei on Thu Jun 30, 2011 1:53 pm

Green chemical technology refers to techniques which can be used to prevent environmental pollution from the source of development on the basis of green chemistry. It is known to all that most of chemical techniques at present were invented nearly 20 years ago which has some shortcomings. In addition, the processing cost at that time mainly included the fees of raw materials, energy consumption and labors. However, chemical industry has discharged too many venomous matters to the air, water and earth. Therefore, the processing cost should contain the fees to the control, and treatment of the wastes and to conduct environmental monitoring and so on. So it is necessary to improve the conventional chemical technology and to develop green chemical industry. Among these reformed technologies, “atom economy” reaction is the optimal one. “Atom economy” reaction is to converse each atom into products without any wastes or secondary products which can realize “zero transmission” of the wastes. At the same time, “atom economy” reaction refuses venomous raw materials, catalysts and solvents and produces environmental-friendly products.

“Atom economy” refers to the percentage of atoms in raw materials conversed into products. The ideal atom economy reaction is to converse each atom into products without any wastes or secondary products which can realize “zero transmission” of the wastes. Because of large yielding capacity of basic organic raw materials in a large amount, it is quite important to choose atom economy reaction. Some processes of basic organic raw materials production have adopted atom economy reaction, such as the polymerization of ethylene or propylene. In addition, some reactions of other basic organic raw materials productions have conversed from two-step reactions into one-step atom economy reaction. Take the production of ethylene oxide as an example. Nowadays, the production of ethylene oxide has adopted atom economy reaction oxidized directly by ethylene catalyzed by copper.

In recent years, it has been a hot issue to develop new atom economy reaction. For example, EniChem Company takes titanium silicalite catalyst and directly produces cyclohexanone oxime through the reactions of cyclohexanone, ammonia and peroxide, which can basically realize atom economy reaction. The company has made the process industrialized. Although the present atom economy reaction is rather good, it is too complex to separate the former catalyst used in the reactions with the final products. Therefore, there is a wide space to improve the catalysts. In recent years, people pay great attention to the study of water-soluble homogeneous catalyst which has been an important research field. It is relatively easy to separate water-soluble homogeneous catalyst with the products. In addition, with water as solvent, it can avoid to make use of volatile organic solvents. Therefore, the study of water-soluble homogeneous catalyst has already been a hot issue all over the world. A lot of research has already been put on the issue in our country. It can be said that more research from the aspects of environmental protection and technology should be conducted to improve atom economy reaction which has already been used in industries.

yufei

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